Smithsonian Institution

Scholarly Press

Smithsonian Institution

Scholarly Press

smithsonian contributions to botany • number 96

Smithsonian Institution

Scholarly Press

Smithsonian Institution

Scholarly Press

Marine Algae of the Northern 

Gulf of California II:

Rhodophyta

James N. Norris
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smithsonian contributions to botany • numb e r 9 6

Marine Algae of the Northern 

Gulf of California II: 

Rhodophyta

James N. Norris

WASHINGTON D.C.

2014
ABSTRACT

Norris, James N. Marine Algae of the Northern Gulf of California II: Rhodophyta. Smithsonian Contributions to Botany, number 96, xvi + 555 pages, 236 figures, 2014.— The present treatment constitutes a taxonomic study of the benthic 

marine red algae known in the northern Gulf of California. In all, 387 species of Rhodophyta belonging to two subphyla 

were found: the Rhodophytina, represented by 2 classes, 2 orders, 2 families, 7 genera, and 14 species; and Eurhodophytina, represented by 2 classes, 5 subclasses, 19 orders, 47 families, 133 genera, and 373 species (including varieties, forms, 

and possible new species); 71 species of red algae (~18%) are endemic to the Gulf of California. Together with the 133 

species of Chlorophyta and Phaeophyceae, 520 marine algae are known in the northern Gulf. The systematic account 

includes the presently accepted taxon name, descriptions of the subphyla, classes, orders, families, genera, and species, with 

keys and illustrations to aid in their identification. Along with the taxon name are its basionym, synonyms, author(s), date 

and place of valid publication, type locality, relevant taxonomic studies, description, habitat, and distribution in the Gulf 

of California and, if applicable, in the eastern, central, and/or western Pacific. A remarks section includes information on 

taxonomy, nomenclature, ecology, distribution extensions and new records, and/or other problems or facts of interest. A 

new genus, 1 new subgeneric section, and 8 new species are described; 30 new combinations are proposed (listed in Appendix 1). A new name, Rhodymenia huertae, is chosen to replace an illegitimate name; a lectotype illustration is selected for 

Laurencia paniculata Kützing; 15 previously reported species are considered uncertain records; and 3 species are excluded 

from the Gulf’s marine flora.

Cover images, left to right: Figures 170A (Pugetia mexicana), 231A (Botryocladia datilensis), 217 (Predaea japonica), and 

219A (Plocamium katinae) from this publication.

Published by SMITHSONIAN INSTITUTION SCHOLARLY PRESS

P.O. Box 37012, MRC 957

Washington, D.C. 20013-7012

www.scholarlypress.si.edu

This publication is in the public domain.

Library of Congress Cataloging-in-Publication Data

Norris, James N. 

Marine algae of the northern Gulf of California II: Rhodophyta / James N. Norris.

 p. cm. — (Smithsonian contributions to botany ; no. 96)

Includes bibliographical references and index.

1. Marine algae—Mexico—California, Gulf of. I. Title. II. Series: Smithsonian contributions to botany ; no. 96. 

QK571.9.C35N68 2014

579.8’9091641—dc23

2011023706

ISSN: (print) 0081-024X; (online) 1938-2812

Publication date: 14 November 2014

c The paper used in this publication meets the minimum requirements of the American National Standard for Permanence 

of Paper for Printed Library Materials Z39.48–1992. 
Contents

LIST OF FIGURES ix

INTRODUCTION 1

RED ALGAE 11

PHYLUM RHODOPHYTA 11

PART I. SUBPHYLUM RHODOPHYTINA 13

Part IA. STYLONEMATOPHYCEAE 13

 Stylonematales 13

 Stylonemataceae 13

 Chroodactylon Hansgirg 14

 Stylonema Reinsch 14

Part IB. COMPSOPOGONOPHYCEAE 16

 Erythropeltidales 17

 Erythrotrichiaceae 17

 Erythrocladia Rosenvinge 17

 Erythropeltis F. Schmitz 19

 Erythrotrichia Areschoug 19

 Porphyrostromium Trevisan 23

 Sahlingia Kornmann 24

PART II. SUBPHYLUM EURHODOPHYTINA 25

PART IIA. BANGIOPHYCEAE 26

 Bangiales 26

 Bangiaceae 26

 Bangia Lyngbye 27

 Pyropia J. Agardh 29

PART IIB. FLORIDEOPHYCEAE 34

 HILDENBRANDIOPHYCIDAE 35

 Hildenbrandiales 35

 Hildenbrandiaceae 35

 Hildenbrandia Nardo 35
i v • SMITHSONIAN CONTRIBUTIONS TO BOTANY

 NEMALIOPHYCIDAE 37

 Acrochaetiales 38

 Acrochaetiaceae 38

 Acrochaetium Nägeli 39

 Colaconematales 44

 Colaconemataceae 44

 Colaconema Batters 44

 Nemaliales 50

 Galaxauraceae 51

 Dichotomaria Lamarck 52

 Galaxaura J. V. Lamouroux 56

 Tricleocarpa Huisman et Borowitzka 60

 Liagoraceae 62

 Ganonema K.-C. Fan et Y.-C. Wang 63

 Izziella Doty 64

 Liagora J. V. Lamouroux 65

 Scinaiaceae 68

 Scinaia Bivona-Bernardi 68

 Palmariales 74

 Rhodophysemataceae 74

 Rhodonematella Clayden et G.W. Saunders 75

CORALLINOPHYCIDAE 76

 Corallinales1 76

 Corallinaceae 77

 Corallinaceae subfam. Corallinoideae 79

 Corallinoideae tribus Corallineae 79

 Corallina Linnaeus 80

 Corallinoideae tribus Janieae 84

 Haliptilon (Decaisne) Lindley 84

 Jania J. V. Lamouroux 85

 Corallinaceae subfam. Amphiroideae 92

 Amphiroa J. V. Lamouroux 93

 Corallinaceae subfam. Lithophylloideae 101

 Litholepis Foslie 102

 Lithophyllum Philippi 102

 Pseudolithophyllum Me. Lemoine 111

 Titanoderma Nägeli 112

 Corallinaceae subfam. Hydrolithoideae 115

 Hydrolithon (Foslie) Foslie 115

 Corallinaceae subfam. Mastophoroideae 118

 Heteroderma Foslie 119

 Fosliella M. Howe 121

 Pneophyllum Kützing 122

 Spongites Kützing 124

 Corallinaceae subfam, Neogoniolithoideae 127

 Neogoniolithon Setchell et L. R. Mason 127

 Corallinaceae subfam. Porolithoideae 129

 Porolithon Foslie 129

 Hapalidiaceae 131

 Hapalidiaceae subfam. Choreonematoideae 132

 Choreonema F. Schmitz 132

1 Contributed by James N. Norris and H. William Johansen.
NUMBER 96 • v

 Hapalidiaceae subfam. Melobesioideae 133

 Lithothamnion Heydrich 133

 Melobesia J. V. Lamouroux 136

 Mesophyllum Me. Lemoine 139

AHNFELTIOPHYCIDAE 141

 Ahnfeltiales 141

 Ahnfeltiaceae 141

 Ahnfeltia Fries 141

RHODYMENIOPHYCIDAE 142

 Bonnemaisoniales 143

 Bonnemaisoniaceae 143

 Asparagopsis Montagne 144

 Bonnemaisonia C. Agardh 146

 Ceramiales2 149

 Callithamniaceae 149

 Callithamniaceae tribus Callithamnieae 150

 Aglaothamnion Feldmann-Mazoyer 150

 Callithamnion Lyngbye 151

 Callithamniaceae tribus Crouanieae 153

 Crouania J. Agardh 153

 Crouanophycus Athanasiadis 155

 Ceramiaceae 157

 Ceramiaceae tribus Antithamnieae 158

 Antithamnion Nägeli 158

 Ceramiaceae tribus Dohrnielleae 161

 Antithamnionella Lyle 161

 Irtugovia Perestenko 166

 Ceramiaceae tribus Delesseriopseae 167

 Balliella Itono et Tak. Tanaka 167

 Ceramiaceae tribus Ceramieae 168

 Centroceras Kützing 168

 Ceramium Roth 171

 Corallophila Weber-van Bosse 193

 Gayliella T. O. Cho, L. McIvor et S. M. Boo 195

 Ceramiaceae tribus Pterothamnieae 199

 Pterothamnion Nägeli in Nägeli et Cramer 199

 Dasyaceae 203

 Dasyaceae subfam. Dasyoideae 204

 Dasya C. Agardh 204

 Dasyaceae subfam. Heterosiphonioideae 210

 Heterosiphonia Montagne 210

 Delesseriaceae 212

 Apoglossum J. Agardh 214

 Branchioglossum Kylin 216

 Caloglossa (Harvey) G. Martens3 218

 Erythroglossum J. Agardh 221

 Grinnellia Harvey 222

 Hypoglossum Kützing 223

 Myriogramme Kylin 224

 Phycodrys Kützing 227

2 Contributed by Katina E. Bucher and James N. Norris.

3 Contributed by James N. Norris and David M. Krayesky.
v i • SMITHSONIAN CONTRIBUTIONS TO BOTANY

 Polyneurella E. Y. Dawson 228

 Schizoseris Kylin 230

 Sorella Hollenberg 233

 Taenioma J. Agardh 235

 Sarcomeniaceae 236

 Platysiphonia Børgesen 236

 Rhodomelaceae 238

 Rhodomelaceae tribus Bostrychieae 239

 Bostrychia Montagne 239

 Rhodomelaceae tribus Chondrieae 240

 Chondria C. Agardh 240

 Digenea C. Agardh 243

 Rhodomelaceae tribus Herposiphonieae 244

 Herposiphonia Nägeli 244

 Rhodomelaceae tribus Laurencieae 248

 Laurencia J. V. Lamouroux 249

 Chondrophycus (J. Tokida et Y. Saito) 

Garbary et J. Harper 255

 Osmundea Stackhouse 255

 Palisada K. W. Nam 258

 Rhodomelaceae tribus Polysiphonieae 261

 Neosiphonia M.-S. Kim et I. K. Lee 261

 Neosiphonia M.-S. Kim et I. K. Lee sect. 

Neosiphonia 263

 Neosiphonia sect. Multisiphonia J. N. Norris, 

sect. nov. 270

 Polysiphonia Greville 274

 Polysiphonia sect. Oligosiphonia J. Agardh 275

 Rhodomelaceae tribus Pterosiphonieae 279

 Pterosiphonia Falkenberg in F. Schmitz 

and Falkenberg 279

 Pterosiphoniella E. Y. Dawson 281

 Tayloriella Kylin 282

 Placophora group 284

 Amplisiphonia Hollenberg 284

 Rhodomelaceae tribus Brongniartelleae 286

 Veleroa E. Y. Dawson 286

 Spyridiaceae 288

 Spyridia Harvey 288

 Wrangeliaceae 291

 Wrangeliaceae tribus Griffithsieae 291

 Anotrichium Nägeli 291

 Griffithsia C. Agardh 295

 Wrangeliaceae tribus Spermothamnieae 296

 Lejolisia Bornet 296

 Tiffaniella Doty et Meñez 297

 Wrangeliaceae tribus Spongoclonieae 300

 Pleonosporium Nägeli 300

 Gelidiales4 304

 Gelidiaceae 305

 Gelidium J. V. Lamouroux 305

4 Contributed by James N. Norris and Joan G. Stewart.
NUMBER 96 • vii

 Gelidiellaceae 312

 Gelidiella J. Feldmann et G. Hamel 313

 Pterocladiaceae 314

 Pterocladia J. Agardh 315

 Pterocladiella Santelices et Hommersand 316

 Gigartinales 318

 Caulacanthaceae 319

 Caulacanthus Kützing 319

 Cystocloniaceae 320

 Hypnea J. V. Lamouroux 321

 Dicranemataceae 325

 Dicranema Sonder 325

 Dumontiaceae 327

 Dudresnaya P. Crouan et H. Crouan 327

 Gigartinaceae5 328

 Chondracanthus Kützing 329

 Mazzaella G. De Toni 334

 Kallymeniaceae 338

 Kallymenia J. Agardh 338

 Pugetia Kylin 342

 Crossocarpaceae 344

 Kallymeniopsis Perestenko 344

 Phyllophoraceae6 345

 Ahnfeltiopsis P. C. Silva et DeCew 346

 Gymnogongrus Martius 349

 Petroglossum Hollenberg 350

 Solieriaceae 352

 Agardhiella F. Schmitz 353

 Sarcodiotheca Kylin 353

 Tacanoosca J. N. Norris, P. W. Gabrielson 

et D. P. Cheney, gen. nov. 360

 Wurdemannia Harvey 363

 Weeksiaceae 363

 Weeksia Setchell 364

 Peyssonneliales7 366

 Peyssonneliaceae 366

 Cruoriella P. Crouan et H. Crouan 367

 Metapeyssonnelia Boudouresque, 

Coppejans et Marcot 369

 Peyssonnelia Decaisne 370

 Gracilariales8 374

 Gracilariaceae 374

 Gracilaria Greville 375

 Gracilariopsis E. Y. Dawson 397

 Gracilariophila Setchell et H. L. Wilson 403

 Pterocladiophilaceae 404

 Gelidiocolax N. L. Gardner 404

5 Contributed by James N. Norris and Suzanne Fredericq.

6 Contributed by James N. Norris and Suzanne Fredericq.

7 Contributed by David M. Krayesky and James N. Norris.

8 Contributed by James N. Norris and C. Frederico D. Gurgel.
viii • SMITHSONIAN CONTRIBUTIONS TO BOTANY

 Cryptonemiales 405

 Halymeniaceae 405

 Cryptonemia J. Agardh 406

 Grateloupia C. Agardh 410

 Halymenia C. Agardh 417

 Prionitis J. Agardh 421

 Tsengiaceae9 426

 Tsengia K.-C. Fan et Y.-P. Fan 426

 Nemastomatales10 429

 Nemastomataceae 430

 Predaea G. De Toni 430

 Schizymeniaceae 432

 Platoma Schousboe ex F. Schmitz 433

 Schizymenia J. Agardh 434

 Plocamiales 436

 Plocamiaceae 436

 Plocamium J. V. Lamouroux 436

 Sebdeniales 439

 Sebdeniaceae 440

 Sebdenia (J. Agardh) Berthold 440

 Rhodymeniales 442

 Champiaceae 442

 Champia Desvaux 443

 Gastroclonium Kützing 445

 Faucheaceae 449

 Gloiocladia J. Agardh 449

 Gloioderma J. Agardh 452

 Lomentariaceae 453

 Ceratodictyon Zanardini 455

 Lomentaria Lyngbye 457

 Rhodymeniaceae 460

 Botryocladia (J. Agardh) Kylin 461

 Irvinea Guiry in G. W. Saunders, I. M. Strachan 

et Kraft 464

 Rhodymenia Greville 465

ACKNOWLEDGMENTS 471

APPENDIX 1: New Names, Taxa, Combinations, and Typification 475

APPENDIX 2: Endemic Rhodophyta of the Gulf of California 

that Occur in the Northern Gulf 477

APPENDIX 3: Rhodophyta Specimens Illustrated: Species Locality 

Information and Herbarium 479

REFERENCES 497

INDEX OF SCIENTIFIC NAMES 543

9 Contributed by Katina E. Bucher and James N. Norris.

10 Contributed by Katina E. Bucher and James N. Norris.
Figures

1. Map of Gulf of California and surrounding region 2

2. Map of the northern Gulf of California, Mexico 3

3. Some northern Gulf of California collecting sites 4

4. Sonoran desert shore of the northern Gulf 5

5. Research vehicle; collections gear; marine botanists James Norris, 

Katina Bucher; Norris with Armando Torres, Angelita Torres 6

6. Playa Las Conchas (Playa Estación), Puerto Peñasco, at low tide; 

K. Bucher surveying Cumpleaños Tide Pool 7

7. Comparisons of intertidal macroalgae coverage 8

8. Some northern Gulf red algae: Jania capillacea on Sargassum; 

Corallina and crustose corallines among Chondracanthus, 

Colpomenia tuberculata, and C. phaeodactyla; Tacanoosca uncinata; 

Chondracanthus squarrulosus; Palisada paniculata; Porolithon 

sonorense 9

9. Stylonema alsidii and S. cornu-cervi 16

10. Erythrocladia irregularis and Sahlingia subintegra 18

11. Erythrotrichia biseriata, developing filament with basal cell 20

12. Erythrotrichia biseriata and E. carnea f. tenuis 21

13. Erythrotrichia parksii var. minor, unbranched filament 22

14. Erythrotrichia tetraseriata filaments 23

15. Porphyrostromium boryanum and P. ciliare 24

16. Bangia enteromorphoides 28

17. Bangia vermicularis? 29

18. Habits of Porphyra thuretii and P. pendula; detail of reproductive 

margin of P. thuretii 32

19. Conchocelis-phase of Pyropia, habit of growing filaments 33

20. Hildenbrandia prototypus, section of crust with a tetrasporangial 

conceptacle 36

21. Acrochaetium arcuatum, A. porphyrae, A. secundatum, and 

A. seriaspora 40

22. Acrochaetium crassipes, habits of two epiphytes 41

23. Colaconema hancockii (type), C. pacificum, C. punctatum, C. variabile,

C. sinicola (type), C. tenuissimum, and C. scinaiae 46

24. Dichotomaria marginata, habit of gametophyte; transections with 

spermatangial cavities 54
x • SMITHSONIAN CONTRIBUTIONS TO BOTANY

25. Dichotomaria spathulata, habit of tetrasporophyte; transections 

of cortex 55

26. Galaxaura ramulosa, habit of sporophytes and cortical anatomy 58

27. Galaxaura rugosa, habit of a gametophyte and cortical anatomy 59

28. Tricleocarpa cylindrica, habit of gametophyte and cortical anatomy 61

29. Ganonema farinosum, different habits 64

30. Liagora ceranoides, gametophyte habit 66

31. Liagora magniinvolucra, gametophyte habit; medullary and cortical 

filaments 67

32. Scinaia confusa, female gametophyte; transection and surface views 

of cortex 70

33. Scinaia johnstoniae, habit of male gametophytes and morphological 

variations 71

34. Scinaia johnstoniae, surface view and transection of cortex 72

35. Scinaia latifrons, habit of female gametophyte with marginal 

cystocarps 73

36. Corallina officinalis var. chilensis and C. vancouveriensis 81

37. Corallina pinnatifolia var. pinnatifolia; C. polysticha; C. pinnatifolia 

var. digitata 82

38. Jania adhaerens, epiphytic habit and decalcified branches 87

39. Branching patterns, variation of Jania adhaerens, J. crassa, 

J. longiarthra, J. capillacea, J. mexicana 88

40. Jania huertae (type specimen), habit and branching pattern 90

41. Amphiroa beauvoisii, branching variability 95

42. Amphiroa misakiensis, irregular branching patterns and branches 

with conceptacles 97

43. Amphiroa valonioides, habit, longitudinal section, and branches 

with conceptacles 99

44. Amphiroa vanbosseae, habit, branch variation, and branches with 

conceptacles 101

45. Litholepis sonorensis and Heteroderma corallinicola, transections 103

46. Lithophyllum diguetii, rhodolith habit variability 105

47. Lithophyllum hancockii, habit (holotype) 106

48. Lithophyllum imitans, conceptacles, crust surface; L. margaritae, 

habit variation 107

49. Lithophyllum pallescens, habit variability, protuberances 109

50. Lithophyllum proboscideum, protuberances 110

51. Titanoderma dispar, epiphytic crusts surrounding host branches 114

52. Hydrolithon farinosum, surface views of decalcified crust 117

53. Heteroderma gibbsii, habit of crust epiphytic on Padina 120

54. Heteroderma gibbsii, transections of crust and algal hosts 121

55. Heteroderma subtilissimum, drawings of transection and crust 

surface view 121

56. Spongites decipiens, habit and crust, transection and surface detail 

of crust 126

57. Neogoniolithon trichotomum, habits, branch tips, longitudinal 

section of branch 128

58. Porolithon sonorense, habits of type collection, crust and plate detail 131

59. Lithothamnion australe, rhodoliths showing subcylindrical branch 

variability 135

60. Lithothamnion microsporum, surface view of crusts 135

61. Mesophyllum crassiusculum, habits and close-up of crust surface 140

62. Ahnfeltia svensonii, habit 142

63. Asparagopsis taxiformis, habit of gametophyte and close-up 

of branches 145
NUMBER 96 • x i

64. Falkenbergia-phase of Asparagopsis 146

65. Bonnemaisonia hamifera, gametophyte habit, hook-shaped 

branchlets, branch tip 148

66. Callithamnion bisporum var. australe isotype, upper portion 

with bisporangia 152

67. Crouania attenuata, branched axis and whorl branches 154

68. Crouanophycus mcnabbii, branched axes, whorl branches, 

and tetrasporangia 156

69. Antithamnion decipiens, axis with whorl branches, gland cells, 

and tetrasporangia 159

70. Antithamnion defectum, axes and gland cells 160

71. Antithamnion kylinii, branching habit, tetrasporangia, and 

spermatangial structures 162

72. Antithamnionella breviramosa, habit, whorl branch variability, 

and tetrasporangia 164

73. Antithamnionella cf. spirographidis, decussately arranged 

whorl-branches and close-up 165

74. Centroceras gasparrinii, branching axes, spermatangia, and 

involucred tetrasporangia 170

75. Ceramium aduncum, branching habit and emergent tetrasporangia 173

76. Ceramium affine var. peninsularis, developing and mature 

cortical nodes 175

77. Ceramium caudatum, nodes and emergent tetrasporangia 176

78. Nodes of Ceramium aduncum, C. clarionense, and C. caudatum 177

79. Ceramium equisetoides and C. hamatispinum, tetrasporangia, 

axes, and nodes 180

80. Ceramium horridulum, habit and branch detail 181

81. Ceramium howellii, corticated axes, branches, and immersed 

tetrasporangia 182

82. Ceramium interruptum, tetrasporangial axis with cortication 

interrupted above dichotomy 183

83. Ceramium mazatlanense, involucred tetrasporangia and nodal 

cortication 185

84. Ceramium obesum, habit (type) and C. serpens (type) erect axes 

with tetrasporangia 186

85. Ceramium paniculatum, multicelluar spines, cortication pattern, 

involucred tetrasporangia 187

86. Ceramium periconicum, cortication pattern and tetrasporangia 189

87. Ceramium procumbens, branching pattern and tetrasporangia 190

88. Ceramium sinicola, axes with nearly complete cortication 191

89. Comparison of cortical units in Centroceras and Corallophila; detail 

of Corallophila bella 194

90. Gayliella fimbriata, nodal cortication of axes with protruding 

gland cells 196

91. Gayliella species A, nodal cortication patterns, tetrasporangia, 

and attachment rhizoid 197

92. Gayliella recticortica (paratype), nodal cortication pattern 198

93. Gayliella taylorii (paratypes), nodal cortication pattern 200

94. Pterothamnion orbignianum, axis with different pairs of whorl 

branches on axial cells 201

95. Pterothamnion pectinatum, branches, pairs of whorl branches 

on axial cells, tetrasporangia 202

96. Dasya pedicellata subsp. stanfordiana, habits, close-ups of 

corticated axis, spermatangial and tetrasporangial stichidia 205

97. Dasya pedicellata subsp. stanfordiana var. nudicaulis, habit 207
xii • SMITHSONIAN CONTRIBUTIONS TO BOTANY

98. Pseudolaterals of Dasya sinicola var. californica, D. spinigera, 

and D. sinicola var. sinicola 208

99. Dasya sinicola var. californica and D. sinicola var. sinicola 209

100. Heterosiphonia crispella var. laxa, axes with pseudolaterals, 

tetrasporangial and spermatangial stichidia 211

101. Heterosiphonia erecta, habit, close-up of polysiphonous axes 

with pseudolaterals 213

102. Apoglossum gregarium (type of Hypoglossum gregarium), habit, 

apical region, tetrasporangial sori 215

103. Branchioglossum bipinnatifidum, habit, blade apex, tetrasporangial 

and spermatangial sori 217

104. Branchioglossum undulatum, habit, secondary blades along margin 219

105. Caloglossa apomeiotica, constriction at branch node and peg-like 

attachment structure 220

106. Erythroglossum californicum, habit 222

107. Grinnellia lanceolata habits, blade apex, tetrasporangial sori 223

108. Hypoglossum attenuatum var. abyssicolum, habit, blade apex, 

cystocarp, spermatangial sori 225

109. Myriogramme divaricata, M. auricularis (type), and M. sp., habits, 

tetrasporangial sori, detail of blade margin 226

110. Phycodrys amplissima, habit and detail of denticulate margin 

of isotype 229

111. Phycodrys simplex, habit 229

112. Polyneurella hancockii, tetrasporic and cystocarpic blades, blade 

apex and slender veins 231

113. Schizoseris pygmaea, habits, blade surface with midrib 232

114. Sorella pinnata, habit, tetrasporangial sori, and close-up of blade 

surface and apices 234

115. Taenioma perpusillum, habit, close-ups of blades with hairs at apices 236

116. Platysiphonia decumbens, surface view of blades, branching, 

and apices 237

117. Chondria acrorhizophora, habits, including an isotype 241

118. Chondria species A, branching habit, and C. acrorhizophora, detail 

of branch tip 242

119. Digenea simplex, habit variations 244

120. Herposiphonia littoralis, habit, branching pattern 245

121. Herposiphonia plumula var. plumula, branching pattern 247

122. Herposiphonia plumula var. parva, branching pattern 247

123. Herposiphonia spinosa, habit and close-up of spine at branch tip 248

124. Laurencia aguilar-rosasorum (holotype), L. fenicalii (holotype), 

L. iriei (holotype), L. johnstonii, habits 251

125. Habits of Osmundea estebaniana and O. sinicola 257

126. Habits of Palisada paniculata and P. pedrochei (holotype) 260

127. Neosiphonia cheloniae, apical region and spermatangial stichidia 263

128. Apical portions of Neosiphonia concinna, N. confusa, N. johnstonii 

var. johnstonii, N. eastwoodae, and N. masonii 265

129. Neosiphonia flaccidissima, apical region, trichoblasts, lateral 

branches, scar cells 266

130. Neosiphonia savatieri, tetrasporangia in spiral series and cystocarps 267

131. Apical portion and cystocarps of Neosiphonia confusa and N. simplex 269

132. Apical regions of Neosiphonia mexicana, N. paniculata, and

Polysiphonia sonorensis 272

133. Neosiphonia paniculata, habit 273

134. Polysiphonia hollenbergii (holotype), axes with spermatangial stichidia 275
NUMBER 96 • xiii

135. Polysiphonia pacifica var. delicatula, branch apices lacking trichoblasts, 

pericentral cells with rhizoids 276

136. Polysiphonia scopulorum var. villum, trichoblasts rare, rhizoids with 

pericentral cells 278

137. Pterosiphonia dendroidea and P. californica, branching patterns 281

138. Pterosiphoniella williamsii, branching habit, spermatangial stichidia, 

and tetrasporangia 283

139. Amplisiphonia? pacifica, habit, apical area, and surface view of blade 285

140. Veleroa subulata (holotype), branching habit and tetrasporangia 287

141. Spyridia cf. filamentosa, habits, differing cortical patterns, and 

terminal spine 289

142. Anotrichium furcellatum, branching habit and pedicellate 

tetrasporangia 293

143. Anotrichium secundum, branching habit and apical area 294

144. Griffithsia pacifica, habit and apical area 295

145. Lejolisia hoshawii (holotype), branching habit and tetrasporangia 297

146. Tiffaniella saccorhiza and T. snyderae, habits with rhizoids and 

polysporangia 299

147. Pleonosporium globuliferum, branching habit, adaxial polysporangia, 

spermatangial heads 301

148. Pleonosporium mexicanum, branching pattern and adaxial 

polysporangia 302

149. Pleonosporium vancouverianum, branching habit and polysporangia 303

150. Habits of Gelidium mcnabbianum, G. microphysa (holotype),

G. refugiensis (holotype), and G. crinale 307

151. Gelidium decompositum, habit 308

152. Gelidium johnstonii, habits of female gametophyte and 

a tetrasporophyte 309

153. Habits of Gelidium mcnabbianum and G. pusillum 310

154. Gelidium pusillum, habit variability from various locations 311

155. Habits of Gelidiella hancockii and Pterocladiella caloglossoides (type) 314

156. Pterocladia sonorense, habit 316

157. Pterocladiella capillacea, habits 318

158. Hypnea cervicornis, habit 322

159. Dicranema rosaliae, habit, transections, and superficial spermatangia 326

160. Dudresnaya colombiana, habit, spermatangia, and carposporophyte 328

161. Chondracanthus acicularis, habit 330

162. Chondracanthus squarrulosus, habit variations 332

163. Chondracanthus tepidus, habit and branch 333

164. Chondracanthus zertuchei (holotype), habit 334

165. Mazzaella diffusa, habit and transection 335

166. Mazzaella digitata, habits (paratypes) and transection 336

167. Mazzaella hancockii, habit 337

168. Habits of Kallymenia baldwinii (holotype) and K. bleckii (holotype) 340

169. Kallymenia pertusa, habit of characteristic perforated blade 341

170. Pugetia mexicana, habits, including cystocarpic thallus 343

171. Ahnfeltiopsis hancockii, habits, tetrasporangial nemathecia 347

172. Ahnfeltiopsis serenei, habit 348

173. Gymnogongrus johnstonii, habits, variation of spinulose branchlet 

density 351

174. Petroglossum parvum, habits and transections 352

175. Sarcodiotheca dichotoma, habit variations, marginal cystocarps 355

176. Sarcodiotheca furcata, habit 356

177. Sarcodiotheca furcata, habit variations and cystocarp transection 357
xiv • SMITHSONIAN CONTRIBUTIONS TO BOTANY

178. Sarcodiotheca gaudichaudii, habits and male and female gametophytes 359

179. Sarcodiotheca taylorii, habits of a female gametophyte and 

a tetrasporophyte 360

180. Tacanoosca gen. nov., habit variations of T. uncinata, male and 

female gametophytes 362

181. Habit of Weeksia coccinea, transections of W. coccinea and 

W. templetonii 365

182. Weeksia templetonii, habit of a female gametophyte 365

183. Cruoriella fissurata, habit of the crust on rock 368

184. Cruoriella mexicana, vertical sections of sporophytic and 

nonreproductive crusts 368

185. Metapeyssonnelia mexicana, vertical sections of crusts 370

186. Peyssonnelia mexicana, habit, vertical sections of spermatangial 

crust, tetrasporangial nemathecia 372

187. Peyssonnelia orientalis, vertical sections through nonreproductive 

crusts, tetrasporic crust 373

188. Gracilaria ascidiicola (isotype), habits of its association with an 

ascidian and individual thalli 377

189. Gracilaria crispata, habits of cystocarpic and tetrasporic thalli 378

190. Transections of Gracilaria crispata, G. rubrimembra, and G. veleroae 379

191. Gracilaria pachydermatica, habits, holotype, and transections 381

192. Gracilaria pinnata, habit 384

193. Gracilaria ramisecunda (type collection), habits and transections 385

194. Gracilaria rubrimembra, habit variability 387

195. Gracilaria spinigera, habit 388

196. Gracilaria spinigera, habit, branch detail, longitudinal section, 

and transections 389

197. Habits of Gracilaria subsecundata and G. veleroae 390

198. Habits of Gracilaria tepocensis and G. turgida 391

199. Gracilaria vivesii, habit variations 395

200. Gracilariopsis animasensis, sp. nov., habits of holotype and female 

gametophyte, transection, longitudinal section 399

201. Gracilariopsis animasensis specimens from South Australia, 

transection of thallus 400

202. Gracilariopsis animasensis from South Australia, transections 401

203. Cryptonemia angustata, habit of tetrasporophyte 407

204. Habits of Cryptonemia guaymasensis and C. opuntioides (holotype) 408

205. Cryptonemia obovata, habits of blades, diagrammatic transection 409

206. Grateloupia catenata, habit and transection 412

207. Grateloupia hancockii, habits 413

208. Grateloupia howei, habit variation of large and small thalli 414

209. Grateloupia prolongata, habit variations 416

210. Grateloupia versicolor, habit 417

211. Grateloupia violacea, habit and transections of tetrasporic 

and cystocarpic thalli 418

212. Halymenia actinophysa, habit and squash preparations of female 

gametophyte 420

213. Halymenia megaspora, habit (paratype) 422

214. Habits of Prionitis abbreviata var. abbreviata, P. acroidalea, 

and P. abbreviata var. guaymasensis 424

215. Tsengia abbottiana, habit (holotype), carpogonial branch, 

connecting filaments 427

216. Tsengia abbottiana (holotype), detail of branching, cortical filament; 

Predaea masonii, habit 428
NUMBER 96 • x v

217. Predaea japonica, habit, cortical filaments, auxiliary cell with 

nutritive cellules 431

218. Schizymenia pacifica, female gametophyte habit, surface view 

and transection of gland cells in cortex 435

219. Plocamium katinae, sp. nov., habit (holotype), branches, 

tetrasporangial branchlets 438

220. Sebdenia flabellata, habit and transections 441

221. Habits of Champia disticha (holotype), C. caespitosa (holotype), 

and Gastroclonium compressum 444

222. Champia cf. parvula, habit, branch origin, tetrasporangia, 

longitudinal filaments 446

223. Gastroclonium pacificum, habit 448

224. Gloiocladia hoshawii, habits of holotype (with marginal coronate 

cystocarps) and tetrasporic thallus, branch transections 451

225. Gloiocladia mollis, habit 452

226. Gloiocladia sefferi, habits of narrow and wide cystocarpic thalli, 

transection of cystocarps 452

227. Gloioderma conjuncta, habit variation 454

228. Ceratodicyton variabile, wiry habit 456

229. Lomentaria catenata, habits of tetrasporophyte and female 

gametophyte 458

230. Lomentaria hakodatensis, habit 459

231. Botryocladia datilensis, habit, surface views of a vesicle, and groups 

of secretory cells 462

232. Botryocladia guaymasensis, habit variations and surface view 

of vesicle wall 463

233. Botryocladia uvarioides, habit and detail of secretory cells 464

234. Irvinea hancockii, habit of cystocarpic thallus 466

235. Habits of Rhodymenia dawsonii and R. divaricata (holotype) 467

236. Rhodymenia hancockii, habit variation 468

INTRODUCTION

The oceanography of the Gulf of California (Figure 1) has been described by Roden 

(1964), van Andel and Shor (1964), Álvarez-Borrego (1983, 2002), and Lavín and Marinone (2003), with overviews by Brusca (1980), Maluf (1983), Brusca et al. (2005), 

and Norris (2010). An atlas of the scientific cruises in the Gulf of California was given 

by Schwartzlose and Lluch-Cota (2003). The general features of the marine flora of the 

northern Gulf of California and its history of marine botanical exploration can be found 

in Norris (2010).

The systematic account of the Rhodophyta herein constitutes the companion volume 

of Marine Algae of the Northern Gulf of California; the first was the treatment of Chlorophyta and Phaeophyceae (Norris, 2010).

. . . 

The intertidal and subtidal algal collections that form the basis for the present taxonomic study of the red algae were made during land- and ship-based field trips to the Baja 

California and Sonora coasts of the northern Gulf of California and Islas de la Cintura 

(Figures 2–8). These field trips and ship expeditions occurred while I was in residence as 

Station Director of Laboratorio de Biología Marina of the University of Arizona and Universidad de Sonora in Puerto Peñasco, Sonora (Norris, 2010) (Figure 6), and since 1975 

after I came to work at the National Museum of Natural History. These were supplemented by the collections of E. Yale Dawson (Algal Collection, U.S. National Herbarium 

[US Alg. Coll.]; Allan Hancock Foundation Herbarium [AHFH], now Herbarium of the 

University of California, Berkeley [UC]) and those of Ivan M. Johnston and others that 

were included in the studies of W. A. Setchell and N. L. Gardner (Herbarium, California 

Academy of Sciences [CAS], now UC; US Alg. Coll.). The Gulf of California research was 

supported and encouraged by Robert W. Hoshaw, Donald A. Thomson, and John R. Hendrickson (University of Arizona), Michael Neushul (University of California, Santa Barbara), and Isabella A. Abbott (Stanford University and, later, University of Hawaii). Field 

explorations on the Sonora and Baja California coasts were made possible through support from National Science Foundation grants (BMS-73-07000-A01 and BMS-75-13960), 

USDC NOAA-04-5-158-20, and an American Philospohical Society grant (Penrose Fund 

no. 7530). The Islas de la Cintura (Midriff Islands) were surveyed during the cruise of the 

R/V Dolphin (Scripps Institution of Oceanography [SIO], University of California, San 

Marine Algae of the Northern Gulf of 

California II: Rhodophyta

James N. Norris

James N. Norris, Department of Botany, National 

Museum of Natural History, Smithsonian Institution, Washington, D.C., USA; norrisj@si.edu.

Manuscript received 13 July 2010; accepted 

19 May 2011.
2 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Diego [UCSD]) to the northern Gulf of California (Norris and 

Bucher, 1976, 1977) (Figure 3A–D).

 Specimens were obtained from the intertidal and subtidal 

by me and Katina E. Bucher using scuba (Norris, 2010). Collection numbers are designated by the following prefixes: 

JN our field notebooks (Algal Collection, National 

Museum of Natural History, Smithsonian Institution); 

EYD notebooks of E. Yale Dawson (Algal Collection, National Museum of Natural History, 

Smithsonian Institution);

GJH notebooks of George J. Hollenberg (Algal Collection, National Museum of Natural History, 

Smithsonian Institution); 

JN and HWJ H. William Johansen (Clark University; notebook with HWJ);

JS notebooks of Joan G. Stewart (Scripps Institution of Oceanography, UCSD).

Methods for field collection of marine algal specimens and 

their subsequent preservation, mounting as herbarium specimens, and preparation for light microscope study are as given by 

Tsuda and Abbott (1985). Photomicrographs were made using 

an Olympus Q-5 digital camera mounted on a Zeiss Universal 

microscope; all images used herein were prepared using Adobe 

Photoshop PS-4 on a Macintosh Pro computer. 

Specimens studied or examined, or referred to in this work 

are deposited in collections at the institutions listed below, which 

are abbreviated for subsequent mention in the text. Herbarium 

abbreviations herein follow the Index Herbariorum (Holmgren 

et al., 1990; Thiers, 2013).

AD State Herbarium of South Australia, Adelaide, 

South Australia, Australia

AHFH Herbarium of the Allan Hancock Foundation, 

University of Southern California, Los Angeles, 

California; Algae Collection moved to LAM, 

now UC

CAS Herbarium of the California Academy of Sciences, San Francisco, California; now UC

CMMEX Algae Herbarium of the Universidad Autónoma 

de Baja California, Facultad de Ciencias Marinas, Ensenada, Baja California, Mexico

CN Herbier, Université de Caen, Laboratoire de Biologie, Caen, France 

ENCB Herbario, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico D.F., Mexico

L Nationaal Herbarium Nederland, Leiden University, Leiden, Netherlands

LAM Algal Herbarium of the Los Angeles County 

Museum, Los Angeles, California; now UC 

LD Botanical Museum, Lund, Sweden

MICH Herbarium of the University of Michigan, Ann 

Arbor, Michigan 

MLML Marine Algae Collection, Marine Biological 

Collection (Museum), Moss Landing Marine 

Laboratories, California State University, Moss 

Landing, California

PC Muséum National d’Histoire Naturelle, Laboratoire de Cryptogamie, Paris, France

TCD Herbarium, School of Botany, Trinity College, 

Dublin, Ireland 

UC Herbarium of the University of California, 

Berkeley, California 

FIGURE 1. Map of the Gulf of California, with the Baja California 

peninsula to its west and mainland Mexico to the east. The area 

shown is the following: northern Gulf of California (dark shading) 

south to 28°N latitude (which is also the border between the Mexican states of Baja California and Baja California Sur), the southern 

Gulf of California (medium shading) to the Gulf’s entrance between 

Cabo San Lucas and Cabo Corrientes, and the Pacific Mexican 

coasts of the Baja California, Baja California Sur, and Jalisco (light 

shading).
NUMBER 96 • 3

US Alg. Coll. Algal Collection of the U.S. National Herbarium, National Museum of Natural History, 

Smithsonian Institution, Washington, D.C.

Several botanical and phycological references were invaluable 

throughout this study, notably the thorough AlgaeBase (http://

www.algaebase.org), a database of information on marine, terrestrial, and freshwater algae that was developed and is updated 

and maintained by Michael and Wendy Guiry (Guiry and Guiry, 

2007–2012); the second edition of Taxonomic Literature (referred 

to as TL-2) by Stafleu and Cowan (1976–1988) and its supplement

volumes (Stafleu and Mennega, 1992–2000; Dorr and Nicolson, 

2008, 2009); Stafleu (1972) on dates of publication of the extensive volumes of Engler and Prantl; Botanical Latin (Stearn, 2004); 

and Composition of Scientific Words (Brown, 1979). The citation 

of the authors of taxa names follows Brummitt and Powell (1992). 

FIGURE 2. Map of the northern Gulf of California, Mexico, showing most of the locales (algal collection sites).
4 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 3. Some of the northern Gulf of California collecting sites. A–D. Isla Ángel de la Guarda: A. Puerto Refugio, south shore, low tide 

(April 1977). B. Roca Blanca, near the middle of Puerto Refugio (April 1974). C. Puerto Refugio, intertidal rock platform around point on 

west shore. D. Expansive alluvial fan on the island, above the cliff fronting the intertidal shore of Puerto Refugio (April 1977). E. Estero, Punta 

Sargento, Sonora, low tide (high tide covers the darker sand area) (February 1973). F. Estero, Bahía de Las Ánimas, Baja California, exposed at 

low tide (note that high tide covers up to leaves and green of mangroves (May 1972). 
NUMBER 96 • 5

FIGURE 4. Desert coasts of the northern Gulf: A. Large cardón (Pachycereus pringlei), a cactus of the Sonoran Desert, on the shore near Punta 

Cheuca, Sonora (April 1976). B. Osprey flying in from the beach to add to its large nest of twigs, branches, and seaweeds—another seaweed 

collector in the northern Gulf, Punta Sargento, Sonora (February 1973). C. Low tide, showing intertidal habitats, Punta Willard, north of Bahía 

San Luís Gonzaga, Baja California (July 1973). D. Puerto Calamajue, Baja California (July 1973). 
6 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Place and locality names of the land-based collection sites 

and ship-based cruise stations that are used herein (Figures 1, 2) 

are from the U.S. National Oceanic and Atmospheric Administration (NOAA) charts 21008, 21014, 21120, 21124, 21141, 

21161, 21181, and 21182, Carta de Farod e Hidrografía de 

México F. H. 600, and the road, boating, and cruising sea guides 

to Baja California and the Gulf of California, particularly the 

work of Lewis (1971) and also Wheelock and Gulick (1975), 

Peterson (1998), Williams (2003), Cunningham (2004, 2006a, 

2006b), Breeding and Bansmer (2009), and Rains (2013). 

It is hoped this publication will encourage algal taxonomic 

and phylogenetic research as it makes available a taxonomic 

baseline for further biodiversity, marine botanical morphological 

and molecular systematics, and ecological investigations in the 

northern Gulf of California (Figure 2). Accurate identification of 

the marine algae is essential not only for molecular systematic 

and phylogenetic studies but also for ecological and conservation 

studies and ecosystem management of this biologically unique region. The taxonomic descriptions, particularly genera and species, 

presented herein are to be treated as hypotheses, and as such, it 

is encouraged that their taxonomic status will be tested using genetic molecular analyses and further morphological comparisons.

The biological uniqueness of the northern Gulf of California 

(Figures 3, 4, 6–8) is internationally recognized, and the islands 

FIGURE 5. Land-based diving operations: A. Research vehicle set up to carry scuba air compressor, tanks, and diving equipment; collecting, 

photographic, and camping gear; and food and water for four week land-based diving operation; on the road to dive and collecting sites at Punta 

Cirio (south of Puerto Libertad), Sonora (June 1973). B. Scuba air compressor station to refill tanks, Punta Granito, Sonora (February 1973). 

C, D. Marine botanists James Norris and Katina Bucher during a break between scuba dives, Punta Cirio (November 1973). E. Jim Norris (aka 

“Santiago rojo,” as named by the Seri) working with Armando Torres and Angelita Torres at the Seri village, El Desemboque de San Ignacio, 

Sonora (February 1974).
NUMBER 96 • 7

 FIGURE 6. Playa Estación, Puerto Peñasco, Sonora: A. Low tide (arrow marks high tide line), 

one of the two daily (semidiurnal) tides that exposes the vast caliche shell-hash tidal platform 

below Laboratorio de Biología Marina (University of Arizona and Universidad de Sonora). 

B. Katy Bucher surveying the tidal platform; 

note the large Cumpleaños Tide Pool near the 

old “Casa Garcia” (seen above the shore).
8 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 7. Punta Bufeo (about 3.2 km north of Bahía San Luís Gonzaga), one of the species-rich study sites on the east coast (Gulf coast) of Baja 

California. Comparison of the coverage of intertidal macroalgae using natural light (A, C) and with infrared photography (B, D), a nondestructive technique for identifying and quantifying algal coverage developed by M. Littler and Littler (1985). A, B. A rocky intertidal. C, D. Close-up 

of larger intertidal boulders. In each comparison, the contrasting natural light and infrared images show more extensive coverage using infrared 

by revealing the chlorophyll (in red colors) of the different algal species (photos by Diane Littler and Mark Littler).

FIGURE 8. (Opposite) Northern Gulf red algae: A. Dense clumps of epiphytic Jania capillacea covering Sargassum, Playa Estación, Puerto 

Peñasco (November 1973). B. Corallina and crustose corallines among Chondracanthus (blackish) and Colpomenia tuberculata and C. phaeodactyla; intertidal, Puerto Refugio, Isla Ángel de la Guarda (R/V Dolphin expedition, April 1974). C. Tacanoosca uncinata, a large specimen 

(scale of white ruler is 22.5 cm) of a species of economic potential, Bahía San Francisquito (May 1973). D. Chondracanthus squarrulosus (two 

on lower left) growing on crustose corallines, Puerto Refugio, Isla Ángel de la Guarda (M/V Makrele expedition, April 1969). E. Palisada 

paniculata, short growth form (note that the white tips indicate solar burn) that extensively covers the tidal platform, Playa Estación, Puerto 

Peñasco (July 1974). F. Porolithon sonorense, a crustose coralline endemic to the Gulf of California, on top of tidal platform, Playa Estación, 

Puerto Peñasco (November 1973). 
NUMBER 96 • 9
1 0 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

and protected areas of the Gulf of California are a UNESCO 

World Heritage Site (http://whc.unesco.org/en/list/1182/). Conservation of its ecosystems’ biodiversity is being provided by the 

several marine biosphere reserves, marine protected areas (for 

natural resources or flora and fauna), marine sanctuaries, and 

national marine parks in the Gulf of California (e.g., Case et al., 

2002; Sala et al., 2002; Cartron et al., 2005; Enriquez-Andrade 

et al., 2005; Lluch-Cota et al., 2007; Danemann and Ezcurra, 

2008; Brusca, 2010). It is increasingly important that we study 

the effects of climate change on seaweed communities and the 

ecosystem responses of primary productivity, species composition, and abundance to conserve and manage coastal ecosystems 

(Harley et al., 2012; Raven and Hurd, 2012).
PHYLUM RHODOPHYTA

Rhodophyta R. Wettstein, 1901:46. 

Rhodophycophyta Papenfuss, 1946:218.

Members of the phylum (division) Rhodophyta, or “red algae,” exhibit an extreme diversity of shapes, sizes, and forms, including unicells; coalescing cells; simple to 

branched pseudofilaments and uniseriate to multiseriate filaments; prostrate crusts; and 

erect, simple to branched terete, compressed or foliose forms that may be solid or hollow. 

In texture they can be soft and gelatinous or flaccid, semirigid, or cartilaginous or stony 

and hard (calcified). Many are considered to be beautiful, showing amazing branching 

patterns or cell arrangements and colors. In size the red algae can be microscopic, minute, or small to large, and some may be up to 3 meters or more in length (e.g., Porphyra; 

Guiry and Guiry, 2009–2011). Vegetative anatomy can be pseudofilamentous, filamentous, and nonfilamentous simple to complex forms of pseudoparenchymatous structure 

(Kylin, 1937, 1956; Dixon, 1973; Cole and Sheath, 1990). 

Worldwide in distribution from both poles to the tropics, red algae grow in a wide 

variety of habitats, from the high intertidal to the deep subtidal. Some members, for 

example, certain crustose coralline algae, have been recorded growing at depths of 286 

meters (927 feet) in tropical deepwater communities (Littler et al., 1985, 1986). The 

number of species of red algae is comparatively few at the poles and greatly increases in 

number and diversity toward the tropics. 

Members of the Rhodophyta were initially grouped together on the basis of biochemical characters, i.e., their red pigments (Harvey, 1853, as Rhodospermeae). The 

degree of red coloring is variable among the species, from pale rose to dark red, sometimes blackish red or even greenish red. This color variation is due to accessory pigments, 

the phycobiliproteins, phycocyanin, phycoerythin, and allophycocyanin (organized in 

phycobilisomes), that mask in varying degrees the photosynthetic green pigments, chlorophyll a and d (note: Larkum and Kühl, 2005, suggested that a cyanobacterium associated with red algae may be the source of chlorophyll d). The chloroplasts of red algae 

lack external endoplasmic reticulum and contain unstacked thalakoids. Energy reserves, 

primarily floridean starch and galactoside floridoside, are stored in the cytoplasm. Cell 

wall composition is variable among the species, containing a mixture of cellulose and 

noncellulose polysaccharides, such as glucans, xylans, and galactans. Polysulphate esters 

are characteristic components of the cell walls. Some species are lightly to heavily calcified. The calcium carbonate is in the mineral form of calcite in the Corallinales P. C. 

Silva et Johansen (1986), some of the Peyssonneliales Krayesky, Fredericq et J. N. Norris 

(in Krayesky et al., 2009), and the Rhodogorgonales Fredericq, J. N. Norris et Pueschel 

Red Algae
1 2 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

(in Fredericq and Norris, 1995) and in the form of aragonite in 

some of the Nemaliales F. Schmitz (1892).

All red algae lack flagellated reproductive stages and centrioles in their life histories (Garbary and Gabrielson, 1990). 

Asexual reproduction is by nonflagellated spores that are either 

produced by vegetative transformation of a cell or developed 

within a sporangium. The sporangia may produce monospores 

(a single spore), bispores (two spores), tetraspores (four spores), 

or polyspores (many spores). The mobility of spores by amoeboid 

action and by gliding has been described for some red algal species 

in different classes (e.g., Pickett-Heaps et al., 2001; Ackland et al., 

2007) and in the recently described “Acrochaetium-like” genus, 

Rhodachlya (West et al., 2008; Rhodachlyales, Rhodachlyaceae).

Sexual reproduction, varying from the relatively simple to 

highly specialized, characterizes the groups of red algae. Female reproductive structures in the Florideophyceae are differentiated into 

a carpogonial apparatus with a thread-like extension, the trichogyne. The one-celled carpogonium of the female reproductive apparatus becomes a zygote after fertilization. The zygote may divide 

to form carpospores or give rise to special filaments called gonimoblasts. Some or all of the cells of the gonimoblast develop into 

carposporangia. The mass of carposporangia, the gonimoblasts, 

and the specialized cell bearing them form the carposporophyte 

(diploid generation borne on the female gametophyte). Nonflagellate spermatia (male gametes) are produced by the spermatangia.

Remarks. Among the benthic marine algae, the Rhodophyta, with more than 42 orders, contains the greatest number of species. Currently, more than 6,500 species of red algae 

are known, but there actually may be more than 12,000 species 

(Woelkerling, 1990). Most of the known red algal species are 

marine, and very few—less than 3% (or about 150 species)—

are known from freshwater environments (Smith, 1950; Sheath, 

1984, 2003). Even fewer red algae are terrestrial. Some, such as 

Porphyridium cruentum (S. F. Gray) Nägeli (1849; basionym: Olivia cuenta S. F. Gray, 1821; =Porphyridium purpureum (Bory de 

Saint-Vincent) K. M. Drew et R. Ross, 1965) form a gelatinous, 

blood-red-colored layer on damp soil or wood or walls with calcareous material or brickwork (Sheath and Sherwood, 2002). 

One genus, Rufusia D. E. Wujek et Timpano (1986), is described 

from Costa Rica and Panama and is only known in sloth hairs.

Benthic marine red algae are ecologically important. Almost 

all red algae are primary producers, with the exception of the 

very few parasitic species, providing food, oxygen, and structural 

habitat for herbivorous and omnivorous micro- to macroinvertebrates and fish, herbivorous sea turtles, and Galápagos marine 

iguanas. Herbivorous marine mammals, the manatees and dugongs, also ingest red algal epiphytes while grazing on seagrasses. 

Crustose corallines and calcified peyssonnelioids are important 

components in the buildup of layers of biotic (coral) reef structure. Others, as free-living rhodoliths or maerl, are harvested in 

coastal regions or sometimes dredged, crushed, and used as fertilizers or soil conditioners in agriculture and gardening (see discussion of Corallinales herein). Some red algal species are harvested 

in the field or grown in mariculture or aquaculture to be used as 

human foods or are used by the phycocolloid medical or cosmetic 

industries for their natural products, including antioxidants, cytotoxins, and other bioactive compounds (see, e.g., Naylor, 1976; 

Dawes, 1987; Ohno and Critchley, 1993; Jones, 2008; Zubia et 

al., 2009; Tierney et al., 2010; see also discussion of Pyropia, 

Tacanoosca, Gelidiales, and Gracilariales herein). 

The Rhodophyta are one of the oldest groups of eukaryotic 

algae. Possible fossils of red algae may be from about 2 bya (billion years ago) (Tappan, 1976). The noncalcified, filamentous 

Bangiomorpha N. J. Butterfield (2000), which resembles the living species of Bangia, originated about 1.2 bya in the late Mesoproterozoic to early Neoproterozoic (Butterfield et al., 1990; 

Butterfield, 2000). It is generally accepted that the plastids of red 

(Rhodophyta), green (Chlorophyta), and “glaucophyte” algae 

share a common ancestry, having originated from a cyanobacterial 

endosymbiosis (Cavalier-Smith, 1986; Bhattacharya and Medlin, 

1995; Delwiche et al., 1995; Delwiche, 1999, 2007; Moreira et 

al., 2000; Bhattacharya et al., 2004; Rodríguez-Ezpeleta et al., 

2005; Yoon et al., 2006a, 2006b; Reyes-Prieto et al., 2007). The 

Rhodophyta is one of the three “primary” plastid-containing 

groups taxonomically classified within the kingdom Plantae

Haeckel, 1866 (Cavalier-Smith, 1998) or more recently considered to be within the Archaeplastida Adl et al. (2005, 2012). 

Pseudoparenchymatous red algae have been recognized 

and described from as early as the late Neoproterozoic, about 

600–550 mya (million years ago), and were apparently noncalcified when living (Xiao et al., 1998; Xiao and Knoll, 2000; 

Saunders and Hommersand, 2004). The simple pseudoparenchymatous red algae, such as Wengania (Zhang, 1989; Zhang et 

al., 1998), are among the earliest lineages near the base of the 

florideophytes, and the more complex pseudoparenchymatous 

species (e.g., Thallophyca) represent stem groups of the coralline algae (Johnson, 1960, 1961; Xiao et al., 2004). Calcifying 

red algae first appeared in the Paleozoic, 543–248 mya (Brooke 

and Riding, 1998), and coralline red algae appeared in the Early 

Cretaceous of the late Mesozoic, 144–65 mya, and through the 

Cenozoic, 65 mya to present (Arias et al., 1995; Aguirre et al.,

2000, 2010). Among the orders of class Florideophyceae, there 

is fossil evidence (Wray, 1977) that members of Corallinales may 

go back to the Cretaceous (130 mya), and the Peyssonneliales 

and Gigartinales diverged from the Late Jurassic (160 mya). 

Red algal taxonomists have followed and continuingly 

modified the classification system of Schmitz (1889, 1892) and 

Kylin (1956). It traditionally has been accepted that there were 

two major groups of red algae, the Bangiophyceae and Florideophyceae (e.g., Schaffner, 1922; Papenfuss, 1955; Silva et al., 

1996a; Abbott, 1999), with debate as to whether these groups 

should be classes or subclasses. For years the higher classification 

of the red algae remained in a state of flux (Dixon, 1973), with 

members of the Bangiophycidae considered to be polyphyletic 

(Müller et al., 2003, 2005b; Sutherland et al., 2011) and those of 

the Florideophycidae considered to be monophyletic (Gabrielson 

and Garbary, 1986, 1987; Garbary and Gabrielson, 1990).

More recently, three systems of higher classifications have 

been proposed on the basis of molecular, phylogenetic, and morphological analyses (e.g., Saunders and Hommersand, 2004; Adl 
NUMBER 96 • 1 3

et al., 2005, 2012; Yoon et al., 2006b). Saunders and Hommersand (2004) described the subkingdom Rhodoplantae G. W. 

Saunders et Hommersand with two phyla of red algae: (1) the 

Cyanidiophyta Moehn ex Doweld (2001), with a single class, 

Cyanidiophyceae Merola et al. (1981); and (2) the Rhodophyta 

to include three subphyla: Rhodellophytina Cavalier-Smith 

(1998), with the class Rhodellophyceae Cavalier-Smith (1998); 

Metarhodophytina (Magne) G. W. Saunders et Hommersand 

(2004), with the class Compsopogonophyceae G. W. Saunders 

et Hommersand (2004); and Eurhodophytina G. W. Saunders 

et Hommersand (2004), with the classes Bangiophyceae and 

Florideophyceae.

The major lineages of red algae proposed by Adl et al. 

(2005) in their system recognized the Rhodophyta as one of nine 

groups in the Archaeplastida. The Chlorophyta (“green algae”) 

and Embryophyta (Plantae; “land plants”) are within the Chloroplastida (Adl et al., 2012).

In a third system, Yoon et al. (2006b) considered the red 

algae to belong to a single phylum, the Rhodophyta, that contains two subphyla: (1) the subphylum Cyanidiophytina Yoon 

et al. (2006b), with a single class, the Cyanidiophyceae; and (2) 

a new subphylum, the Rhodophytina Yoon et al. (2006b), with 

six classes: Compsopogonophyceae, Stylonematophyceae Yoon 

et al. (2006b), Porphyridiophyceae Kylin (1937), Rhodellophyceae, Bangiophyceae, and Florideophyceae. Of these classes, the 

Bangiophyceae and Florideophyceae are herein treated as members of the subphylum Eurhodophytina.

Two of the three subphyla of the Rhodophyta are well represented in the northern Gulf of California: the Rhodophytina 

H. S. Yoon et al. with two of its classes; and the Eurhodophytina 

(Magne) G. W. Saunders et Hommersand, also represented by 

two of its classes. At present there are no members of the third 

subphylum, the Cyanidiophytina H. S. Yoon et al. known in the 

northern Gulf of California. 

KEY TO THE SUBPHYLA OF RHODOPHYTA IN THE NORTHERN GULF OF CALIFORNIA

1a. Algae uniseriate to multiseriate pseudofilaments (initially uniseriate then becoming multiseriate within a thick gelatinous 

matrix); or erect or prostrate filaments (not pseudofilaments); disc-shaped or cushion-like; life histories biphasic or 

triphasic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rhodophytina

1b. Erect to prostrate, uniseriate to multiseriate filaments; or narrow to broad sheet-like blades; or structurally more complex 

forms, pseudoparenchymatous anatomy; life histories triphasic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Eurhodophytina

PART I: SUBPHYLUM RHODOPHYTINA

Rhodophytina H. S. Yoon, K. M. Müller, Sheath, F. Ott, et D. Bhattacharya, 

2006b:490.

The subphylum Rhodophytina includes red algae that 

are unicellular, pseudofilamentous, or multicellular. Cells have 

plastids of various morphologies and associations with differing organelles. Life histories are unknown for many species, but, 

where known, are either biphasic or triphasic.

Remarks. Two classes of the Rhodophytina are represented in the Gulf of California.

KEY TO THE CLASSES OF RHODOPHYTINA IN THE NORTHERN GULF OF CALIFORNI

1a. Algae uniseriate to multiseriate pseudofilaments (initially uniseriate then becoming multiseriate, with cells separated from 

each other within a thick gelatinous matrix) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stylonematophyceae

1b. Algae erect or prostrate filaments (not pseudofilaments); disc-shaped or cushion-like; life histories biphasic . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Compsopogonophyceae

PART IA. STYLONEMATOPHYCEAE

Stylonematophyceae H. S. Yoon, K. M. Müller, Sheath, F. Ott et D. Bhattacharya, 2006b:490.

Class Stylonematophyceae includes red algae that are unicellular, pseudofilamentous, or filamentous. Cells have plastids 

of various morphologies, with or without a pyrenoid. Golgi are 

associated with mitochondria and endoplasmic reticulum. 

Asexual reproduction is by cell division or monospores.

Remarks. The class is currently composed of two 

orders: the Stylonematales, which is represented in the Gulf of 

California, and the more recent Rufusiales Zuccarello et J. A. 

West (in Zuccarello et al., 2008).

Stylonematales

Stylonematales K. M. Drew, 1956b:73.

Chrootheceales F. D. Ott, 2009:554.

The Stylonematales is a monotypic order, with the characteristics of the family.

Stylonemataceae

Stylonemataceae K. M. Drew, 1956b:73.

Chrootheceaceae F. D. Ott, 2009:555.

Goniotrichiceae G. M. Smith, 1933:120, nom. superfl. [see Silva, 1980: 

83].
1 4 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Algae of this family are usually uniseriate, simple to branched 

pseudofilaments; others may be multiseriate, branched pseudofilaments. Cells of the pseudofilaments are separate from each 

other within a conspicuous, thick gelatinous matrix. Growth is 

by intercalary cell divisions. Cells are variable in shape, ovoid, ellipsoid, or cylindrical, and uninucleate, with most having a single 

stellate chloroplast. Pit plugs are absent.

Asexual reproduction is by monospores and by direct metamorphosis of vegetative cells (with no apparent cell division) 

that function as spores and are released by dissolution or rupture of the enveloping gelatinous matrix. Sexual reproduction is 

unknown.

Two genera of the Stylonemataceae are reported in the 

northern Gulf of California. 

KEY TO THE GENERA OF THE STYLONEMATACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. False-branched pseudofilaments of several globose cells, blue-green to brownish, within a broad gelatinous sheath . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chroodactylon

1b. Irregularly branched, uniseriate or multiseriate, pseudofilaments of mostly rectangular, reddish cells within a comparatively narrower gelatinous sheath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Stylonema

Chroodactylon Hansgirg

Chroodactylon Hansgirg, 1885:14.

Asterocytis (Hansgirg) Gobi ex F. Schmitz, 1896:324.

Algae are false-branched pseudofilaments. Pseudofilaments 

are composed of oval or elliptical cells that are enclosed within a 

broad, gelatinous sheath. Cells are arranged in an irregular uniseriate manner. Cells are 3.0–16 μm in diameter, 6.0–20 μm in 

length. Each cell contains a blue-green stellate, chloroplast, and 

a prominent pyrenoid. There is usually one false branch about 

every 200 μm of length of the pseudofilaments.

Asexual reproduction is by fragmentation and by monospores. Sexual reproduction has not been found.

One species is reported in the northern Gulf of California.

Chroodactylon ornatum (C. Agardh) Basson

Conferva ornata C. Agardh, 1824:104.

Chroodactylon ornatum (C. Agardh) Basson, 1979:67, pl. IX: fig. 52; Stewart, 1991:61; Yoshida, 1998:426, fig. 3-1D; Sheath and Sherwood, 

2002:123; Brodie and Irvine, 2003:42, fig. 5.

Asterocytis ornata (C. Agardh) G. Hamel, 1924:451, figs. b–d; Tanaka, 

1944:79, figs. 1–2; Tanaka, 1952:11, fig. 6; Phạm-Hoàng, 1969:68, fig. 

2.2; Lewin and Robertson, 1971:236.

Hormospora ramosa Thwaites in Harvey, 1848b: pl. 213.

Chroodactylon ramosum (Thwaites) Hansgirg, 1885:19; Abbott and Hollenberg, 1976:283, fig. 225; Abbott, 1999:42, fig. 1A.

Goniotrichum ramosum (Thwaites) Hauck, 1885:517.

Asterocytis ramosa (Thwaites) Gobi ex F. Schmitz, 1896:314; HuertaMúzquiz and Garza-Barrientos, 1975:7; Huerta-Múzquiz and 

Mendoza-González, 1985:46; Mendoza-González and Mateo-Cid, 

1986:420; González-González et al., 1996:302.

Algae forming filamentous tufts, blue-greenish in color, up 

to 5 mm tall; pseudofilaments of false branches, 300 μm (or 

more) in length, mostly about 25 μm in diameter; cells oval to 

adaxially compressed, about 15–18 μm in diameter; within thick 

gelatinous sheaths, sometimes up to 1(–3) mm thick (description 

after Abbott and Hollenberg, 1976).

Sexual reproduction unknown.

Habitat. Epiphytic on Compsonema secundum f. 

terminalis; intertidal.

Distribution. Gulf of California: Segundo Cerro 

Prieto, Bahía Kino; Bahía de La Paz. Central Pacific: Hawaiian 

Islands. Eastern Pacific: California; Isla Socorro (Islas Revillagigedo). Western Pacific: Vietnam; Japan.

Type Locality. Lake Mälaren, bridge near Transberg, Stockholm, Sweden.

Remarks. Chroodactylon ornatum is a widely 

distributed epiphyte, found on submerged plants and algae in 

marine, brackish, and freshwater habitats (Womersley, 1994; 

Sheath, 2003). Lewin and Robertson (1971), on the basis of 

morphological changes correlated with different salinities in culture, questioned if the marine and freshwater inhabitants were 

one or more species. However, most since then have accepted 

them as a single species (e.g., Schneider and Searles, 1991; Womersley, 1994). 

Stylonema Reinsch

Stylonema Reinsch, 1875:40; Wynne, 1985b:502–503.

Algae are mostly microscopic or sometimes minute, 

consisting of cells embedded in a homogenous mucilaginous 

sheath that may be unbranched or pseudodichotomously to irregularly branched, uniseriate to multiseriate pseudofilaments, 

or some may form a monostromatic blade. Species are attached 

below by a typical cell or a slightly enlarged basal cell. Cells 

are usually quadrate with rounded corners, or occasionally oblong, and have a single stellate chloroplast with a large, central 

pyrenoid. Growth initially in the earliest stages of spore development may be apical, then becomes intercalary or diffuse as 

it grows.

Asexual reproduction occurs by transformation of the 

entire contents of vegetative cells into archeosporangia. Each 

archeosporangium releases a single archeospore (without a 

cell wall) by moving through the surrounding mucilaginous 

sheath or by dissolution of the sheath. Sexual reproduction is 

unknown. 

Remarks. Species of Stylonema are usually epiphytic 

or epizoic and are widely reported throughout temperate to tropical waters.

There are two species known in the Gulf of California. 
NUMBER 96 • 1 5

KEY TO THE SPECIES OF STYLONEMA IN THE NORTHERN GULF OF CALIFORNIA

1a. Pseudofilaments uniseriate below; above pseudofilament usually 1 cell (sometimes 2–3 cells) wide . . . . . . . . . . S. alsidii

1b. Pseudofilaments develop above a single basal cell becoming 2–6(–8) cells wide, usually with a single cell at the apex . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S. cornu-cervi

Stylonema alsidii (Zanardini) K. M. Drew

FIGURE 9A

Bangia alsidii Zanardini, 1839:136; 1841:217.

Stylonema alsidii (Zanardini) K. M. Drew, 1956b:72; Wynne, 1985b:503; 

Scagel et al., 1989:261; Mateo-Cid and Mendoza-González, 

1991:18; Stewart, 1991:61; Mateo-Cid and Mendoza-González, 

1992:19; Mendoza-González and Mateo-Cid, 1992:16; ServiereZaragoza et al., 1993a:484; Stout and Dreckmann, 1993:9; MateoCid and Mendoza-González, 1994b:38; Mendoza-González et al., 

1994:104; Bula-Meyer, 1995:32; Mendoza-González and MateoCid, 1996b:64, 83, pl. 1: fig. 2; Abbott, 1999:44, fig. 1B,C; L. 

Aguilar-Rosas et al., 2000:130, 137; Mateo-Cid et al., 2000:63; 

CONANP, 2002:140; L. Aguilar-Rosas et al., 2002:234; PachecoRuíz and Zertuche-González, 2002:467; Brodie and Irvine 2003:46, 

figs. 7, 8; Dreckmann et al., 2006:154; Mateo-Cid et al., 2006:55, 

62; R. Aguilar-Rosas et al., 2006a:53, fig. 2A,B; Pacheco-Ruíz et al., 

2008:205; Bernecker, 2009:CD-Rom p. 58.

Goniotrichum alsidii (Zanardini) M. Howe, 1914:75; Setchell and Gardner, 

1924:741; Setchell and Gardner, 1930:151; Taylor, 1945:132; Tanaka, 

1952:5, figs. 2, 3; Abbott and Hollenberg, 1976:280, fig. 222; Silva, 

1979:315; R. Aguilar-Rosas, 1982:84; Schnetter and Bula-Meyer, 

1982:108, pl. 9: fig. 1; Stewart and Stewart, 1984:142; Huerta-Múzquiz 

and Mendoza-González, 1985:46; Mendoza-González and Mateo-Cid, 

1985:28; Mendoza-González and Mateo-Cid, 1986:421; Santelices and 

Abbott, 1987:8; Salcedo-Martínez et al., 1988:83; Sánchez-Rodríguez 

et al., 1989:41; Dreckmann et al., 1990:27, pl. 4: fig. 2; Ramírez and 

Santelices, 1991:164; González-González, 1993:441; León-Tejera and 

González-González, 1993:496; Mateo-Cid and Mendoza-González, 

1994b:38; González-González et al., 1996:313; Riosmena-Rodríguez 

et al., 2005a:33; Fernández-García et al., 2011:65.

Goniotrichum elegans var. alsidii (Zanardini) Zanardini, 1873:457, pl. 96A.

Bangia elegans Chauvin, 1842:33.

Goniotrichum elegans (Chauvin) Zanardini, 1847: 249; Rosenvinge, 

1909:75, figs. 15, 16; Kylin, 1937:44, fig. 17A; Kylin, 1941:3; Smith, 

1944:161, pl. 35: figs. 1, 2; Dawson, 1953a:3; 1957c:13; 1961b:401; 

1962b:184, 229, fig. 38a, b; Dawson et al., 1964:30, pl. 2: fig. B; Dawson, 1966a:14; Dawson and Neushul, 1966:174; Huerta-Múzquiz and 

Tirado-Lizárraga, 1970:127; Garbary et al., 1980b:144; Pedroche and 

González-González, 1981:66; Stewart and Stewart, 1984:142; Santelices and Abbott, 1987:8; González-González et al., 1996:212.

Goniotrichum elegans (Chauvin) Le Jolis, 1863b:103; Kylin, 1925:6, fig. 

1a,b; Dawson, 1944a:251.

Stylonema elegans (Chauvin) V. May, 1965:352.

Thalli minute epiphytes, 0.5–2.0 mm tall; pseudofilaments 

uniseriate in lower portions, 12–15 μm in diameter, occasionally 

becoming 2–3 cells wide in upper portions, 15–30 μm in diameter; simple or irregularly branched; attached by a single basal 

cell. Cells up to 10 μm in diameter, closely arranged within the 

thick, hyaline, gelatinous matrix of the pseudofilament.

Asexual reproduction as described for genus; monospores 

about 10 μm in diameter. Sexual reproduction unknown.

Habitat. Epiphytic on various algae and sea grasses, 

including species of Ulva, Bryopsis, Cladophora, Hincksia, 

Sphacelaria, Sargassum, Amphiroa, Jania, Botryocladia, and

Branchioglossum; mid intertidal to shallow subtidal. 

Distribution. Gulf of California: El Tornillal 

(Gulfo de Santa Clara) to Cabeza Ballena; Mazatlán, Sinaloa to 

Jalisco. Eastern Pacific: northern British Columbia to Todos Santos, Baja California Sur; Isla Guadalupe; Isla María Magdalena 

(Islas Marías; Islas Tres Marías); Jalisco to Chiapas; Costa Rica; 

Panama; Colombia; Peru; Chile; Rapa Nui (Easter Island); Isla 

Juan Fernández. Central Pacific: Hawaiian Islands. Western Pacific: Japan.

Type Locality. Trieste, Gulf of Trieste (in northern 

part of the Adriatic Sea, near border with Slovenia), Italy.

Remarks. Stylonema alsidii, usually growing as an 

epiphyte on other algae or epizoic on invertebrates, is widespread in temperate to tropical regions. Dawson (1953a, as “G. 

elegans”) noted that some of the pseudofilaments of Gulf of California specimens of S. alsidii were occasionally, irregularly multiseriate in the lower portions, a condition not generally reported 

for the species elsewhere.

Stylonema cornu-cervi Reinsch

FIGURE 9B

Stylonema cornu-cervi Reinsch, 1875:40, pl. XV [Rhodophyceae]; Scagel et 

al., 1989:261; Yoshida, 1998:430, fig. 3-1H; Abbott, 1999:44, fig. 1D; 

Brodie and Irvine, 2003:49, fig. 9; R. Aguilar-Rosas et al., 2006a:55, 

fig. 3A–C.

Goniotrichum cornu-cervi (Reinsch) Hauck, 1885:519; Howe, 1914: 

76; Kylin, 1925:6, fig. 1c–e; Kylin, 1937:41, fig. 17B; Tanaka, 

1944:222, figs. 4, 5; Hollenberg, 1948:156; Tanaka, 1952:9, 

fig. 5; Dawson, 1961b:401; Dawson et al., 1964:30, pl. 63: fig. 

A; Dawson and Neushul, 1966:174; Abbott and Hollenberg, 

1976:280, fig. 223; Hawkes et al., 1978:101; Garbary et al., 

1981:146; Ramírez and Santelices, 1991:165; González-González 

et al., 1996:212.

Algae microscopic epiphytes; of pseudofilaments, irregularly pseudodichotomously branched, usually less than 1 mm 

tall, 15–100 μm in diameter; lower portions mostly uniseriate, 

above becoming 2–4 rows of cells (4–8 cells in cross section), 

narrowing to uppermost portion, usually with only a single cell 

at tip; attached by a distinctive basal cell, 6–9 μm in diameter 

by 10–14 μm long. Cells ovoid, 4–8 μm diameter; irregularly 

arranged within the thick, hyaline matrix of the pseudofilament. 

Asexual reproduction as described for genus. Monosporangia not observed in Gulf specimens. Sexual reproduction 

unknown.
1 6 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Habitat. Epiphytic on Anotrichium and Cladophora and probably other algae; shallow subtidal, 5–15 m 

depths. 

Distribution. Gulf of California: Punta Robinson 

(vicinity of Puerto Libertad). Eastern Pacific: northern British 

Columbia to Cabo Punta Banda (Bahía de Todos Santos), Baja 

California; Peru; Chile; Isla Juan Fernández. Central Pacific: Hawaiian Islands. Western Pacific: Japan.

Type Locality. Cres (northern island in Kvarner 

Gulf), Adriatic Sea, Croatia. 

Remarks. A new record for the Gulf of California, 

specimens of Stylonema cornu-cervi were found epiphytic on 

Anotrichium (JN-4836), and a Cladophora (JN-4819b) that was 

growing on Digenea simplex, both from Punta Robinson (east of 

Puerto Libertad), Sonora. 

PART IB. COMPSOPOGONOPHYCEAE

Compsopogonophyceae G. W. Saunders et Hommersand, 2004:1503.

The class Compsopogonophyceae includes red algae with 

cells in which there is a Golgi-endoplasmic reticulum association 

and plastids with encircling thylakoids. Reproductive monosporangia and spermatia are produced by divisions by a curved wall 

through normal vegetative cells. Carpogonia, where known, are 

formed by the direct transformation of a vegetative cell. Life histories, where known, are biphasic.

Remarks. Some of the members of the Compsopogonophyceae have lost the reproductive mode that is the accepted 

characteristic of this lineage (Nelson et al., 2003). However, as 

noted by Saunders and Hommersand (2004) this does not alter 

their overall taxonomic placement. 

FIGURE 9. Species of Stylonema. A. Stylonema alsidii: Habit showing branching pseudofilament with cells enclosed in gelatinous matrix, 

regularly arranged and mostly uniseriate (JN-4491b, epiphytic on Cladophora, US Alg. Coll. microscope slide 4268). B. Stylonema cornu-cervi: 

Pseudofilament mostly multiseriate, with disc-shaped cells loosely and irregularly arranged in a gelatinous matrix, note the single basal cell and 

single cell at tip (JN-4836, epiphytic on Anotrichium secundum, US Alg. Coll. microscope slide 4974). 
NUMBER 96 • 1 7

The class Compsopogonophyceae is represented by a single 

order in the Gulf of California. 

Erythropeltidales

Erythropeltidales Garbary, G. I. Hansen et Scagel, 1980b:149.

Algae are either crustose and discoid or erect and filamentous or erect and membranous. Species are found growing 

epi- and endophytic on various algae or sea grasses, epi- and 

endozoic on invertebrates, or saxicolous on rocks or other hard 

substratum. Structurally, the erect species are variable and may 

be (1) uniseriate to multiseriate filaments that are simple to irregularly branched, (2) membranous and saccate or ribbon-like 

and, although usually entire, some may be divided, or (3) prostrate and crustose, of uniseriate filaments that are irregularly 

branched that may tend to laterally coalesce. Cells have either 

a single stellate plastid or band- to cup-shaped parietal plastids 

and are with or without pyrenoids.

Asexual reproduction is by monospores that are cut off by 

an oblique or unequal curving wall through a vegetative cell. 

Sexual reproduction, where known, is by a carpogonium that 

is formed by direct transformation of a vegetative cell. Spermatia are produced by repeated divisions of vegetative cells by 

curved walls. 

Remarks. Zuccarello et al. (2011) proposed that the 

taxonomy of morphologically “simple” red algae—such as the 

Erythropeltidales, which can be difficult to distinguish—could be 

based on molecular studies.

One family occurs in the northern Gulf of California.

Erythrotrichiaceae

Erythrotrichiaceae G. M. Smith, 1933:120, 122; Smith, 1950:609 [see discussion of Silva et al., 1996a:912–915].

Erythropeltidaceae Skuja, 1939:33.

Algae of this family are entirely monostromatic, prostrate discs 

(Erythrocladia); partly prostrate with a basal disc and erect simple 

to branched filaments (Erythropeltis); crustose discs of radiating filaments that coalesce (Sahlingia); filamentous or ribbon-like to sheetlike (Erythrotrichia); or saccate and develop from a polystromatic 

disc that ruptures to form a monostromatic sheet (Porphyropsis).

Reproduction is by monospores that are divided from the 

vegetative cells by a curved wall.

Remarks. A few members of the Erythrotrichiaceae 

are ribbon-like or saccate to sheet-like, but only filamentous and 

discoid species have been reported in the Gulf of California.

There are five genera represented in the northern Gulf of 

California.

KEY TO THE GENERA OF ERYTHROTRICHIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli entirely prostrate (without erect filaments); either discoid (1 cell layer) or cushion-like (1–3 cell layers); composed 

of laxly coalesced or free (not adjoined) branched prostrate filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Thalli either a prostrate disc with erect filaments or erect and filamentous or ribbon-like, without a discoid portion . . . 3

2a. Irregularly shaped disc, with irregular margins; most marginal filaments not laterally coalesced; branching from submarginal cells; marginal cells not bifurcate; single parietal plastid with 1 central, usually irregular shaped pyrenoid . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Erythrocladia

2b. Compact disc shape of laterally coalesced filaments throughout; margins mainly entire; bifurcate marginal cells present; 

band-shaped or cup-shaped plastid, with circular pyrenoids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sahlingia

3a. Cells contain a single parietal plastid without pyrenoids; a few erect, free filaments above a distinct, discoid prostrate 

base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Erythropeltis

3b. Cells contain a stellate plastid with a single pyrenoid; free filaments above a discoid base or with free filaments attached 

by basal cells (without a discoid base) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Erect filaments above a discoid base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Porphyrostromium

4b. Erect filaments attached by rhizoids (without discoid portion); thalli uniseriate and cylindrical or becoming multiseriate 

and compressed or flattened and ribbon-like . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Erythrotrichia

Erythrocladia Rosenvinge

Erythrocladia Rosenvinge, 1909:71.

Algae are microscopic to minute; filaments develop and radiate outward from the original spore and become irregularly 

branched and laxly coalesced centrally into a monostromatic 

disc. Disc remains monostromatic throughout or becomes polystromatic and has margins that are more or less entire or irregular with some extending free filaments. Growth is apical and at 

the margins in early stages of development and later becomes 

diffuse. Cells have a single parietal plastid with one central pyrenoid. Pit plugs are not present. 

Asexual reproduction is by monospores and endospores. 

Monospores are formed by the division of a vegetative cell into 

two unequal portions, with the smaller developing into a sporangium. Asexual endospores are formed by repeated cleavage of a 

vegetative cell. Sexual reproduction is unknown.

There are two species of Erythrocladia reported in the Gulf 

of California, along with another somewhat similar discoid, 

prostrate epiphyte, a species of Sahlingia.
1 8 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

KEY TO THE SPECIES OF ERYTHROCLADIA AND SAHLINGIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Endophytic within cell walls of other algae; filaments spreading out irregularly, later may become coalesced near center 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Erythrocladia endophloea

1b. Epiphytic on other algae; filaments centrally coalesced into a prostrate disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Irregular-shaped disc; margins uneven, with extending, elongated marginal cells (mostly not coalescing), each with a 

rounded tip (not bifurcate) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Erythrocladia irregularis

2b. Disc shaped; margins more or less entire; filaments coalesced throughout; marginal cells mostly coalescing; marginal 

bifurcate cells present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sahlingia subintegra

Erythrocladia endophloea M. Howe

Erythrocladia endophloea M. Howe, 1914:81, pl. 30: figs. 1–7; Dawson et 

al., 1964:31, pl. 29: figs. G,H; Heerebout, 1968:143; Ramírez and Santelices, 1991:161; Schneider and Searles, 1991:180, fig. 212. 

Erythrocladia recondita M. Howe et Hoyt, 1916:112, pl. 12: figs 1–5, pl. 13: 

fig. 1; Huerta-Múzquiz and Mendoza-González, 1985:46; GonzálezGonzález et al., 1996:199.

Algae minute; primarily endophytic growing between cell 

walls of other algae and sometimes also partly epiphytic. Initially 

of irregularly branched prostrate filaments, tending to form an 

incomplete network; later cells in central portions may partly coalesce into irregular discs, up to 180 μm in diameter, remaining 

mostly monostromatic. Filaments branch laterally, subdichotomously or irregularly, mostly from subterminal cells and remain 

free outward. In surface view: outer cells of filaments variously 

shaped; cells toward center portion ovoid to irregularly angular; 

outward mostly elongated; 4.0–14 μm in diameter.

Monospores 4–5 μm in diameter (description after Howe, 

1914). 

Habitat. Endo-epiphytic on Halymenia and probably other macroalgae; intertidal to shallow subtidal. 

Distribution. Gulf of California: Bahía de Las 

Ánimas; La Paz. Eastern Pacific: Peru. 

Type Locality. On Leptocladia peruviana, dredged 

from 9 m depth; Bahía de Sechura, Departamento de Piura, 

northern Peru.

Remarks. Erythrocladia endophloea was recorded 

in the Gulf of California by Huerta-Múzquiz and MendozaGonzález (1985, as “E. recondita”). It is also tentatively identified in/on a blade of H. californica from Bahía de Las Ánimas 

(JN-3203b, US Alg. Coll. microscope slide 4251). 

Erythrocladia irregularis Rosenvinge

FIGURE 10A

Erythrocladia irregularis Rosenvinge, 1909:72, figs. 11, 12; Kylin, 1925:9, 

fig. 3A,B; Kylin, 1937:43, fig. 17C; Tanaka, 1944:93, fig. 14; Smith, 

1944:166, pl. 37: fig.1; Dawson, 1944a:251; Tanaka, 1952:77, 

fig. 37; Dawson, 1953a:5; 1961b:402; Heerebout, 1968:141, figs. 

1–4; Abbott and Hollenberg, 1976:284, fig. 226; Huerta-Múzquiz 

and Mendoza-González, 1985:46; Scagel et al., 1989:177; Stewart, 

1991:61; Mateo-Cid and Mendoza-González, 1991:18; Ramírez and 

Santelices, 1991:161; Mateo-Cid and Mendoza-González, 1992:19; 

González-González, 1993:441; Serviere-Zaragoza et al., 1993a:483; 

León-Tejera and González-González, 1993:496; Mateo-Cid et al., 

1993:46; Mateo-Cid and Mendoza-González, 1994b:38; MendozaGonzález et al., 1994:104; González-González et al., 1996:309, 389; 

Mendoza-González and Mateo-Cid, 1996b:65, 83, pl. 1: fig. 5; Yoshida, 1998:432, fig. 3-1I; CONANP, 2002:140 [as “Erythrotrichia 

irregularis”]; Dreckmann et al., 2006:154; Mateo-Cid et al., 2006:55, 

62; Pacheco-Ruíz et al., 2008:205; Zuccarello et al. 2010:366, fig. 3b–

g, tbls. 1, 2.

Algae epiphytic, discoid, monostromatic (rarely distromatic), 

up to 300 μm across; adhering directly to host. Irregularly shaped 

discs; composed of prostrate filaments coalesced only in central 

portion; outward with uneven margins of irregularly branched 

filaments, mostly free from one another. Cells in central portion, 

polygonal, up to 8 μm; cells of margins, 3–4 μm in diameter and 

longer than wide; pyrenoids mostly irregularly shaped.

Asexual reproduction by subspherical monosporangia, 

formed in central portion of disc. Sexual reproduction unknown. 

FIGURE 10. Species of Erythrocladia and Sahlingia. A. Erythrocladia irregularis: Prostrate disc with monospores (after Kylin, 1925: 

fig. 3a). B. Sahlingia subintegra: Prostrate disc with monospores

(after Kylin, 1925: fig. 3g, as Erythrocladia subintegra).
NUMBER 96 • 1 9

Habitat. Epiphytic on species of Chaetomorpha,

Dictyota and probably other algae; intertidal. 

Distribution. Gulf of California: Puerto Peñasco 

to Isla Turner (off SE end of Isla Tiburón); Isla Estanque (Pond 

Island); Bahía Concepción to Bahía de La Paz; Mazatlán, Sinaloa 

to Nayarit. Eastern Pacific: Alaska to Todos Santos, Baja California Sur; Oaxaca to Chiapas; Chile. Western Pacific: Japan; 

Korea.

Type Locality. Epiphytic on Polysiphonia urceolata; Møllegrund, about 0.8 km off Hirshals, Skagerrak, northern Denmark.

Remarks. Erythrocladia irregularis, the lectotype 

of the genus (Kylin, 1956), has sometimes been considered to 

be conspecific with Sahlingia subintegra (e.g., Heerebout, 1968; 

Garbary et al., 1981, both as Erythrocladia subintegra). Morphologically E. irregularis differs primarily from S. subintegra in 

being irregular-discoid in shape, the result of having free (noncoalesced) marginal filaments that develop an irregular margin. 

Kornmann and Sahling (1985) and Kornmann (1989) also used 

development of the disc to further separate the two genera, with 

the early development of Sahlingia being a four-celled stage and 

a more regular disc shape with even margins.

Erythropeltis F. Schmitz

Erythropeltis F. Schmitz, 1896:313.

Algae epiphytic or epizoic; a prostrate monostromatic disc, 

with or without a few, short erect filaments. Growth from marginal cells. Cells irregularly arranged within disc; with a single 

parietal plastid. Monosporangia formed by oblique wall within 

a vegetative cell.

Remarks. Erythropeltis is apparently a monotypic 

genus. Schmitz (in Schmitz et Hauptfleisch, 1896) originally described the genus as only being discoid (without erect filaments), 

having apparently overlooked the study of Berthold (1882a, 

1882b), who had earlier described the generitype, Erythrotrichia 

discigera, as a disc with erect filaments (see also Batters, 1900; 

Rosenvinge, 1909; Silva et al., 1996a). Specimens identified as 

Erythropeltis discigera were cultured by Kornmann (1984) and 

Kornmann and Sahling (1985) and were found to have a heteromorphic life history of filamentous and discoid phases, which were 

both reproduced by monospores. Although Erythropeltis discigera

is generally accepted as a species, it may be involved in the life history of Porphyrostromium ciliare (Brodie and Irvine, 2003). Further study is needed to clarify the generic status of Erythropeltis.

There is one species of Erythropeltis reported in the northern Gulf of California. 

Erythropeltis discigera (Berthold) F. Schmitz

Erythrotrichia discigera Berthold, 1882a:511; Berthold, 1882b:25, pl. 1: figs. 

15–18; Kylin, 1937:44, fig. 19A–C.

Erythropeltis discigera (Berthold) F. Schmitz, 1896:313, fig. 195; Dawson, 

1944a:252; 1953a:6; 1961b:401; González-González et al., 1996:199; 

Brodie and Irvine, 2003:61.

Algae epiphytic; prostrate and discoid; spreading, up to 300 

μm across; margins irregular; either without erect filaments or 

with a few short, erect filaments arising from the central portion of disc. Discoid portion monostromatic to polystromatic, of 

mostly polygonal cells, each with a single parietal plastid.

Monosporangia globose, cut off from originating cell by an 

oblique wall.

Habitat. Epiphytic on Sphacelaria and probably on 

other algae; intertidal.

Distribution. Gulf of California: Isla Tiburón 

(Islas de la Cintura). 

Type Locality. Epiphytic on Cystoseira compressa; Gulf of Naples, southwest coast of Italy, Tyrrhenian 

Sea, Italy.

Remarks. The taxonomic status of Erythropeltis 

discigera is somewhat uncertain. Batters (1900) suggested 

Erythrotrichia discigera Berthold, the generitype of the genus 

Erythropeltis, may be a synonym of Bangia ciliaris Carmichael 

ex Harvey (in W. J. Hooker, 1833). Later, Erythropeltis discigera was also used as the type for another genus, Erythrotrichopeltis Kornmann (1984). Taxonomically, Kornmann (1984) 

also considered it conspecific with Bangia ciliaris Carmichael 

ex Harvey, making the combination Erythrotrichopeltis ciliaris

(Carmichael) Kornmann (which is now Porphyrostromium ciliare (Carmichael ex Harvey) M. J. Wynne, 1986). Others have 

kept Erythropeltis and Porphyrostromium separate (e.g., Furnari et al., 2003), and Brodie and Irvine (2003), although recognizing Erythropeltis discigera as a distinct species, noted it may 

possibly be part of the life history of Porphyrostromium ciliare. 

Comparative morphological, molecular, and culture studies are 

needed on type locality Erythropeltis discigera and the Gulf of 

California E. discigera to elucidate their taxonomic status and 

possible relationship to P. ciliare.

Erythrotrichia Areschoug

Erythrotrichia Areschoug, 1850:435.

Algae are minute, erect, filaments that are uniseriate 

throughout, uniseriate only in the lower portion and multiseriate above, or multiseriate, flattened, and ribbon-like. They are 

unbranched or occasionally branched and attached by rhizoids 

from a basal cell or basal cells. Growth is usually apical in the 

initial stages of development and then becomes intercalary and 

diffuse. Each cell has a single, stellate plastid with a central pyrenoid. Pit plugs are absent.

Asexual reproduction is by monospores. An oblique wall 

is formed within the parent cell, dividing it into two unequalsized cells; the smaller portion becomes the monosporangium 

that releases a single monospore. Sexual reproduction, where 

known, is by a three-celled gametophyte, with the apical cell initially producing a spermatangium by oblique division. Following 

the release of a single, very small, pale spermatium, the remaining contents of the apical cell differentiate into a carpogonium. 

Upon contact with a spermatium, the carpogonium fuses and 
2 0 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

develops a zygote that germinates directly on the gametophyte 

and develops a linear series of diploid cells that, in turn, produce 

monosporangia. Meiosis is likely somatic, occurring at the time 

of monospore germination.

Remarks. Species of Erythrotrichia are minute, 

often microscopic algae, and are usually epiphytic on various larger algae or sea grasses. Acknowledging the difficulity 

of separating these morphologically simple species, Zuccarello 

et al. (2010; 2011) noted future descriptions should include 

molecular and morphological data from standardized culture 

conditions.

There is one species in the southern Gulf, Erythrotrichia ascendens E. Y. Dawson (1953a), an epiphyte on Galaxaura, described from a beach approximately 8.05 km [5 miles] north of 

Cabo Pulmo, Baja California Sur.

Four other species of Erythrotrichia, including one with two 

taxonomic forms (forma), are currently known from the northern Gulf of California.

KEY TO THE SPECIES OF ERYTHROTRICHIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Filaments cylindrical throughout; attached by a single basal cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Filaments cylindrical, compressed or flattened; attached by branched rhizoidal processes from lowermost basal cell . . . 4

2a. Lowermost basal cell elongated and tapering downward; penetrating cortical cells of algal host . . . . . . . . . E. biseriata

2b. Lowermost basal cell lobed (not tapered) at point of attachment on surface of algal host (not penetrating host) . . . . . 3

3a. Filaments up to 3 mm long, 12–30 μm in diameter; monosporangia small, 5.0–10 μm in diameter . . . E. carnea f. carnea

3b. Filaments shorter and narrower, mostly less than 1 mm long and 9.0–12 μm in diameter; monosporangia slightly larger, 

about 12 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. carnea f. tenuis

4a. Cylindrical in lower portion and broadening in upper portion, up to 4(–8) rows of cells wide, with cells in transverse 

rows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. tetraseriata

4b. Mostly cylindrical throughout; only 1–2 cells wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . E. parksii var. minor

Erythrotrichia biseriata Tak. Tanaka

FIGURES 11, 12A–C

Erythrotrichia biseriata Tak. Tanaka, 1944:86, fig. 8A–G; 1951:98; 1952:17, 

fig. 8A–G; Dawson, 1953a:7; 1954a:4; 1961b:401; Huerta-Múzquiz 

and Tirado-Lizárraga, 1970:127; Kajimura, 1979:98; León-Tejera and 

González-González, 1993:496; González-González et al., 1996:200, 

390; Serviere-Zaragoza et al., 2007:9 [as “Erythrotrichia carnea.”]

Algae epiphytic, unbranched, more or less erect filaments, 

1–2 mm long, 10–26 μm diameter; attached by a lowermost 

basal cell penetrating cortical cells of algal host. Filaments initially uniseriate and remaining so in lower portions; later can become 2 cells wide by longitudinal divisions in portions of upper 

thallus (appearing more or less biseriate). Cells of filaments 

within gelatinous matrix, about 3–4 μm thick; cells usually not 

as long as wide, more or less quadrate with rounded corners; 

8–15 μm long by 10–22 μm in diameter; chloroplast stellate with 

a central pyrenoid. Lowermost basal cell distinctive from above 

cells; elongated and more slender, tapering downward, 25 μm in 

length and 8 μm in diameter.

Asexual reproduction by ovate monospores, 6–8 μm by 

5–7 μm; apparently cutoff laterally (see Tanaka, 1944: fig. 8G). 

Sexual reproduction unknown.

Habitat. Epiphytic on Colpomenia, Halymenia, and 

Tacanoosca uncinata; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Libertad; 

Bahía de Las Ánimas; Ensenada de San Francisco; Mazatlán. 

Eastern Pacific: Isla San Benedicto (Islas Revillagigedo); Baja 

California to Oaxaca. Western Pacific: Japan; Taiwan.

Type Locality. Hachijō-jima (Hatidyō Island), Izu 

islands, south of Tokyo, Japan. 

Remarks. Erythrotrichia biseriata was listed as a 

synonym of E. carnea by Yoshida (1998) but without comment. 

FIGURE 11. Erythrotrichia biseriata: Developing filament (not yet 

biseriate) with the characteristic, penetrating linear-elongate basal 

cell (arrow) (JN-3203c, epiphytic on Halymenia, US Alg. Coll. microscope slide 4251). 
NUMBER 96 • 2 1

However, the species appears to be distinctive. The Gulf specimens referred to E. biseriata are apparently developing juveniles, 

with the characteristic long basal cell, that have not yet become 

two cells wide in the upper portions (see Tanaka, 1944: fig. 8F). 

Erythrotrichia carnea (Dillwyn) J. Agardh

Conferva carnea Dillwyn, 1807:54, pl. 84.

Erythrotrichia carnea (Dillwyn) J. Agardh, 1883:15, pl. 19; Kylin, 1937:43, 

fig. 18B–D; Smith, 1944:164, pl. 35: figs. 3–7; Dawson, 1944a:252; 

Tanaka, 1944:92, fig. 13A; 1951:97, fig. 1A–D; 1952:14, fig. 7A; Dawson, 1953a:10; 1957c:13; 1959d:4; 1961b:401; 1962b:170, 229, fig. 6; 

1963c:5; 1966a:14; Dixon and West, 1967:253, fig. 1A–D; Heerebout, 

1968:151, figs. 5–11, 14–18; Huerta-Múzquiz and Tirado-Lizárraga, 

1970:127; Norris, 1973:8; Huerta-Múzquiz and Garza-Barrientos, 

1975:7; Abbott and Hollenberg, 1976:286, fig. 228; Silva, 1979:315; 

R. Aguilar-Rosas, 1982:84; Stewart and Stewart, 1984:142; HuertaMúzquiz and Mendoza-González, 1985:46; Santelices and Abbott, 

1987:8; Salcedo-Martínez et al., 1988:83; Sánchez-Rodríguez et al., 

1989:41; Dreckmann et al., 1990:27, pl. 4: fig. 1; Rocha-Ramírez 

and Siqueiros-Beltrones, 1991:26; Ramírez and Santelices, 1991:163; 

Mateo-Cid and Mendoza-González, 1991:18; González-González, 

1993:441; Serviere-Zaragoza et al., 1993a:483; León-Tejera and 

González-González, 1993:496; Mendoza-González et al., 1994:105; 

R. Aguilar-Rosas and Aguilar-Rosas, 1994:519; Bula-Meyer, 1995:32; 

González-González et al., 1996:309; Anaya-Reyna and RiosmenaRodríguez, 1996:864, tbl. 1; Mendoza-González and Mateo-Cid, 

1996b:65, 83; Hoffman and Santelices, 1997:200, fig. 50(1–4); Yoshida, 1998:433; Abbott, 1999:45, fig. 1E; L. Aguilar-Rosas et al., 

2000:130, 137; Mateo-Cid et al., 2000:63; CONANP, 2002:140; 

León-Tejera and González-González, 2000:327, 329, 330; RiosmenaRodríguez et al., 2005a:33; 2005b:102; Dreckmann et al., 2006:154; 

Mateo-Cid et al., 2006:50, 55, 62; Serviere-Zaragoza et al., 2007:9; 

Bernecker, 2009:CD-Rom p. 58; Fernández-García et al., 2011:61.

Conferva ceramicola Lyngbye, 1819:144, pl. 48D.

Erythrotrichia ceramicola (Lyngbye) Areschoug, 1850:435.

Algae epiphytic; unbranched, uniseriate filaments, 1–2(–3) 

mm long and 12–27 μm in diameter; attached by lowermost basal 

cell (narrower than above cells) with short lobes or with short 

rhizoidal outgrowths. Cells of filaments, as long as wide or tending to be longer than wide, 14–30 μm in length and 12–27 μm 

in diameter; possess a stellate plastid with large central pyrenoid. 

Asexual reproduction by monosporangia cut off by oblique 

division at distal end of cell; monospores 5–10 μm in diameter. 

Sexual reproduction unknown. 

Habitat. Epiphytic on various algae, including species of Chaetomorpha, Phyllodictyon, Dictyota, Sphacelaria, Padina, Amphiroa, Corallina, Gelidium, Gelidiopsis, Botryocladia, 

and Anotrichium; intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Punta Los Frailes; Mazatlan, Sinaloa to Jalisco. Eastern Pacific: Alaska to Chiapas; Isla Guadalupe; Isla San Benedicto 

(Islas Revillagigedo); Clipperton Island; Costa Rica; Colombia; 

Galápagos Islands; Peru; Chile; Rapa Nui (Easter Island; Isla de 

Pascua); Isla Juan Fernández. Central Pacific: Hawaiian Islands. 

Western Pacific: Japan; Korea. 

Type Locality. Epiphytic on other algae; mouth of 

Loughor River, Glamorganshire (Loughor), Wales, United Kingdom (Brodie and Irvine, 2003:67) (epitype: Port Eynon, Gower, 

Wales [Zuccarello et al., 2011:635]). 

Remarks. In the upper Gulf of California, Erythrotrichia carnea has been reported on numerous host algal species (e.g., Mateo-Cid et al., 2006). Dawson (1966a) observed E. 

carnea to be mostly growing on deteriorating older algae in the 

vicinity of Puerto Peñasco. 

Culture studies and molecular analysis of Zuccarello et al. 

(2011) yielded seven separate lineages of E. carnea, one of which 

(lineage 2) was close to the type locality and designed as an epitype. Although the other lineages could represent new genera, 

because of their simple morphologies they could not be separated, and Zuccarello et al. (2011) suggested they could be identified on the basis of their genetic and phylogenetic differences.

Erythrotrichia carnea f. tenuis Tak. Tanaka

FIGURE 12D,E

Erythrotrichia carnea f. tenuis Tak. Tanaka, 1944:92, fig. 13B–E; 1951:98; 

1952:16, fig. 7B–E; Dawson, 1953a:10; Kajimura, 1979:98; GonzálezGonzález et al., 1996:200.

Algae epiphytic; composed of simple, unbranched, uniseriate filaments, up to 1.0 mm long and 9–12 μm wide. Cells 

FIGURE 12. Species of Erythrotrichia. A–C. Erythrotrichia biseriata: A. Part of a filament with monosporangia. B. Basal portion of 

young filament with elongate basal cell. C. Upper part of biseriate 

filament (A–C after Tanaka, 1952: fig. 8E, F, H). D, E. Erythrotrichia carnea f. tenuis: D. Basal portion of young filament. E. Mature filament with monosporangia (D, E after Tanaka, 1944: fig. 13).
2 2 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

slender, of varying lengths, mostly squarish to elongate, with 

rounded corners, 9–20(–30) μm long and 9–12 μm in diameter; 

have a stellate plastid with a pyrenoid.

Monosporangia more or less spherical, about 12 μm in 

diameter.

Habitat. Epiphytic on Chaetomorpha, Padina, and 

Gelidium; intertidal.

Distribution. Gulf of California: Cabo Pulmo. 

Eastern Pacific: Isla Guadalupe; Punta Santa Rosaliita (“Punta 

Santa Rosalía”), Baja California; Guerrero. Western Pacific: 

Japan.

Type Locality. Several syntype localities were 

listed by Tanaka (1944:92–93): “Ponape (Caroline Islands); 

Garanbi (Taiwan); and in Japan, Yonakuni Is. (Okinawa Pref.), 

Makurazaki (Satuma Prov.), Takamatu (Sanuki Prov.), Fukae 

(Gotō Islands), and Hinomisaki (Izumo Prov.).”

Remarks. Dawson (1953a) noted that most of the 

Mexican specimens, with filaments of smaller size and slender 

proportions, were in agreement with Erythrotrichia carnea f. 

tenuis Tak. Tanaka. Although known in the southern Gulf, its 

Gulf distribution is probably more widespread. Other Gulf records as “E. carnea” should be molecularly compared to the 

Japanese E. carnea f. tenuis, and their taxonomic status needs to 

be further evaluated.

Erythrotrichia parksii var. minor N. L. Gardner

FIGURE 13

Erythrotrichia parksii N. L. Gardner var. minor N. L. Gardner, 1927a:239, 

pl. 24: figs. 6, 7; Scagel, 1957:125; Dawson, 1961b:401; Thom et al., 

1976:271; Hawkes et al., 1978:100.

Algae epiphytic; erect filaments, up to 4 mm tall and 15–20 

μm in diameter; attached by irregularly branched rhizoids from 

basal cell. Individual filaments more or less same diameter 

throughout; composed of cells more or less quadrate, varying 

in height (length) from much shorter to slightly taller than wide. 

Cells with a band-shaped chloroplast.

Monosporangia formed from vegetative cell.

Habitat. Epiphytic on Colpomenia tuberculata and 

likely other algae; mid to low intertidal. 

Distribution. Gulf of California: Punta Pelícano, 

vicinity of Puerto Peñasco. Eastern Pacific: northern British Columbia to Washington. 

Type Locality. Epiphytic on Cryptosiphonia; Neah 

Bay, Washington, USA. 

Remarks. A new record for the Gulf of California,

specimens (JN-5037, US Alg. Coll. slide 4276) from Puerto 

Peñasco generally agree with the description of Erythrotrichia 

parksii var. minor N. L. Gardner (1927a). Although smaller in 

length, the Gulf E. parksii var. minor is similar in diameter and 

has the characteristic monosporangia. Some structures interpreted as “female gametangia (?)” in the type material by Gardner (1927a) may possibly be “female” filaments with fertilization 

tubes (protoplasmic prolongations) that were also observed in 

our Puerto Peñasco specimen (Figure 13A–C). Erythrotrichia 

parksii var. minor had been considered to be conspecific with E. 

carnea (Desikachary et al., 1990), but for now the two are recognized to be morphologically distinct until needed culture and 

molecular studies can assess their relationship. 

Erythrotrichia tetraseriata N. L. Gardner

FIGURE 14

Erythrotrichia tetraseriata N. L. Gardner, 1927a:240; Dawson, 1953a:12, 

pl. 1: fig. 5; 1961b:402; Dawson and Neushul, 1966:174; Abbott and 

Hollenberg, 1976:287, fig. 232; Pedroche and González-González, 

1981:66; Pacheco-Ruíz and Aguilar-Rosas, 1984:71, 76; L. AguilarRosas et al., 1985:125; Huerta-Múzquiz and Mendoza-González, 

1985:48; Serviere-Zaragoza et al., 1993a:483; R. Aguilar-Rosas and 

Aguilar-Rosas, 1994:519; González-González et al., 1996:200, 390, 

fig. 27.

Erythrotrichia californica Kylin, 1941:3, fig. 1A–D; Smith, 1944:165, pl. 36: 

figs. 4, 5; Dawson, 1944a:252; 1953a:8, pl. 1: fig. 1A–D; 1961b:401; 

Dawson and Neushul, 1966:174; González-González et al., 1996:200; 

Pacheco-Ruíz and Zertuche-González, 2002:467.

Algae epiphytic, unbranched filaments, 1.0–2.0(–4.0) mm 

long, attached below by short, branched rhizoidal cells. Filaments uniseriate in lower portions, 12–14 μm in diameter; upper 

portions 20–40 μm in diameter, multiseriate, of 4 or more cells; 

produced by successive longitudinal divisions. Cell shape slightly 

variable, usually shorter than wide; chloroplasts band(?) shaped.

Asexual reproduction by monosporangia. Monosporangia 

are cut off from cells in upper parts of filaments. Sexual reproduction unknown.

FIGURE 13. Erythrotrichia parksii var. minor: A–C. Portions of 

long unbranched, presumably female filament, some cells with “fertilization tubes” (JN-5037, US Alg. Coll. microscope slide 4276). 
NUMBER 96 • 2 3

Habitat. Epiphytic on Sphacelaria and Cladophora

and probably other algae; low intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de Los Ángeles; La Paz; Nayarit to Jalisco. Eastern 

Pacific: central California to Isla Magdalena, Baja California; 

Guerrero. Western Pacific: Korea.

Type Locality. Epiphytic on Zostera marina; San 

Pedro, Los Angeles County, southern California, USA.

Remarks. Although Erythrotrichia tetraseriata was 

considered conspecific with E. carnea by Desikachary et al. 

(1990), on the basis of morphological differences it is retained 

herein as a distinct entity until its taxonomic status can be evaluated by culture and molecular studies. 

Porphyrostromium Trevisan

Porphyrostromium Trevisan, 1848:100; Drew and Ross, 1965:97; Wynne, 

1986:328–329.

Erythrotrichopeltis Kornmann, 1984:208.

Algae are composed of minute erect, filaments, only a few 

millimeters long, that arise from a prostrate, monostromatic, 

discoid base. Filaments are unbranched, initially uniseriate and 

cylindrical, but may become multiseriate and compressed to flattened, with cells in more or less longitudinal rows. Cells have 

a plastid, are without pit plugs, and are with or without a pyrenoid. Growth is diffuse throughout the thallus, although it is 

apparently apical during initial development. 

Life histories are heteromorphic, with an erect phase (hair-like 

filaments) and a prostrate discoid phase. Asexual reproduction is 

by monospores, which develop by an unequal division (cytokinesis) of a vegetative cell. Monosporangia can be produced in both 

the erect filaments or prostrate discs. Gametophytes are monoecious with reproductive structures developed in the erect filaments. 

Carpogonia are formed with short trichogynes. After fertilization 

each carpogonium forms a zygosporangium that releases a single 

zygospore. Upon germination, it grows into the prostrate disc, 

which subsequently produces the erect hair-like filaments. Meiosis 

is presumably somatic. Spermatangia are formed by unequal division of vegetative cells, in which the smaller of the two resulting 

cells becomes a spermatangium that releases a single spermatium. 

Remarks. Findings of Zuccarello et al. (2011) supported Porphyrostromium as a distinct genus, and they proposed 

that their taxonomy be based on molecular and culture studies. 

KEY TO THE SPECIES OF PORPHYROSTROMIUM AND ERYTHROPELTIS 

IN THE NORTHERN GULF OF CALIFORNIA

1a. Disc prostrate, monostromatic throughout (up to 300 μm in diameter); without or with erect, short, unbranched filaments from central portion of disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Erythropeltis discigera

1b. Disc prostrate, monostromatic to pseudoparenchymatous; with erect, usually longer, unbranched filaments that are either 

cylindrical to compressed or flattened and ribbon-like . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Filaments cylindrical (uniseriate) becoming compressed above (2–4 cells wide) . . . . . . . . . . . Porphyrostromium ciliare

2b. Filaments initially uniseriate, broadening and becoming flattened, ribbon-like (4–8 cells wide) . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Porphyrostromium boryanum

FIGURE 14. Erythrotrichia tetraseriata: A, B. Portion of mature filaments seen with sporangia. C. Young filament with 

attaching cells. D. Basal portion with multicellular attachment structure (A–D after Kylin, 1941: fig. 1A–D, as Erythrotrichia californica).
2 4 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Porphyrostromium boryanum (Montagne) P. C. Silva

FIGURE 15A,B

Porphyra boryana Montagne, 1846b:150, pl. 3: fig. 2; Silva, 1952:300; Ardré, 1970:179, pl. 4: figs. 10, 11 [portion of Montagne’s type specimen].

Porphyrostromium boryanum (Montagne) P. C. Silva in Silva et al., 

1996a:914; Zuccarello et al., 2011:634, fig. 3e–h.

Porphyrostromium boryi (Montagne) Trevisan, 1848:100, nom. illeg. [see 

Silva in Silva et al. 1996a:914].

Erythrotrichia boryana (Montagne) Berthold, 1882b:25; Dawson, 1953a:7; 

1961b:401; Heerebout, 1968:150, fig. 13; Garbary et al., 1980b:155; 

Stewart and Stewart, 1984:142; González-González et al., 1996:200.

Erythrotrichopeltis boryana (Montagne) Kornmann, 1984:221.

Algae small prostrate discs, up to 3 mm in diameter, epiphytic on flat portions or encircling cylindrical portions of small 

algae. Disc monostromatic to pseudoparenchymatous, with irregular margins. A few short filaments projecting above the 

surface of the discoid portion. Filaments initially uniseriate, 

broadening and becoming flattened, ribbon-like above, mostly 

4–18 cells wide (90–170 μm in width). Cells of disc irregularly 

arranged; polygonal, with a single parietal plastid.

Monosporangia globose. Sexual reproduction unknown.

Habitat. Epiphytic on other algae.

Distribution. Gulf of California: Puerto Peñasco. 

Eastern Pacific: Isla Guadalupe; southern British Columbia to 

Bahía Asunción, Baja California; Peru. 

Type Locality. On Gelidium corneum; Fort des 

Anglais, Algeria (Ardré, 1970).

Remarks. Porphyrostromium boryanum is not well 

known in the northern Gulf. Culture studies of Zuccarello et al. 

(2011) showed that mature flat thalli of P. boryanum can be considerabily larger, up to 4 mm wide and 1–3 cm in length. Silva (in 

Silva et al. 1996a:914) noted the correct name is P. boryanum, 

and that “boryi and boryana are two distinct epithets rather than 

orthographic variants” and not correctable to “P. boryana” (as 

done by Wynne, 1986; Scagel et al., 1989).

Porphyrostromium ciliare (Carmichael ex Harvey) M. J. Wynne

FIGURE 15C

Bangia ciliaris Carmichael ex Harvey in W. J. Hooker, 1833:316. 

Porphyrostromium ciliare (Carmichael ex Harvey) M. J. Wynne, 1986:329; 

Zuccarello et al., 2011: fig. 3a-d.

Erythrotrichopeltis ciliaris (Carmichael ex Harvey) Kornmann, 1984:208.

Erythrotrichia ciliaris (Carmichael ex Harvey) Thuret, 1854:387–389; Thuret in Le Jolis, 1863a: Exsiccate No. 188 [see Sayer, 1975:357]; Thuret 

in Le Jolis, 1863b:103. 

Erythrotrichia ciliaris (Carmichael ex Harvey) Batters, 1900:374; Dawson, 

1953a [in part]:10, pl. 1: fig. 2; 1961b:401; González-González et al., 

1996:200.

Algae microscopic prostrate discs, up to 350 μm in diameter; 

epiphytic on other compressed to flat algae or encircling some cylindrical small algae. Disc monostromatic to pseudoparenchymatous; with irregular margins; with few short filaments projecting 

above surface of the prostrate portion; filaments initially uniseriate 

in lower portion, 15–20 μm in diameter, above (distally) becoming 

2–4 cells wide, 30–40 μm in diameter. Cells of disc irregularly arranged; polygonal, with a single plastid and a pyrenoid. 

Monosporangia globose. Sexual reproduction unknown.

Habitat. Epiphytic on and encircling filaments of 

Sphacelaria; intertidal.

Distribution. Gulf of California: Isla Tiburón. 

Eastern Pacific: British Columbia to Punta Banda, Baja California; Isla Cedros (off central Baja California); Peru. 

Type Locality. Epiphytic on Zostera; Appin, Argyll, Scotland, United Kingdom (Dawson, 1953a). 

Remarks. Porphyrostromium ciliare is apparently 

known from only one northern Gulf collection, and its presence 

in the Gulf of California needs to be verified. The relationship of 

Gulf specimens referred to P. ciliare and E. discigera also needs to 

be investigated (see also Remarks under Erythropeltis discigera). 

Sahlingia Kornmann

Sahlingia Kornmann, 1989:227.

Algae are compact, single-layered prostrate discs, composed 

of laterally adjoined, radiating, pseudodichotomously to irregularly branched prostrate filaments. Growth is by oblique divisions of the marginal cells in an alternating sequence. Intercalary 

growth can also occur in the central portions of the disc. Cells 

of the center and outward toward the margins are rectangular to 

FIGURE 15. Species of Porphyrostromium. A, B. Porphyrostromium boryanum: A. Upper portion of thallus. B. Basal portion of 

thallus (A, B after Ardré, 1970: pl. 4: figs. 10, 11). C. Porphyrostromium ciliare: Young thallus showing development of the monostromatic basal disc (after Dawson, 1953a: pl. 1, fig. 2, as Erythrotrichia 

ciliaris). 
NUMBER 96 • 2 5

irregular; bifurcate cells present in the outermost margin. Cells 

have several band-shaped or cup-shaped plastids, circular pyrenoids, and they lack pit plugs. 

Monosporangia are produced by unequal division of vegetative cells within the central part of the disc. The smaller of the 

two resulting cells, separated by an oblique (curving) wall, becomes the monosporangium. Sexual reproduction is unknown.

Remarks. Although it has been suggested that Sahlingia may be congeneric with Erythrocladia, Zuccarello et al. 

(2010) recently provided molecular support for their generic 

separation. In another study, Zuccarello et al. (2011) found 

“Sahlingia-like” discs in culture studies of some Porphyrostromium. The reported Gulf of California species will need to be 

cultured and molecularly tested to verify their taxonomy.

There is one species of Sahlingia in the northern Gulf of 

California.

Sahlingia subintegra (Rosenvinge) Kornmann

FIGURE 10B

Erythrocladia subintegra Rosenvinge, 1909:73, figs. 13, 14; Børgesen, 

1924:268; Kylin, 1925:9, fig. 3C–G; Inagaki, 1935:41; Kylin, 

1937:43, fig. 17D; Kylin, 1941:3; Dawson, 1944a:251; Smith, 

1944:166, pl. 36: fig. 6; Dawson, 1945c:65; Hollenberg, 1948:156; 

Tanaka, 1952:75, figs. 35, 36; Dawson, 1953a:5; 1961b:402; 

1961c:408, pl. 9: fig.2; 1962b:191, 229, fig. 53; Huerta-Múzquiz 

and Tirado-Lizárraga, 1970:127; Huerta-Múzquiz and GarzaBarrientos, 1975:7; Abbott and Hollenberg, 1976:284, fig. 227; 

Schnetter and Bula-Meyer, 1982:109, pl. 11: figs. D, E; PachecoRuíz and Aguilar-Rosas, 1984:71, 76; Mendoza-González and 

Mateo-Cid, 1985:28; Huerta-Múzquiz and Mendoza-González, 

1985:46; Salcedo-Martínez et al., 1988:83; Dreckmann et al., 

1990:27; Mateo-Cid and Mendoza-González, 1991:18; Stewart, 

1991:61; Mendoza-González and Mateo-Cid, 1992:16; ServiereZaragoza et al., 1993a:483; González-González et al., 1996:309, 

fig. 26; Yoshida, 1998:432, fig. 3-1J.

Sahlingia subintegra (Rosenvinge) Kornmann, 1989:227, figs. 1, 6–13; 

L. Aguilar-Rosas et al., 2000:130, 137; Mateo-Cid et al., 2000:63; 

Serviere-Zaragoza et al., 2007:11; Zuccarello et al., 2010:365, figs. 

2b–g, tbls. 1, 2; Fernández-García et al., 2011:64.

Erythropeltis subintegra Kornmann et Sahling, 1985:224, fig. 8; Bula-Meyer, 

1995:32.

Erythrocladia irregularis f. subintegra (Rosenvinge) Garbary, G. I. Hansen et 

Scagel, 1981:154.

Erythrotrichia polymorpha sensu Setchell and Gardner, 1924:741; GonzálezGonzález et al., 1996:200 [non Erythrotrichia polymorpha M. Howe, 

1914:77].

Algae epiphytic, monostromatic and disc shaped, up to 

300 μm in diameter, composed of prostrate, laterally coalesced 

filaments throughout; outermost cells mostly bifucate; margins 

entire, nearly even. Cells isodiametric or longer than wide, 2–5 

μm wide and 5–12 μm long; pyrenoids circular.

Asexual reproduction by monosporangia, up to 15 μm in 

diameter, formed in central part of disc. Sexual reproduction 

unknown.

Habitat. Epiphytic on various algae, including species of Valoniopsis, Cladophora, Chaetomorpha, Dictyota, Polysiphonia, and Griffithsia; intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena; Nayarit to Jalisco. Eastern Pacific: Alaska 

to Baja California; Colima to Oaxaca; Isla Socorro (Islas Revillagigedo); El Salvador; Costa Rica; Isla Gorgona, Colombia; 

Rapa Nui (Easter Island; Isla de Pascua). Western Pacific: Japan; 

Vietnam.

Type Locality. Epiphytic on Polysiphonia urceolata; Møllegrund, off Hirshals, Skagerrak, northern Denmark.

Remarks. Heerebout (1968, as Erythrocladia subintegra) suggested that Sahlingia subintegra and Erythrocladia irregularis were conspecific. Later, E. subintegra was considered to 

be a taxonomic form (forma), as E. irregularis f. subintegra Garbary, G. I. Hansen et Scagel (1980). Since then, culture studies by 

Kornmann (1989) showed differences in development following 

germination and in the morphological characters of monospore 

size and the disc margins, thus separating the two, and recognizing S. subintegra with nearly even margins and E. irregularis

with uneven, irregular margins.

The presence or absence of pyrenoids was noted to be an 

important generic character by Zuccarello et al. (2010). Pyrenoids are not always evident in some Gulf specimens referred to 

S. subintegra, possibly an artifact of preservation. This should 

be carefully studied, particularly in freshly collected specimens, 

as there may be more than one similar looking genus in the Gulf 

of California.

PART II: SUBPHYLUM EURHODOPHYTINA

Eurhodophycidae F. Magne, 1989:112.

Eurhodophytina (F. Magne) G. W. Saunders et Hommersand, 2004:1503.

Ultrastructurally, the Golgi apparatus (Golgi body), an organelle within eukaryotic cells, is found in an endoplasmic reticulum/mitochondrial association. Life histories, where known, 

are biphasic or triphasic. Pit plugs are present between cells in at 

least one stage of sexual life histories. (Diagnostic characters are 

after Saunders and Hommersand, 2004.)

The subphylum Eurhodophytina contains two classes; both 

are well represented in the northern Gulf of California.

KEY TO THE CLASSES OF THE EURHODOPHYTINA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli uniseriate filaments or monostromatic or distromatic blades; cells without pit plugs; female reproductive structures 

comparatively simple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bangiophyceae
2 6 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

1b. Thalli simple to branched filaments, or terete, compressed or flat, unbranched to branched cylindrical, strap-shaped to 

broad blades; structurally simple to complex pseudoparenchymatous anatomy; cells with pit plugs; female reproductive 

structures complex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Florideophyceae

PART IIA. BANGIOPHYCEAE

Bangiophyceae Wettstein, 1901:187

The class Bangiophyceae contains microscopic to macroscopic algae that are of diverse morphologies. They may be (1) 

unicellular; colonial masses of cells; (2) prostrate and disc shaped; 

(3) simple to branched filaments; or (4) narrow to broad foliose blades. Growth is by intercalary cell division (rarely apical). 

Cells are uninucleate, generally with 1 or 2 plastids (variously 

shaped parietal or disc-like plastids have been reported), and 

may be with or without pyrenoids. The cells contain chlorophyll 

a and one or more accessory pigments, including phycoerythrin 

and phycocyanin that occur in discrete submicroscopic units, the 

phycobilisomes. The predominance of one or the other of these 

pigments provides rose-colored (phycoerythrin) or grayish-redcolored (phycocyanin) thalli. 

The reproductive structures of Bangiophycean algae are 

less complicated than those of the Florideophyceae. Asexual reproduction is mostly by monospores, archeospores, or neutral 

spores, produced by direct metamorphosis of a vegetative cell, or 

by divisions of vegetative cells. Sexual reproduction is unknown 

or at least not fully understood in most genera. Where reported, 

sexual reproduction involves simple zygotogsporangia that are 

formed by direct transformation of a vegetative cell. Spermatia 

are also similarly produced by divisions of a vegetative cell. Fertilized zygotosporangia develop zygotospores by divisions within 

the transformed cell. Zygotospores (“carpospores”) of some species, e.g., Porphyra, Pyropia, and Bangia, produce an epizoic or 

endozoic, shell-boring, filamentous “Conchocelis-phase.” 

Remarks. The large class Bangiophyceae with its 

subclass Bangiophycidae Wettstein (1901) contains two orders, 

most of which are marine species but a few species are known 

from freshwater. 

The class is represented by some members of the Bangiales 

in the northern Gulf of California.

Bangiales

Bangiales Nägeli, 1847:136 [as “Bangiaceae” (see Silva et al., 1996a:914)].

Bangiales F. Schmitz in Engler, 1892:15.

Algae are of a variety of morphological forms, discoid, filamentous, tubular, or foliose. In structure members are multicellular and lack a conspicuous gelatinous matrix. Growth is by 

intercalary cell division.

Asexual reproduction is by the formation of monospores, 

archospores, or neutral spores, formed by division of a vegetative cell and development of the resulting smaller cells into spores. 

What is apparently sexual reproduction (but difficult to interpret—

fertilization has not been convincingly demonstrated) occurs in 

most members. The zygotosporangium forms zygotospores by division and redivision of the contents of a vegetative cell. Spermatia are 

also formed by the repeated division of a vegetative cell’s contents.

Remarks. Since some genera of the Bangiales were 

found to be polyphyletic (Müller et al., 2005a), at least 13 new 

or resurrected genera have been recognized (Sutherland et al., 

2011).

A monotypic order, with some members, the Bangiaceae, 

reported in the Gulf of California.

Bangiaceae

Bangiaceae Engler, 1892:16, nom. cons.; Silva, 1980:80 [for name conservation of Bangiaceae, see Silva, 1980:106; 1993b:707]. 

Porphyraceae Kützing, 1843:382 [as “Porphyreae”].

Members of this family are of two morphologies, either 

cylindrical, tubular filaments or flattened and blade-like. The 

foliose members may be monostromatic (one cell layer) or distromatic (two cell layers) throughout. Cells are uninucleate, usually with one or sometimes with two plastids, but at least one has 

multiple plastids. Plastids contain one pyrenoid.

Asexual reproduction is by repeated division of a vegetative cell into two or more smaller cells, each of which becomes 

a monospore. In assumed sexual reproduction, a zygotosporangium is formed by transformation of a vegetative cell, which 

by further divisions produces zygotospores. A short trichogyne 

has been reported in some, but this is in need of reinvestigation 

(Dixon, 1973). Spermatia are also formed by division and redivision within vegetative cells.

Culture studies have shown heteromorphic life histories 

involving macroscopic filaments (e.g., Bangia) or blades (e.g., 

Porphyra, Pyropia) and a microscopic, filamentous Conchocelisphase inhabiting shells or other calcium carbonate substrate 

(Drew, 1949, 1954, 1956a; Kurogi,1953a, 1953b; Tseng and 

Chang, 1954, 1955a, 1955b; Iwasaki,1961; Conway and Cole, 

1977). Additionally, the asexual stage of each of these phases 

may repeatedly reproduce itself asexually depending on environmental conditions, primarily photoperiod and temperature for 

Bangia and Porphyra (see summary in Dixon, 1973).

Remarks. Molecular sequencing and phylogenetic 

analyses have elucidated many new taxa as well as the need for 

reevaluation of generic concepts in the Bangiales (e.g., Nelson 

et al., 2003, 2006; Niwa et al., 2003; Broom et al., 2004). The 

generic separation of two of the genera, Bangia and Porphyra C. 

Agardh (1824), is problematic as studies have revealed them in a 

monophyletic lineage (e.g., Stiller and Waaland, 1993; Oliveira 

et al., 1995; Müller et al., 2001a, 2001b; Milstein and Oliveira, 

2005). Müller et al. (2003, 2005a) noted Bangia as well as Porphyra to be polyphyletic, and recently Sutherland et al. (2011) 
NUMBER 96 • 2 7

provided molecular support for recognization of several genera, 

six of which were found within Porphyra, and there are probably more taxa in Bangia. Despite habit differences, there are 

no clear morphological or anatomical characters that support 

generic separations that are consistent with their phylogenetic 

relationships (Nelson et al., 2005; Zuccarello, 2011).

There are two genera of Bangiaceae currently known in 

the Gulf of California: the economically important genus Pyropia (e.g., Huerta-Múzquiz, 1961; Miyata and Notoya, 1997) 

and the cosmopolitan Bangia. The microscopic Conchocelisphase has as yet remained undetected in the field in the Gulf of 

California.

KEY TO THE GENERA OF BANGIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Thallus filamentous, cylindrical; uniseriate in lower portions and distally 2 or more cells wide; or multiseriate throughout, lower portions 4–6 cells wide, upward 6–20 cells wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bangia

1b. Thallus foliose; flat monostromatic blades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pyropia

Bangia Lyngbye

Bangia Lyngbye, 1819:82.

Algae are erect and may form clumps of a few to many unbranched, cylindrical, purple-black to rusty-colored filaments, 

2.0 mm to 35 cm long. Smaller or immature thalli are attached 

by a dilated basal cell, which in older thalli becomes supplemented by a dense base of filiform rhizoids that grow downward 

from lowermost cells of the filament. Filaments of cells may be 

(1) multiseriate, (2) uniseriate in juvenile thalli and remain so, or 

(3) initially uniseriate and become multiseriate and broader in 

the upper portions of older thalli. Cells have a large plastid with 

a single central pyrenoid.

Life histories, where known, involve an irregularly branched, 

microscopic, filamentous Conchocelis-phase that is developed 

from zygotospores of the Bangia-phase. Cells of Conchocelis-phase 

filaments contain a ribbon-shaped plastid, grow within calcareous 

shells (or other calcium carbonate substrates), and produce conchospores that germinate into the gametophytic Bangia-phase.

Reproductive cells, sporangia, and zygotosporangia or spermatangia, are formed by the differentiation of vegetative cells 

in the upper regions of Bangia filaments. Monosporangia or 

archeospores are produced on sporangial thalli, separate from 

the gametophytic thalli. Zygotosporangia are formed by direct 

transformation of vegetative cells into groups of 8 to 16 zygotosporangia. Spermatangia are formed by repeated division of 

vegetative cells into groups of 32–128 colorless, small spermatia.

Remarks. Bangia species are mostly marine and 

are worldwide in distribution in subtropical to boreal regions. 

Taxonomically, species of Bangia are relatively simple filaments 

and have been separated primarily on filament diameter and 

karyotype. Molecular sequencing and phylogenetic analyses 

have revealed new taxa, for example, new genera Minerva W. A. 

Nelson, Dione W. A. Nelson (both in Nelson et al., 2005), and 

Pseudobangia K. M. Müller et Sheath (in Müller et al., 2005a) 

that closely resemble Bangia. In addition to a resolved Bangia

clade that included Bangia, Clymene W. A. Nelson (in Sutherland et al., 2011), and Porphyra, nine other marine filamentous 

species of “Bangia” remain unresolved and may involve one or 

more genera (Sutherland et al., 2011). Similar methodologies applied to Gulf of California Bangia species are needed to elucidate 

their taxonomic status and phylogenetic relationships to other 

Bangiales. 

Two species of Bangia are recorded in the northern Gulf of 

California, one known from Pacific Mexico and the other tentatively referred to a California species.

KEY TO THE SPECIES OF BANGIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Filaments multiseriate throughout; 4–6 cells broad in lower portion, up to 20 cells wide in upper portion; simple 

(unbranched) or with short, spur-like branches basally . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. enteromorphoides

1b. Filaments uniseriate in basal portion, becoming multiseriate in upper portions; unbranched throughout . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. vermicularis?

Bangia enteromorphoides E. Y. Dawson

FIGURE 16

Bangia enteromorphoides E. Y. Dawson, 1953a:13, pl. 1: fig. 8; 1961b:402; 

González-González, 1993:441; González-González et al., 1996:175, 

384.

Algae of several minute, cylindrical to broadening filaments, 

up to 2 mm long, with broadly rounded apices; attached by a 

mass of rhizoids, epiphytic or partially endophytic on surface 

cells of host algae. Filaments about 20 μm in diameter, multiseriate at base, of 4 transverse rows of cells; usually unbranched 

or with a few spur-like branchlets in lower portion. Lowermost 

portions of filaments in rows of 4(–6) cells producing attachment 

rhizoids; upward with rows of 4–6 cells; upper portion becoming 

broader, up to 150 μm wide; cells squarish to more or less angular, in transverse rows of up to 20 cells. Thalli initially solid, but 

can become hollow above in larger specimens.

Asexual reproduction unknown. Spermatangia in groups 

of 16–32 with some apparently nonreproductive cells among 

them in fertile area of upper region of filaments. Carpogonia 

not known.
2 8 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Habitat. Entangled with Asparagopsis and epiphytic 

on Gelidium; low intertidal to shallow subtidal, down to at least 

5 m depths. 

Distribution. Gulf of California: Punta La Gringa, 

Bahía de Los Ángeles; Mazatlán, Sinaloa to Jalisco. Eastern Pacific: Oaxaca.

Type Locality. Epiphytic on Gelidium sclerophyllum; north of El Faro de Olas Atlas, Mazatlán, Sinaloa, Gulf of 

California, Mexico. 

Remarks. Apparently little known or overlooked, 

Bangia enteromorphoides was described from the southern 

Gulf of California (Dawson, 1953a). A single small specimen 

(JN-3030b, US Alg. Coll. microscope slide 8696) from Punta La 

Gringa, probably a juvenile, shows the characteristic 4-celled 

row across the basal region and is tentatively referred to B. enteromorphoides. It is included in hopes that the species will again 

be collected and its generic and specific status will be further 

investigated.

Bangia vermicularis? Harvey

FIGURE 17

Bangia vermicularis Harvey, 1858:55, pl. 49: figs. A1–10; Kylin, 1941:4; 

Smith, 1944:167, pl. 37: figs. 4–6; Dawson, 1961b:402; Sheath and 

Cole, 1984:383; Scagel et al., 1986:128; Stewart, 1991:63; R. AguilarRosas and Aguilar-Rosas, 1994:519; Pacheco-Ruíz et al., 2008:205; 

Lynch et al., 2008:609, figs. 7, 8.

Bangia fuscopurpurea [only Gulf of California and Pacific Mexico material] sensu Tanaka, 1950:165, fig. 3; 1952:23, pl. 2: fig. 2; Dawson, 

1953a:13; 1961b:402; 1962b:210, 229, fig. 108; Abbott and Hollenberg, 1976:294, fig. 237; Silva, 1979:315; Pacheco-Ruíz and 

Aguilar-Rosas, 1984:71,76; Huerta-Múzquiz and Mendoza-González, 

1985:48; González-González et al., 1996:302 [non Bangia fuscopurpurea (Dillwyn) Lyngbye, 1819:83].

Bangia atropurpurea sensu Mateo-Cid and Mendoza-González, 1994b:38; 

Mendoza-González et al., 1994:105; Hoffman and Santelices, 

1997:206, fig. 52(1–5); Abbott, 1999:47, fig. 2A–E; Mateo-Cid et 

al., 2000:63 [non Bangia atropurpurea (Roth) C. Agardh, 1824:76; 

basionym: Conferva atropurpurea Mertens ex Roth, 1806:208; =Bangiadulcis atropurpurea (Roth) W. A. Nelson, 2007:885 (note that the 

taxonomic status of Bangiadulcis is uncertain; see Silva and Nelson, 

2008:1352; Wynne and Schneider, 2010)].

Algae of several, often entangled filaments, dark red to 

purple-black, sometimes rusty brown, up to 3 cm long; usually growing in small to extensive patches. Filaments more or 

less cylindrical and unbranched; uniseriate at base and initially 

attached by a basal cell; later becoming attached by rhizoids 

descending from lowermost cells. Filaments mostly 40–60 μm 

in diameter, with cells usually wider than long. Uniseriate filaments become multiseriate in upper portions; filaments may be 

slightly constricted; cells may be as long as or longer than wide, 

sometimes arranged in more or less transverse rows. Cells about 

(4–)6–12 μm tall and (8.0–)10–15 μm in diameter; in upper portions, cells (12–)14–20 μm tall and 15–20 μm in diameter.

Asexual reproduction unknown in Gulf material. Carpogonium formed by transformation of vegetative cell. Spermatia 3–4 

μm in diameter, formed by repeated divisions of vegetative cells.

Habitat. On rocks; high to upper mid intertidal.

Distribution. Gulf of California: Isla Partida; La 

Paz to Punta Arena; Mazatlán. Eastern Pacific: Alaska to Costa 

Rica; Chile. Western Pacific: Japan. 

Type Locality. “Golden Gate” entrance to San 

Francisco Bay (Harvey, 1858) (probably below what is now the 

Golden Gate Bridge at Fort Point or the San Francisco Presidio 

[Silva, 1979]), San Francisco, San Francisco County, northern 

California, USA. 

Remarks. There is a long history of taxonomic and 

nomenclatural debate over species limits and the number of species included in Bangia. Although often considered to be a single 

morphologically variable species, as “B. fuscopurpurea,” with 

a worldwide distribution, others have recognized that there are 

distinct taxa among populations of Bangia. Initially, Müller et al. 

(2003, as “B. fuscopurpurea”) concluded that the marine Bangia

from the Pacific and Atlantic coasts of North America should be 

FIGURE 16. Bangia enteromorphoides: Rhizoids descending from 

the lower 4 basal cells; upward the axis is 4 cells across (entangled 

with JN-3030b, US Alg. Coll. microscope slide 8696). 
NUMBER 96 • 2 9

referred to as a single entity until their phylogenetic relationships 

can be resolved (see also Müller et al., 1998) and later pointed 

out that Bangia as well as Porphyra are polyphyletic (Müller et 

al., 2005a). Müller et al. (2003) provided evidence that there are 

several distinct clades of specimens identified as “B. fuscopurpurea (Dillwyn) Lyngbye (1819),” and more recently, Sutherland 

et al. (2011) concluded that the genus to which the marine “Bangia fuscopurpurea” belongs remains unknown.

Earlier cytological studies by Cole et al. (1983) and Sheath 

and Cole (1984) indicated that there are two geographically separate, but similar looking, species (Smith, 1944) on the basis of 

their chromosome numbers (n): the northeastern Pacific Bangia

vermicularis (n = 3) and the Atlantic “B. atropurpurea” (n = 

4). However, Bangia atropurpurea (Roth) C. Agardh (1824) was 

subsequently shown to belong to a new freshwater genus (Müller 

et al., 2003) as Bangiadulcis atropurpurea (Roth) W. A. Nelson 

(2007); yet the taxonomic status of Bangiadulcis has been questioned by Silva and Nelson (2008). 

All Gulf of California and Pacific Mexico material identified as “B. fuscopurpurea” needs to be reexamined. For now the 

Gulf of California material is tentatively referred to the Pacific 

Coast species, Bangia vermicularis. Although B. vermicularis 

and another northern California species, B. maxima N. L. Gardner (1927a), have been treated as synonyms included within “B. 

fuscopurpurea” by Abbott and Hollenberg (1976), Lynch et al. 

(2008: figs. 7, 8) noted that despite their morphological similarities, B. vermicularis and B. maxima were not particularly close 

phylogenetic relatives. 

Dawson (1953a, as “B. fuscopurpurea”) stated the Isla Partida specimens were a morphological variant in which cells in the 

lower portions of their filaments were longer than wide and less 

than 8 μm in diameter. These dimensions are much smaller than 

those of specimens from the Pacific coast of California, where B. 

vermicularis is typically characterized to have much wider and 

shorter cells in the lower portion that are about half as long as 

broad, 10–15 μm in diameter and about 5–12 μm long (Abbott 

and Hollenberg, 1976). The relationship of Gulf of California 

specimens, herein referred to B. vermicularis with a query, to 

the other species of Bangia and “Bangia-like” taxa needs further 

morphological and molecular evidence to elucidate their taxonomic status and relationships.

Pyropia J. Agardh

Pyropia J. Agardh, 1899:149, fig. 5a–d; Sutherland et al., 2011:1142.

Gametophytes are foliose, monostromatic, and of various 

shapes, including linear, lanceolate, ovate, orbicular or funnellike, and mostly entire or sometime divided. Blades arise from 

a small discoid holdfast composed of rhizoidal cells produced 

from the basal cells. Color is variable between, and in some cases 

within, species and may be rose to dark red, purple, or green or 

combinations of these colors. Species range in size from a few 

centimeters to some that can be several meters in length, with 

blade margins that can be smooth, dentate, planar, undulate, or 

ruffled. Cells in most of the species have a single plastid, although 

some may have cells with two plastids. Pit plugs are absent. 

Archeospores or neutral spores are known to be produced 

by the blades of a few of the species (Nelson and Knight, 1996; 

Nelson et al., 1999). The reproductive portions of the macroscopic gametophytes are either (1) monoecious with zygotosporangia (sensu Guiry, 1990b) or spermatangia produced by 

groups of cells; (2) monoecious and divided into zygotosporangial and spermatangial groups separated by a vertical or horizontal line; (3) monoecious with zygotosporangia or spermatangia 

intermixed in fertile portions of the blade; or (4) dioecious. Two 

of these groups develop continuous reproductive areas along 

the blade margins: zygotosporangia and spermatangia in species 

that are monoecious and sectored; and, zygotosporangia or spermatangia in dioecious species (after Sutherland et al., 2011). 

The sporophytic, filamentous “Conchocelis-phase” is 

known in the life histories of some of the species. In nature, its 

branched, uniseriate filaments grow on and/or penetrate and 

grow in calcareous substrata such as shells, coral rubble, or crustose coralline algae. Cells of the “Conchocelis-phase” have parietal band-shaped to stellate plastids and pit plugs between the 

cells. Asexual reproduction, where known, is by conchospores 

FIGURE 17. Bangia vermicularis?: A. Basal portion. B. Middle portion. C. Upper portions of thallus (A–C, after G. M. Smith, 1944: pl. 

37, figs. 4–6).
3 0 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

or monospores produced by the filamentous sporophyte (e.g., 

Kapraun and Luster, 1980, as Porphyra rosengurtii J. Coll et 

J. Cox, 1977; which is now Pyropia elongata (Kylin) Neefus et 

J. Brodie in Sutherland et al., 2011).

Remarks. The foliose gametophytes of Pyropia

grow on hard substrata (such as rocks) or may be epiphytic or 

epizoic. Some species are short-lived (ephemeral) and seasonal, 

others live longer, through two or more seasons. Most of them 

are found in subtropical, temperate, or sub-boreal waters.

Pioneering culture studies by Drew (1949, 1956a) of Porphyra umbilicalis Kützing (1843), and by Kurogi (1953a, 1953b) 

and Tseng and Chang (1954, 1955a, 1955b) on Porphyra tenera Kjellman (1897; which is now Pyropia tenera (Kjellman) 

N. Kikuchi et M. Miyata in Sutherland et al., 2011) revealed 

heteromorphic life histories involving the foliose-phase and the 

filamentous Conchocelis-phase (see also Iwasaki, 1961; Conway and Cole, 1977). Porphyra was found to have the most 

primitive plastid genome known (Reith and Munholland, 1995; 

Reith, 1995). Molecular studies of some species of Porphyra revealed the genus to contain a polyphyletic assemblage of taxa 

that, although divergent at the molecular level, have converged 

on simple blade morphologies (e.g., Nelson et al., 2003, 2006). 

Sutherland et al. (2011) provided molecular phylogenetic evidence that the genus Porphyra should be based on Porphyra purpurea (Roth) C. Agardh (1824; basionym: Ulva purpurea Roth, 

1797; e.g., Liu et al., 1994; Irvine and Brodie, 1997; Lindstrom 

and Fredericq, 2003, as Porphyra rediviva Stiller et Waaland, 

1996; Bray et al., 2007) and restricted Porphyra to five species. 

The rest of the previously known species of “Porphyra” belong 

in six different genera: Boreophyllum S. C. Lindstrom, N. Kikuchi, M. Miyata et Neefus (in Sutherland et al., 2011), Fuscifolium S. C. Lindstrom (in Sutherland et al., 2011), Lysithea W. A. 

Nelson (in Sutherland et al., 2011), Miuraea N. Kikuchi, S. Arai, 

G. Yoshida, J. A. Shin et M. Miyata (in Sutherland et al., 2011), 

Pyropia J. Agardh (1899), and Wildemania De Toni (1890). 

There are more than 75 species previously in Porphyra that belong in Pyropia, a genus based on Pyropia californica J. Agardh 

(1899; which is now Pyropia nereocyctis (C. L. Anderson) S. C. 

Lindstrom in Sutherland et al., 2011; basionym: Porphyra nereocystis C. L. Anderson in Blankinship and Keeler, 1892; Porphyra 

nereocystis C. L. Anderson 1891, nom. nud.). Sutherland et al. 

(2011) noted there are another eight probable genera that are to 

be resolved in later studies. 

Many species of Pyropia, including those of the Gulf of 

California—until recently called Porphyra (Sutherland et al., 

2011; Zuccarello, 2011)—have a long history as food. It was 

eaten as early as ad 668 in coastal regions of the Korean peninsula and at least since ad 701 in Japan, where around ad

987 it was referred to as a common food (Miyata and Notoya, 

1997). Korean texts mention cultivation of “Porphyra” as early 

as 1420, and it was probably introduced to China in 1429. It 

has been a traditional food since antiquity, with cultural and 

nutritional importance to indigenous people of the northeastern 

Pacific Coast (Turner, 2003).

The species of Porphyra and Pyropia may be the single most 

important seaweed food in the world. Since the 1950s the biology of “Porphyra” has been extensively studied because of its 

economic value to the mariculture industry in the production of 

nori or amanori (Japan and China), gim (Korea), or purple laver 

(England and Ireland) (e.g., Mumford and Miura, 1989; Miyata 

and Notoya, 1997; Yoshida, 1997). Today the major producers of nori are Japan, Korea, and China, with an annual market 

value of over US$2 billion. Although Gulf of California species 

may have economic potential, they are not currently being commercially grown or harvested (e.g., Zertuche-González, 1994). A 

species of Pyropia, or possibly Porphyra, from Baja California 

was noted by Huerta-Múzquiz (1961, as “Porphyra perforata 

var. segregata”) to be of economic interest.

One species of foliose Pyropia has been reported in the 

southern Gulf from La Paz (Huerta-Múzquiz and MendozaGonzález, 1985): Pyropia perforata (J. Agardh) S. C. Lindstrom 

in Sutherland et al. (2011), a California species recorded from 

Alaska to Pacific Baja California Sur (Dawson, 1953a; Abbott 

and Hollenberg, 1976; Huerta-Múzquiz, 1978; Pacheco-Ruíz 

and Aguilar-Rosas, 1984; Scagel et al., 1989; Mateo-Cid and 

Mendoza-González, 1994b:38; Pacheco-Ruíz et al., 2005b; all 

as Porphyra perforata J. Agardh, 1883). In addition to Pyropia perforata there are five other species also recorded from the 

Pacific coast of Mexico (R. Aguilar-Rosas et al., 2007b): Pyropia gardneri (G. M. Smith et Hollenberg) S. C. Lindstrom, 

P. lanceolata (Setchell et Hus) S. C. Lindstrom, P. suborbiculata 

(Kjellman) J. E. Sutherland, H. G. Choi, M. S. Hwang et W. A. 

Nelson, and P. thuretii (Setchell et E. Y. Dawson) J. E. Sutherland, L. E. Aguilar-Rosas et R. Aguilar-Rosas (all four new combinations in Sutherland et al. , 2011), and the newly described 

P. raulaguilarii Mateo-Cid, Mendoza-González et Sentíes (in 

Mateo-Cid et al., 2012).

Three species of Pyropia are present in the northern Gulf of 

California. All are monostromatic species, and two of them are 

endemic.

KEY TO THE SPECIES OF PYROPIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Blades monoecious; broadly reniform to lanceolate; rose to purplish. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. thuretii

1b. Blades dioecious; linear to ligulate or oval to sometimes broader than tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Blades long, linear to ligulate, comparatively narrow, 0.3–1.2 cm wide; pale to bright rose; zygotosporangia in packets of 

8; spermatia in packets of 128 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. pendula

2b. Blades mostly wider, generally more than 2.0 cm, up to 4.0 cm in width; lanceolate to broadly oval; entire or divided; pale 

rose to greenish or purplish red; zygotosporangia in packets of 8; spermatia in packets of 64 . . . . . . . . . . P. hollenbergii
NUMBER 96 • 3 1

Pyropia hollenbergii (E. Y. Dawson) J. E. Sutherland, 

L. E. Aguilar-Rosas et R. Aguilar-Rosas

Porphyra hollenbergii E. Y. Dawson, 1953a:14, pl. 13: fig. 1; 1959a:19; 

1961b:402; González-González et al., 1996:257; Yoshida et al., 1997:8, 

fig. 3; Mateo-Cid et al., 2000:63; R. Aguilar-Rosas et al., 2007b:351, 

figs. 1–10; López-Vivas et al., 2011:520.

Pyropia hollenbergii (E. Y. Dawson) J. E. Sutherland, L. E. Aguilar-Rosas et 

R. Aguilar-Rosas in Sutherland et al., 2011:1143.

Porphyra perforata f. segregata sensu Dawson, 1944a:253 [non Porphyra 

perforata f. segregata Setchell et Hus in Hus, 1900:64, which is now 

Porphyra segregata (Setchell et Hus) V. Krishnamurthy, 1972:44].

Algae one to several, monostromatic blades, lanceolate or 

linear to ovate, sometimes obovate in lower portions with lanceolate upper portions, or broadening upward, often more or less 

divided (lacerated); 6–16(–22) cm long by 1.0–7.5 cm wide and 

45–60 μm thick; pale rose to greenish rose or purplish red; attached by rhizoids from basal cells, 25–40 μm long and 18–28 

μm wide, forming a discoid holdfast. Cells in surface view, with a 

thick cell wall, 12–20 μm in length, 8–12 μm wide; in transection, 

cells slightly elongated, 10–23(–30) μm tall and 8–20 μm wide.

Asexual reproduction unknown. Gametophytes dioecious. 

Zygotosporangia (“carposporangia”) in packets of 8 zygotospores, darker red than vegetative cells; forming continuous 

darker “reddish” patches along blade margins. Spermatangia on 

separate thalli; in packets of 64 spermatia; forming continuous 

whitish-yellowish margins on both sides of blade.

Habitat. On intertidal rocks; mostly high to mid 

intertidal.

Distribution. Gulf of California: Bahía Bocochibampo (west-northwest of Guaymas); Isla San Ildefonso to Bahía 

Agua Verde; Punta Arena (north of Cabo Pulmo).

Type Locality. On upper intertidal rocks; Bahía 

Agua Verde, Baja California Sur, Gulf of California, Mexico.

Remarks. Pyropia hollenbergii is apparently an endemic species, generally found from winter to spring. It primarily 

differs from other similar monostromatic, dioecious species of Pyropia by the number of packets of spermatia and its usually divided 

thallus with ruffled margins and purplish to rose to slightly greenish 

color (Dawson, 1953a). The life history phases of the Gulf P. hollenbergii, the foliose gametophytes and filamentous Conchocelisphase, were found to be controlled by a combination of photoperiod 

and high water temperatures (López-Vivas et al., 2011).

The isotype of Pyropia hollenbergii shows variability in 

shape, from more or less lanceolate to broader, oval forms (Porphyra hollenbergii: EYD-539-40, US Alg. Coll.-56865). The 

broader forms of Pyropia hollenbergii can be somewhat similar 

to Gulf Pyropia thuretii but differ primarily in being dioecious, 

whereas P. thuretii is monoecious.

Pyropia pendula (E. Y. Dawson) J. E. Sutherland, L. E. AguilarRosas et R. Aguilar-Rosas

FIGURE 18B

Porphyra pendula E. Y. Dawson, 1953a:16, pl. 13: fig. 2; 1961b:402; 

Espinoza-Avalos, 1993:333; González-González et al., 1996:258; 

Yoshida et al., 1997:11, fig. 3; López-Vivas and Riosmena-Rodríguez, 

2000:45; L. Aguilar-Rosas et al., 2004:121, figs. 2a–c, 3–10; Nelson et 

al., 2006:250, 253, 254; Pacheco-Ruíz et al., 2008:205.

Pyropia pendula (E. Y. Dawson) J. E. Sutherland, L. E. Aguilar-Rosas et R. 

Aguilar-Rosas in Sutherland et al., 2011:1144.

Algae of monostromatic blades, pale to bright rose, attached 

by a very small discoid holdfast. Blades usually simple, sometimes 

divided near base, linear-ligulate and pendent, to 25 cm long, 

3–12 mm wide; gradually becoming acuminate to apices, 45–50 

μm thick; with ruffled margins. Cells irregularly shaped, to 11 μm 

in diameter in surface view; usually to 25 μm tall in transection.

Asexual reproduction unknown. Zygotosporangia (“carposporangia”) with packets of 8 zygotospores (“carpospores”) 

borne continuously along bright rose red margins and apices of 

blade. Spermatangia with packets of 128 spermatia; borne continuously along yellowish margins and apices of blade.

Habitat. On rocks; upper spray zone, and high to 

mid intertidal.

Distribution. Gulf of California: Isla Patos (off 

north end of Isla Tiburón) to Isla Partida Norte; Isla San Pedro 

Nolasco; Isla Carmén to Isla Espíritu Santo; Calerita to Punta 

Coyote (vicinity of Bahía de La Paz).

Type Locality. On shaded cliff rocks, upper intertidal spray zone; Isla Partida Norte (Isla Cordonazo), western 

island of Islas de la Cintura, Gulf of California, Mexico.

Remarks. Pyropia pendula is an endemic species of 

the Gulf of California, recognized in the field by its linear to lanceolate, often twisting, blades.

Pyropia thuretii (Setchell et E. Y. Dawson) J. E. Sutherland, 

L. E. Aguilar-Rosas et R. Aguilar-Rosas

FIGURE 18A,C,D

Porphyra thuretii Setchell et E. Y. Dawson in Smith, 1944 [May]:171, pl. 

40: fig. 2; Setchell et E. Y. Dawson in Dawson, 1944a[July]:253; Doty, 

1947:161; Dawson, 1953a:18; 1961b:403; Dawson et al., 1964:32, pl. 

28; Norris, 1973:8 [with query]; Abbott and Hollenberg, 1976:302, 

fig. 246; Acleto O. and Endo, 1977:13, figs. 23–29; Garbary et al., 

1981:185; Hawkes, 1982:98, figs. 7–11; Scagel et al., 1989:242; RochaRamírez and Siqueiros-Beltrones, 1991:26, 32; Ramírez and Santelices, 

1991:170; Lindstrom and Cole, 1992: 2069, tbls. 1–3; GonzálezGonzález et al., 1996:258; Yoshida et al., 1997:13, fig. 1; L. AguilarRosas et al., 2000:130, 137; CONANP, 2002:136; L. Aguilar-Rosas 

and Aguilar-Rosas, 2003:159, figs. 2a–c, 3–10; Pacheco-Ruíz et al., 

2008:205; Fernández-García et al., 2011:64.

Pyropia thuretii (Setchell et E. Y. Dawson) J. E. Sutherland, L. E. AguilarRosas et R. Aguilar-Rosas in Sutherland et al., 2011:1145.

Porphyra leucosticta sensu Hus, 1902:199, pl. 20: figs. 1a–3b; Howe, 

1911:499; González-González et al., 1996:258 [non Porphyra leucosticta Thuret in Le Jolis, 1863b:100; which is now Pyropia leucosticta 

(Thuret) Neefus et J. Brodie in Sutherland et al., 2011:1144]. 

Porphyra naiadum sensu Taylor, 1945:133 [in part; only Costa Rica specimens; non Porphyra naiadum C. L. Anderson in Blankinship and Keeler, 1892:148, which is now Smithora naiadum (C. L. Anderson) Hollenberg, 1959:3].
3 2 • SMITHSONIAN CONTRIBUTIONS TO BOTANY
NUMBER 96 • 3 3

Algae a single monostromatic blade, rose to purple, up to 

6(–75) cm tall, attached by rhizoids from basal cells. Blades of 

Gulf specimens oval to broadly reniform, sometimes taller than 

broad, 25–40 μm thick, markedly cordate at base, with a short 

stipe. Cells in transection, subcubical to rectangular, 8–20 μm 

long by 4–10 μm wide; in surface view, polygonal, 10–15 μm 

long by 4–8 μm wide; with a single stellate plastid.

Asexual reproduction unknown. Gametophytes monoecious. 

Zygotosporangia in marginal bands with spermatangia lying in 

alternate streaks diagonal to blade margin. Zygotosporangia with 

zygotospores in packets of 8. Spermatia in packets of 64.

Habitat. On rocks or occasionally epiphytic; high 

intertidal to shallow subtidal, down to 5 m depths.

Distribution. Gulf of California: Rocas Consag; 

San Felipe to Bahía San Luís Gonzága; Puerto Refugio, Isla Ángel 

de la Guarda; Isla Patos (off north end of Isla Tiburón); Isla Partida; Ensenada Bocochibampo; Isla Carmen to Bahía de La Paz; 

Playa Pinitos to Playa Olas Altas (vicinity of Mazatlán), Sinaloa. 

Eastern Pacific: northern British Columbia to central California; 

Todos Santos (Baja California Sur); Costa Rica; Peru.

Type Locality. On Gracilariopsis andersonii

(as “G. sjoestedtii”); Pacific Grove, Monterey County, central California, USA (Dawson, 1944a; Smith, 1944); “floating 

in Carmel Bay, Monterey County, California” (UC-791973; 

Krishnamurthy, 1972:45).

Conchocelis-Phase of Pyropia

FIGURE 19

Conchocelis Batters, 1892:27, pl. 8; Drew, 1949:748; 1954:183; Tseng and 

Chang, 1954:287; 1955a:27; 1955b:375, pls. 1–7; Drew, 1955:373; 

1956a:573; Hollenberg, 1958b:653, figs. 1–13; Hollenberg and Abbott, 1966:38; Richardson and Dixon, 1968:496.

Microscopic filamentous algae; growing on and perforating 

into calcareous substratum (such as old mollusk shells); forming pinkish patches. Uniseriate filaments (1.5–)4–6(–8) μm in 

diameter, highly variable, straight, curving, clavate, or irregular; branching opposite, alternate, or irregular; lateral branches 

sparse to dense; sometimes interwoven, forming a network. Portions of filaments notably swollen, 20–30 μm in diameter, of 

2–10 cells (7.0–75 μm long) irregular-shaped, septate, simple to 

divided inflations. Cells more or less cylindrical, becoming tortuous to irregular, constricted at septae; pit plugs between cells; 

with a single parietal, band-shaped to stellate plastid.

Asexual reproduction by two known modes: (1) conchospores developed from conchosporangia, 13–15 μm in diameter, 

formed in inflated cells of the filaments, and usually superficial 

on calcareous shells; or (2) by protoplasts from a protothallus.

Habitat. Within old mollusk shells, particularly bivalves, and other calcareous substratum; intertidal to subtidal.

Distribution. Gulf of California: Conchocelisphase not yet found in field collections.

Generitype. Conchocelis rosea Batters, 1892:27, pl. 8. 

Type Locality. In empty shells of Mya truncata

Linnaeus (truncate soft-shell clam) and Solen vagina Linnaeus 

(European razor clam); “dredged in 6–8 fathoms off Tan buoy, 

between the islands of Great Cumbrae and Little Cumbrae” 

(Batters, 1892:25), Millport, Firth of Clyde, western Scotland, 

United Kingdom.

Remarks. In culture studies Drew (1949, 1954) and 

Kurogi (1953a, 1953b) observed spores from Porphyra developed into shell-penetrating Conchocelis-like filaments. Since 

then, the “shellboring” Conchocelis-phases or Conchocelis-like 

algae have been reported in the life histories of many other species 

of Bangia, Porphyra, and Pyropia. The Conchocelis-phases have 

been occasionally reported in nature, but because of their similar 

morphologies they are not easily distinguished, making it nearly 

impossible to associate it with the macro-phase of known species. 

FIGURE 18. (Opposite) Species of Pyropia. A. Pyropia thuretii: Habit (EYD-12546, US Alg. Coll.-41997). B. Pyropia pendula: Habit (JN5194a, US Alg. Coll.-160625). C. Pyropia thuretii: Habit, note reproductive regions with irregular streaks along blade margins (JN-5194b, US 

Alg. Coll.-160627). D. Pyropia thuretii: Surface view of cell arrangement within marginal reproductive area showing packets of darker zygotosporangia (JN-5194b, US Alg. Coll. microscope slide 4297). 

FIGURE 19. Conchocelis-phase: Habit of growing filaments developed from zygotospores of Pyropia perforata (after Hollenberg, 

1958b: figs. 3, 9).
3 4 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Molecular studies are needed to test their genetic relationships 

and whether the Conchocelis-phase is unique to certain genera 

or possibly species-specific. Culture studies on Gulf of California 

species of Pyropia and Bangia should reveal whether the expected 

Conchocelis-phases are involved in their life histories, as has been 

found in Gulf P. hollenbergii (López-Vivas et al., 2011).

PART IIB. FLORIDEOPHYCEAE

Florideophyceae Cronquist, 1960:438. 

Florideophyceae Warming, 1884:43 [as “Florideae”]. 

Nemaliophyceae M. Shameel, 2001:245.

The class Florideophyceae is exemplified by an enormous 

diversity of forms; all are essentially filamentous and pseudoparenchymatous in structure. Thalli are formed by the aggregation 

of filaments, which are produced almost exclusively by the division of apical cells (Dixon, 1973); that is, growth is by apical 

cells that together with lateral initials form branched filaments in 

which the cells are linked throughout by pit connections. Intercalary cell division is also known, for example, in some species 

of the Delesseriaceae and Corallinaceae. 

Algae are cylindrical to foliose and branched or unbranched. 

Two main types of construction are found: uniaxial (with a single axial filament) and multiaxial (with several to many axial 

filaments). Most thalli have erect and prostrate portions and are 

heterotrichous in organization. However, this is not found in the 

Ceramiales or in certain of the presumed parasitic genera. Cells 

are uninucleate or multinucleate and generally have several discshaped plastids.

Asexual reproduction is by monospores, bispores, tetraspores, or polyspores produced within sporangia that are borne 

lateral or terminal. Life histories, where known, are usually 

triphasic with gametophytes, carposporophytes, and tetrasporophytes. Most have a tetrasporophyte that develops tetrasporangia, producing four spores. The female gametophyte 

develops carpogonia, each with a trichogyne that is borne lateral or terminal on the carpogonial filaments (“branches”). Fertilization is initiated when spermatia attach to the trichogyne 

of a carpogonium, and the carposporophyte either develops 

directly from the carpogonium or from its derivatives. After 

fertilization, one to numerous special filaments called gonimoblasts are produced. Either all of the cells or only certain cells of 

the gonimoblast develop into carposporangia. Each carposporangium produces a single carpospore or, more rarely, a tetrad 

of carpospores. The female reproductive system is borne singularly or adjacent to others in sori, nemathecia, or conceptacles. 

Cystocarps are either naked or surrounded by involucral filaments or a pericarp. They are borne on the thallus surface or 

embedded within the cortical layers or in some species within 

the medulla. Spermatia are produced within spermatangia 

borne laterally or terminally in clusters, sori, or conceptacles or 

on spermatangial filaments.

Remarks. The largest class of red algae is commonly referred to as the “Florideophyceae,” a descriptive name. 

However, the correct typified name, although little used, is the 

Nemaliophyceae M. Shameel (2001), an elevation in rank of Nemaliophycidae T. A. Christensen (1978; see Silva in Silva et al., 

1996a:911).

The majority of the class Florideophyceae, as in the Bangiophyceae, are marine species, occurring throughout the world’s 

oceans from both poles to the equator. The Florideophyceae 

presently includes five subclasses that are well represented in 

the northern Gulf of California marine flora. The subclasses are 

currently divided into 28 orders, 19 of which are found in the 

northern Gulf.

KEY TO THE SUBCLASSES OF FLORIDEOPHYCEAE IN THE NORTHERN GULF OF CALIFORNIA

(AFTER SAUNDERS AND HOMMERSAND, 2004)

1a. Noncalcified crusts; zonate tetrasporangia; sexual reproduction unknown; pit plugs with single cap membrane but lack 

an outer cap layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hildenbrandiophycidae

1b. Erect or crustose, calcified or noncalcified; ultrastructurally, pit plugs with or without cap layers . . . . . . . . . . . . . . . . 2

2a. Pit plugs with cap layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2b. Pit plugs without cap layers and mostly without cap membranes (at least 1 member without cap layers and with cap 

membranes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3a. Members noncalcified or some calcified (aragonite); ultrastructurally, pit plugs with 2 cap layers; tetrasporangia cruciately divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nemaliophycidae

3b. Calcified (calcite) articulated and crustose corallines; pit plugs with 2 cap layers and the outer pit plug is dome shaped; 

tetrasporangia zonately divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Corallinophycidae

4a. Carposporangia terminal and sessile; carposporophyte developing outward; pit plugs without cap layers and 

membranes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ahnfeltiophycidae

4b. Triphasic life histories; carposporophyte developing directly from carpogonium or carpogonial fusion cell or indirectly 

from auxiliary cell (which received postfertilization diploid nucleus); pit plugs with membranes (with the exception of 

Gelidiales, which has a single cap layer) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rhodymeniophycidae
NUMBER 96 • 3 5

HILDENBRANDIOPHYCIDAE

Hildenbrandiophycidae G. W. Saunders et Hommersand, 2004:1504; 

Schneider and Wynne, 2007:201.

Algae are uncalcified crusts with upper surfaces that are 

usually smooth to slightly irregular or tuberculate, although a 

few have erect branches. Internally, the members are composed 

of a basal layer of laterally adhering, branched filaments and 

upper layers of laterally adhering, simple or branched, erect filaments. Ultrastructurally, the cells have pit plugs with a single cap 

layer and membrane.

Tetrasporangia are zonately or irregularly divided, are apomeiotic, and are borne within sunken, ostiolate conceptacles. 

Gametangial structures are unknown.

Remarks. The subclass Hildenbrandiophycidae has 

the characteristics of the Hildenbrandiales, an order that is represented in the northern Gulf of California. 

Hildenbrandiales

Hildenbrandiales Pueschel et K. M. Cole, 1982:718; Pueschel, 1982:333.

Algae are entirely prostrate and encrusting or may have 

erect axes that arise from a crustose base. Thalli usually spread 

as they grow and can often cover extensive areas. Structurally, 

these crusts are thin and composed of strongly united filaments 

of rows of cells. Their lower surface is closely attached to the 

substratum without rhizoids. Ultrastructurally, the pit plugs have 

a single cap membrane but lack an outer cap layer. 

Tetrasporangia are produced within characteristic sunken 

conceptacles. Tetrasporangia are elongated and zonately or irregularly divided. Sexual reproduction is unknown. 

Remarks. Ultrastructural studies have shown singlelayered pit plugs in Hildenbrandia (Pueschel and Cole, 1982; 

Pueschel, 1982, 1988b, 1989). This character and the presence 

of conceptacles that enlarge in a distinctive manner (i.e., by the 

continuous development of tetrasporangia, which are produced 

by the continuous conversion of vegetative cells that line the conceptacle wall and floor) make this order, with its single family, 

unique among the red algae. Culture studies of tetraspores have 

thus far yielded only sporophytes (Umezaki, 1969; DeCew and 

West, 1977a; Fletcher, 1983), and tetrasporangia remain the only 

reproductive structure known in the order. 

The single family of the order, Hildenbrandiaceae, is represented in the northern Gulf of California.

Hildenbrandiaceae

Hildenbrandiaceae Rabenhorst, 1868:408 [as “Hildenbrandtiaceae”].

Algae are prostrate and entirely crustose or with simple or 

branched axes arising from the crustose base. The lower surface 

is without rhizoids but is closely and usually strongly adherent to 

the substratum. Internally, it is composed of small cuboidal cells 

in vertical rows. Basal rows are composed of small cylindrical 

cells, tightly crowded together. Erect rows (filaments) of the 

upper layers are composed of elongate cylindrical cells that form 

a cortex, with secondary pit connections usually present between 

cells. Ultrastructurally, the pit plugs have a single cap layer.

Vegetative reproduction is by propagules in freshwater species and apparently not by spores. Tetrasporangial conceptacles, 

the only known reproductive structures, are developed below the 

thallus surface in marine species, with tetrasporangia being continuously produced from the repeated conversion of vegetative 

cells of the surrounding conceptacle walls. Tetrasporangia are 

transversely to obliquely zonate or irregularly divided. Gametophytes are unknown.

Remarks. The Hildenbrandiaceae is generally recognized to include two genera: the presumably cosmopolitan 

Hildenbrandia and Apophlaea J. D. Hooker et Harvey (1845; see 

Saunders and Bailey, 1999), known from New Zealand and the 

sub-Antarctic islands. The species are almost exclusively marine, 

found from the high intertidal to subtidal in tropical to subpolar 

waters, but there is at least one widely distributed freshwater 

species (Sheath, 2003; Sherwood and Sheath, 2003). 

Fungal hyphae of Mycosphaerella Johanson (1885; Ascomycetes) are often found penetrating the cell walls and into the 

conceptacle chambers of Hildenbrandia and Apophlaea (Kohlmeyer and Demoulin, 1981; Hawkes, 1983). Species of Mycosphaerella have also been described in other marine algae (e.g., 

Johnson and Sparrow, 1961), and the possible symbiotic fungalalga association (Kohlmeyer and Hawkes, 1983) is apparently 

more common in the high intertidal. Other fungal-alga or fungalcyanobacteria associations in marine habitats include members 

of the order Verrucariales Mattick ex D. Hawksworth et O. E. 

Erkisson (1986; Ascomycota, Eurotiomycetes), lichenized and 

nonlichenized fungi (Fletcher, 1980; Hawksworth, 2000), with 

some of the species found in coastal regions of Baja California 

and Sonora (e.g., Breuss and Bratt, 2000; Breuss, 2001). Other 

interesting marine fungal–alga associations on the eastern Pacific 

coast are found in the green alga Blidinga minima var. vexata

(Setchell et N. L. Gardner) J. N. Norris (1971) from Alaska to 

California, and between a brown alga Petroderma maculiforme

(Wollny) Kuckuck (1897; Wynne, 1969) and the lichen Verrucaria tavaresiae Moe (1997; Saunders et al., 2004), which occurs 

from Washington to California (Scagel et al., 1989) and Guerrero (Pedroche et al., 2008). 

Hildenbrandia is the only genus of the Hildenbrandiaceae 

found in the Gulf of California.

Hildenbrandia Nardo

Hildenbrandia Nardo, 1834:676 [as “Hildenbrandtia”]; Pueschel, 1982:333; 

1988b:25; 1989:625.

Algae are prostrate, coriaceous, noncalcified crusts, with 

smooth surfaces, and are usually irregular in outline. These 

firm crusts spread outward by peripheral growth, and their 

lower surface, without rhizoids, is strongly attached to the 
3 6 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

substratum. Anatomically, they are composed of small cells 

that are cylindrical or occasionally elongated in the direction 

of growth and in uneven or horizontal rows (horizontal stratification of the thallus is sometimes apparent). The hypothallus 

or basal layer is composed of firmly united, radially branched, 

horizontally spreading filaments; secondary pit connections are 

abundant (Pueschel, 1982, 1988b). The basal layer gives rise to 

the perithallus (upper layers), which is composed of compacted, 

vertical (erect) rows of sparsely branched filaments that adhere 

laterally to each other and form a pseudoparenchyma that is 

divided into transverse layers. Cells are cylindrical, mostly ~5 

μm in diameter, uninucleate, with a single chloroplast. Adjacent cells of the filaments are joined by secondary pit connections, which are often abundant (Pueschel, 1988b). Pit plugs 

are unique in that they have a cap membrane but lack an outer 

cap layer. 

Tetrasporangia are zonate, transversely to obliquely divided, but sometimes appearing cruciate or irregularly divided, 

and develop from the walls and floors of rounded to ovate, 

ostiolate conceptacles within the perithallus. The round to ovate 

or cylindrical conceptacle chambers become enlarged by repeated 

rounds of the conversion of vegetative cells lining the walls and 

floor into tetrasporangia. Conceptacles are with or without paraphyses. Sexual reproduction has not been convincingly shown 

for species of Hildenbrandia (Irvine and Pueschel, 1994), and 

gametangial structures remain unknown.

Remarks. There is one Pacific Mexico species, Hildenbrandia dawsonii (Ardré) Hollenberg (1971b; basionym: H. 

canariensis var. dawsonii Ardré, 1959), described from Punta 

Malamarrimo, Bahía Sebastián Vizcaíno, Baja California, that 

has been reported from San Juan Islands, Washington, to Baja 

California Sur (Abbott and Hollenberg, 1976) and in the southern Gulf of California from Nayarit to Jalisco (León-Álvarez and 

González-González, 1993; Mateo-Cid and Mendoza-González, 

1992; Mendoza-González and Mateo-Cid, 1992; Mateo-Cid 

and Mendoza-González, 1994b).

Two species of Hildenbrandia are recognized in the northern Gulf of California.

KEY TO THE SPECIES OF HILDENBRANDIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Crusts usually dark reddish brown to blackish; 250–450 μm thick; tetrasporangia irregularly divided, borne within 

immersed subspherical to compressed (wider than tall) conceptacles, with conspicuous paraphyses . . . . . H. prototypus

1b. Crusts lighter in color, rose to red; thinner, (50–)80–250 μm thick; tetrasporangia obliquely cruciate or irregularly divided, 

borne within immersed ovate conceptacles, without paraphyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. rubra

Hildenbrandia prototypus Nardo

FIGURE 20

Hildenbrandia prototypus Nardo, 1834:676; Taylor, 1945:166; Dawson, 1953a:95, pl. 7: fig. 4; 1959a:20; 1961b:413; 1966a:17; Denizot, 1968:196, fig. 196; Umezaki, 1969:17, fig.1; Huerta-Múzquiz 

and Tirado-Lizárraga, 1970:127; Chávez-Barrear, 1972b:269; 

Huerta-Múzquiz and Garza-Barrientos, 1975:8,12; Abbott and 

Hollenberg, 1976:377 [in part; excluding H. rosea]; DeCew and 

West, 1977a:31, figs. 3–5, 8, 9; Huerta-Múzquiz, 1978:340; 

Pueschel and Cole, 1982:709, fig. 17; Schnetter and Bula-Meyer, 

1982:123, pl. 16: fig. C; Huerta-Múzquiz and Mendoza-González, 

1985:48; Ramírez and Santelices, 1991:228; Stewart, 1991:77; 

León-Álvarez and González-González, 1993:461 [in part]; 

González-González et al., 1996:317, 397; CONANP, 2002:141; 

Fernández-García et al., 2011:62.

Hildenbrandia rosea sensu Setchell and Gardner, 1924:787; Dawson, 

1944a:265 [in part]; González-González et al., 1996:226 [non H. rosea

Kützing, 1843:384, which is now Hildenbrandia rubra (Sommerfelt) 

Meneghini, 1841:426].

Algae crustose, reddish brown to blackish, spreading up to 

2 cm, with a smooth surface; 250–450 μm thick; lower surface 

closely adherent to substratum, rhizoids lacking. Cells of erect 

filaments, squarish to slightly elongated, (2.5–)3–5 μm in diameter, arranged in compact vertical rows; secondary pit connections present.

Tetrasporangia irregularly divided, 15–22 μm long by 

3.5–6.5 μm in diameter. Tetrasporangia borne inside immersed, 

FIGURE 20. Hildenbrandia prototypus: Vertical section through 

crust showing a tetrasporangial conceptacle with irregularly divided 

sporangia among paraphyses (after Dawson, 1953a: pl. 7, fig.4). 
NUMBER 96 • 3 7

subspherical to compressed (wider than tall), ostiolate conceptacles, 35–110 μm wide by 35–60 μm deep; with conspicuous 

paraphyses.

Habitat. On rocks; high to low intertidal.

Distribution. Gulf of California: Puerto Peñasco; 

Isla Turner, off SE end of Isla Tiburón (Islas de la Cintura); Isla 

Carmén; Cabeza Ballena; Nayarit to Jalisco; Isla María Magdalena and Isla María Cleofas (Islas Marías; Islas Tres Marias). 

Eastern Pacific: Alaska to Baja California; Isla Socorro and Isla 

Clarión (Islas Revillagigedo); Jalisco to Oaxaca; El Salvador; 

Costa Rica; Panama to Colombia; Galápagos Islands; Chile.

Type Locality. Venezia, shore of Adriatic Sea, 

northeast Italy (Smith, 1944).

Remarks. Some have considered Hildenbrandia prototypus and H. rubra to be conspecific (e.g., Denizot, 1968) or H. 

prototypus to be conspecific with H. rosea Kützing (1843) (e.g., 

Abbott and Hollenberg, 1976). However, Irvine and Pueschel 

(1994) listed H. prototypus as a doubtful synonym of H. rubra

since the type is unknown, and the tetrasporangial cleavage was 

not given in the original description of Nardo (1834). Thus, the 

taxonomic status of H. prototypus is somewhat uncertain. Until 

specimens, including types, can be critically studied, the Gulf 

material herein referred to H. prototypus differs in being thicker 

than H. rubra, (250–)270–500 μm, and dark reddish brown to 

blackish. Dawson (1953a) noted the cell sizes of Pacific Mexico 

H. prototypus were somewhat smaller than those reported from 

elsewhere in the world.

Hildenbrandia rubra (Sommerfelt) Meneghini

Verrucaria rubra Sommerfelt, 1826:140.

Hildenbrandia rubra (Sommerfelt) Meneghini, 1841:426; Denizot, 1968:199; 

Pueschel and Cole, 1982:333, figs. 1–2, 17; Dethier, 1987:1842, fig. 

8; Pueschel, 1988a:17, figs. 1–6; Mendoza-González and Mateo-Cid, 

1992:17; León-Álvarez and González-González, 1993:461 [in part]; 

Serviere-Zaragoza et al., 1993a:483; León-Tejera et al., 1993:200; 

Mateo-Cid et al., 1993:47; Irvine and Pueschel, 1994:241, figs. 117B, 

118B; Mateo-Cid and Mendoza-González, 1994b:39; MendozaGonzález et al., 1994:105; González-González et al., 1996:397; Sherwood and Sheath, 1999:525; L. Aguilar-Rosas et al., 2000:130; Müller 

et al., 2005b:380; Mateo-Cid et al., 2006:55; Serviere-Zaragoza et al., 

2007:10.

Hildenbrandia prototypus sensu Taylor, 1945:166 [in part]; Dawson, 

1953a:95 [in part]; 1966a:17 [non Hildenbrandia prototypus Nardo, 

1834:676].

Thallus crustose, noncalcified, rose to dark red, thin, (50–)

80–250 μm thick, and spreading up to 12 cm across, irregular in 

outline; upper surface more or less smooth; lower surface tightly 

adherent to substratum, rhizoids absent. Erect filaments, up to 

100 μm long, of 10–30 cells arranged in compact, more or less 

vertical rows. Cells of perithallus, squarish to slightly elongated, 

2.5–5.0 μm in diameter by 2.5–6.0(–7.0) μm tall; secondary pit 

connections present.

Tetrasporangia obliquely cruciate or irregularly divided, 

15–25(–35) μm long by 8.0–12(–15) μm in diameter; borne 

within immersed, ovate conceptacles, 80–90 μm wide by 65–70 

μm deep; paraphyses lacking.

Habitat. On rocks; mid intertidal to shallow 

subtidal.

Distribution. Gulf of California: Bahía La Choya 

(Bahía Cholla, vicinity of Puerto Peñasco); San Felipe to Bahía 

de Los Ángeles; Cabeza Ballena; Mazatlán, Sinaloa to Nayarit. 

Eastern Pacific: British Columbia to Oregon; Playa Los Cerritos 

(south of Todos Santos), Baja California Sur; Isla Socorro, Isla 

Clarión and Isla San Benedicto (Islas Revillagigedo); Michoacán 

to Oaxaca; Costa Rica; Panama; Galápagos Islands.

Type Locality. Saltdal, Nordland, Norway (“in 

lapidibus a fluxu maris inundatis ad litora Nordlandiae frequenter” [Sommerfelt, 1826:140]).

Remarks. The thin, mostly rose red to brownish red, 

Gulf of California specimens of Dawson (1953a, 1966a, both as 

“H. prototypus”) are herein referred to H. rubra. Hildenbrandia 

rosea is sometimes accepted as a synonym of H. rubra (e.g., Silva 

et al., 1996a). However, Irvine and Pueschel (1994) listed both

H. rosea and H. prototypus as doubtful synonyms of H. rubra. 

The type of H. prototypus is unknown, and its tetrasporangial 

cleavage was not given in the original description (Nardo, 1834), 

and the type of H. rosea Kützing (1843) was nonreproductive. 

Thus, the status of these taxa is uncertain, and Gulf specimens 

identified as “H. prototypus,” “H. rosea,” or “H. rubra,” need 

to be critically reinvestigated taxonomically, in culture, and 

tested with DNA analyses with type locality materials.

Although another eastern Pacific species, H. occidentalis

Setchell in Gardner (1917), described from northern California 

and reported from Alaska to Baja California, is recognized as a 

separate taxon by several phycologists (e.g., Abbott and Hollenberg, 1976; DeCew and West, 1977a; Dethier, 1987; Pueschel, 

1988b; Scagel et al., 1989), Sherwood and Sheath (1999) found 

its separation from H. rubra was only partially supported.

NEMALIOPHYCIDAE

Nemaliophycidae T. A. Christensen, 1978:66; Guiry and Irvine, 1989:155; 

G. W. Saunders et Hommersand, 2004:1504; Schneider and Wynne, 

2007:201.

Members of the subclass Nemaliophycidae are characterized by generally having a triphasic life history, and ultrastructurally, they have pit plugs with two cap layers.

Remarks. Recently, new orders and families were 

added to the Nemaliophycidae: Balliales H.-G. Choi, Kraft et 

G. W. Saunders (2000), Colaconematales J. T. Harper et G. W. 

Saunders (2002), Thoreales K. M. Müller, Sheath, A. R. Sherwood et Pueschel (in Müller et al., 2002), and on the basis of 

a new unique acrochaetioid algal genus, Rhodachlya, the Rhodachlyales G. W. Saunders, S. L. Clayden, J. L. Scott, K. A.West, 

U. Karsten et J. A.West (in West et al., 2008). 

The subclass Nemaliophycidae is represented by four of its 

orders in the northern Gulf of California.
3 8 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

KEY TO THE ORDERS OF THE NEMALIOPHYCIDAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Algae filamentous, crusts of laterally fused filaments and erect fronds; life history diphasic, lacking a carposporophyte; 

single-cell carpogonium after fertilization directly produces tetrasporangial thallus; tetrasporangia repeatedly regenerated 

from a basal generative stalk cell (unique to the order); monosporangia not known . . . . . . . . . . . . . . . . . . . Palmariales

1b. Algae either of uniseriate filaments or multiaxial with medullary and cortical layers; life histories triphasic or biphasic, 

with isomorphic, dimorphic, or heteromorphic phases; monosporangia present or absent . . . . . . . . . . . . . . . . . . . . . . 2

2a. Algae structurally complex (not a single row of axial cells); of filamentous medulla and cortex of loose anticlinal filaments, or compact, laterally adjoined filaments, or of cells fused to form a pseudoparenchymatous cortex; life histories 

triphasic with isomorphic, dimorphic, or heteromorphic phases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nemaliales

2b. Algae simple, unbranched to branched, uniseriate filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Uniseriate filaments of two different kinds of members: one group has cells with 1 to several, discoid to band-shaped, 

parietal plastids without pyrenoids, tetrasporangia (monosporangia unknown), and biphasic life history; second group 

has cells with a single, stellate plastid and a central pyrenoid, primarily monosporangia, and triphasic life history. . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acrochaetiales

3b. Uniseriate filaments of cells with 1 or more lobed, spiral, or irregular (never stellate) parietal plastids, and with or wthout 

pyrenoids; monosporangia, life histories biphasic or triphasic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Colaconematales

Acrochaetiales

Acrochaetiales Chemin, 1937:300.

Acrochaetiales Feldmann, 1953:12; Harper and Saunders, 2002:470 

[emended description].

Algae are composed of uniseriate simple or branched filaments. Members occur in marine or freshwater habitats. There 

are two groups of marine species. Members of the first group 

have cells that may contain one but usually have several parietal discoid to band-shaped chloroplasts per cell and lack pyrenoids (i.e., Rhodochorton Nägeli, 1862); monosporangia are 

unknown in these members, asexual reproduction is primarily by 

tetrasporangia, and sexual reproduction, where known, involves 

a biphasic life history. In the second group each cell has a single 

stellate chloroplast with a single central pyrenoid; reproduction 

is primarily by monosporangia, and sexual reproduction, where 

known, involves a triphasic life history.

Members of the one family are known to occur in the Gulf 

of California.

Acrochaetiaceae

Acrochaetiaceae Fritsch ex W. R. Taylor, 1957:209–210, nom. cons.

Acrochaetiaceae Fritsch, 1944:258 [footnote], nom. nudum; Fritsch, 

1945:737 [see Silva, 1980:20].

Chantransiaceae Kützing, 1843:180 [not including Chantransia; see Silva, 

1952:261].

Rhodochortaceae Nasr, 1947:92, nom. rej.

Members of this family are mostly minute, uniseriate branched 

filaments, growing epiphytically, endophytically, or endo–epiphytically on various algae and sea grasses, endozoic or epizoic on 

invertebrates, or on hard substratum. Cells of the filaments are uninucleate and contain one chloroplast with one pyrenoid.

Asexual reproduction in most of the species is by monospores, but in some, it is by bispores or tetraspores. Sporangia are 

borne laterally or terminally. In some, the tetrasporophyte develops directly from the fertilized carpogonium (Stegenga, 1978). 

Sexual reproduction is apparently rare, and gametophytes are 

known in only a few genera (Abbott, 1962). The female reproductive apparatus is a one- to three-celled carpogonial branch. 

After fertilization the short-branched gonimoblast filaments 

produce carposporangia terminally. Cystocarps are exposed and 

naked without a surrounding envelope. Spermatangia are clustered on short-branched filaments.

Culture studies within this family have shown many interesting life histories (e.g., Stegenga, 1985b), with isomorphic 

and heteromorphic phases. Some culture studies have shown 

“Acrochaetium-like” phases to be involved in life histories of 

other, morphologically dissimilar species or even different genera 

(some even in other families). One of the earlier studies revealed 

an Acrochaetium-like phase of Ganonema farinosum (Liagoraceae) (von Stosch, 1965, as Liagora farinosa). 

The Acrochaetiaceae is represented by one genus in the 

northern Gulf of California.

KEY TO THE UNISERIATE FILAMENTOUS RED ALGAE: GENERA OF ACROCHAETIACEAE 

(ACROCHAETIALES), COLACONEMATACEAE (COLACONEMATALES), AND 

RHODONEMATELLACEAE (PALMARIALES) IN THE NORTHERN GULF OF CALIFORNIA

1a. Cells of filaments with stellate chloroplasts containing a pyrenoid; asexual reproduction by monosporangia . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Acrochaetium (Acrochaetiaceae)

1b. Cells of filaments with a single parietal chloroplast or rarely with several parietal plastids . . . . . . . . . . . . . . . . . . . . . . 2
NUMBER 96 • 3 9

2a. Cells with a single parietal chloroplast and 1 pyrenoid; asexual reproduction by monosporangia . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Colaconema (Colaconemataceae)

2b. Cells with more than 1 parietal chloroplast, without pyrenoids; asexual reproduction by tetrasporangia (monosporangia 

lacking) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rhodonematella (Rhodonematellaceae)

Acrochaetium Nägeli

Acrochaetium Nägeli in Nägeli et C. E. Cramer, 1858:532; Harper and Saunders, 2002:470.

Algae are uniseriate filaments that are mostly microscopic, 

sometimes minute, and either epiphytic, endophytic, or endoepiphytic (partly embedded within their alga host) or epizoic 

or endozoic on various invertebrates (notably hydrozoans, 

sponges, or mollusks) or growing on rocks or other hard substratum. Erect filaments are simple and unbranched or may 

be variously branched, irregular, secund, or opposite. Branch 

ends of some species may occasionally bear terminal unicellular 

hairs. Gametophytes are attached by a single cell or a monostromatic base. Cells contain a single stellate chloroplast with a 

central pyrenoid. 

Life histories, where known, are triphasic, involving heteromorphic phases of sporophytes and gametophytes. Asexual 

reproduction is mainly by spherical monosporangia, borne terminally or laterally. In many species monospores are the only 

form of propagation known. Tetrasporangia, where known, are 

cruciately divided and terminal or lateral on erect filaments and 

branches. Sexual reproduction is apparently rare or unknown in 

many species. Gametophytes are monoecious or dioecious. Carpogonia (where known) are one-celled (lack a distinct carpogonial filament) and sessile or pedicellate. Postfertilization zygote 

does not divide but directly produces a small, globose carposporangium. Spermatangia produced in small clusters, with one to 

several spermatangia, and borne on long, hyaline stalks.

Remarks. In the past Acrochaetium was generally accepted to represent a “form genus” in which, for convenience, 

species that resembled each other were all placed together within 

a broadly defined single genus, Audouinella Bory de SaintVincent (1823) by Woelkerling (1973a, 1973b). On the basis of 

the species studied, Pueschel (1989, 1990) concluded that they 

were polyphyletic. Acrochaetium has now been restricted to marine species that reproduce chiefly by monosporangia and contain 

stellate plastids (Y.-P. Lee and Lee, 1988); this generic concept 

has been supported by molecular analyses (Harper and Saunders, 

2002). The freshwater species now are placed in Audouinella.

Dixon (1963) first suggested some members of the “Acrochaetium assemblage” may represent phases in the life history of 

other red algae. Since then, sporophytic Acrochaetium-like phases 

were grown from the germination of carpospores of Liagora and 

Ganonema species (von Stosch, 1965; Couté, 1971; Guiry and 

Irvine, 1989; Guiry, 1990a; Brodie and Norris, 1996) and species of Tricleocarpa (Magruder, 1984, as Galaxaura). Life history summaries have been provided by Hoshaw and West (1971), 

Dixon (1973), Norris and Kugrens (1982), and Hawkes (1990).

Further collections are needed for reevaluation of the species 

recorded in the Gulf of California in light of studies by Woelkerling (1971), Stegenga (1985b), Y.-P. Lee and Yoshida (1997), and 

Harper and Saunders (2002). Culture and DNA studies on Gulf 

of California species should further clarify their life histories and 

generic and specific status.

Presently, seven species of Acrochaetium are known in the 

northern Gulf of California. 

KEY TO THE SPECIES OF ACROCHAETIUM (ACROCHAETIALES; ACROCHAETIACEAE) 

AND RHODONEMATELLA (PALMARIALES; RHODOPHYSEMATACEAE) 

IN THE NORTHERN GULF OF CALIFORNIA

1a. Cells of filaments with parietal plastids (without pyrenoids); endo-epiphytic in/on Gulf of California foliose reds, Halymenia and Kallymenia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rhodonematella subimmersa

1b. Cells of filaments with a stellate plastid containing a single pyrenoid; epiphytic, endophytic, or endo-epiphytic on various 

algae and sea grasses (species of Acrochaetium) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Filaments entirely endophytic Porphyra or Asparagopsis; originating from two hemispherical cells . . . . . A. porphyrae

2b. Filaments may be partially endo-epiphytic or entirely epiphytic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Filaments partially endophytic; creeping on host surface and sometimes between cortical cells of algal host A. bornetii

3b. Filaments epiphytic; attached to surface layer of the alga host . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

4a. Basally attached by a prostrate single layer of cells (monostromatic) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4b. Attached by a single basal cell (not a prostrate monostromatic layer of cells) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5a. Branching mostly secund, sometimes alternate; filaments 600–800 μm in length . . . . . . . . . . . . . . . . . . . . A. seriaspora

5b. Unbranched or only sparsely branched in lower portion, abundantly branched above; filaments longer, up to 1.5 mm in 

length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. secundatum

6a. Initial basal cell produces prostrate filaments; entire thallus adheres to host surface, or with some upper branched 

filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. microscopicum

6b. Initial basal attachment remains a single cell, with erect filament(s) growing from it . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4 0 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

7a. Filament branching alternate or secund; monosporangia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. arcuatum

7b. Filament branching at first secund, later opposite, sometimes slightly arching; terminal monosporangia . . . . A. crassipes

Acrochaetium arcuatum (K. M. Drew) C. K. Tseng

FIGURE 21A

Rhodochorton arcuatum K. M. Drew, 1928:165, pl. 37: figs. 1–3; Dawson, 

1944a:255; González-González et al., 1996:264. 

Acrochaetium arcuatum (K. M. Drew) C. K. Tseng, 1945:158, pl. 1: fig 1; 

Abbott and Hollenberg, 1976:310, fig. 251; Silva, 1979:316; Hawkes 

et al., 1978:96; Harper and Saunders, 2002:470. 

Kylinia arcuata (K. M. Drew) Kylin, 1944:13; Papenfuss, 1947a:436; Dawson, 1953a:31; 1961b:405; Norris and West, 1967:112; Perestenko, 

1996:45, pl. 6: figs. 10–12. 

Chromastrum arcuatum (K. M. Drew) Papenfuss, 1945:321. 

Audouinella arcuata (K. M. Drew) Garbary, G. I. Hansen et Scagel, 1983:12, 

fig. 2; Hansen and Garbary, 1984:174, figs. 1–9; Garbary, 1987:21; 

Scagel et al., 1989:144; González-González et al., 1996:175.

Algae epiphytic; erect filaments usually singular, occasionally 2 or more; at acute angles from host alga or sometimes almost decumbent; attached to host by a single, large, subglobose 

basal cell. Filaments up to 100 μm long, 5.0–5.5 μm in diameter, 

with irregularly secund or alternate branchlets; terminal cells 

may have long, hyaline hair-like cells. Cells mostly 7.5–8.5 μm in 

length, with a stellate plastid and a central pyrenoid.

Monosporangia borne lateral and terminal on main axis 

and branchlets. Sexual reproduction unknown.

Habitat. Epiphytic on Sphacelaria; intertidal.

Distribution. Gulf of California: Isla Turner (off 

SE end of Isla Tiburón). Eastern Pacific: Alaska to central California; Michoacán. Western Pacific: China (Hong Kong).

Type Locality. Epiphytic on Pterosiphonia spp. 

and Polysiphonia sp.; Moss Beach, San Mateo County, central 

California, USA.

Acrochaetium bornetii Papenfuss

Acrochaetium bornetii Papenfuss, 1945:313 [new name for Chantransia 

corymbifera Thuret (in Le Jolis, 1863b:107), which was based on two 

separate entities: Bornet et Thuret, 1876:16, pl. 5]; Dawson, 1953a:23; 

1961b:403; Garbary, 1987:29; González-González et al., 1996:166 

[non Acrochaetium corymbiferum (Thuret in Le Jolis, 1863b:107, pro 

parte) Batters, 1902:59]. 

FIGURE 21. Species of Acrochaetium. A. Acrochaetium arcuatum: Mature thallus showing branching, monosporangia, and terminal spermatangia (after Drew, 1928: pl. 37, fig. 2, as Rhodochorton arcuatum). B, C. Acrochaetium porphyrae: B. An endophytic filament in host 

Porphyra issuing free erect branches, some bearing monosporangia. C. Germinating spore showing filaments bending down into the host that 

have developed from the two daughter cells of the spore (after Drew, 1928: pl. 46, figs. 71, part of 75, as Rhodochorton porphyrae). D–F. 

Acrochaetium secundatum: D. Filament with elongated, hair-like cells. E. Young filament (D, E after Kylin, 1944, fig. 11). F. Filament cells with 

stellate chloroplasts (after Dawson, 1953a: pl. 1, fig. 3, as Kylinia secundata). G–J. Acrochaetium seriaspora: Portions of several filaments of the 

type collection showing both solitary and seriate production of tetrasporangia (after Dawson, 1953a: pl. 2, figs. 2–5, type collection of Kylinia 

seriaspora). 
NUMBER 96 • 4 1

Acrochaetium savianum sensu L. Aguilar-Rosas et al., 2000:130 [in part] 

[non Acrochaetium savianum (Meneghini) Nägeli, 1862:405, 414].

Algae endo-epiphytic; with erect branched filaments, up to 

2 mm in length; of cells 6–7 μm in diameter, 30–70 μm long; 

branches few in lower portion, upper portions with many alternate to more or less secund branches.

Monospores ovate, 7–8 μm in diameter; sessile and singular, 

or 2–3 on a 1-celled pedicel. Gametophytes dioecious. Carposporangia and spermatangia in clusters, on short pedicels.

Habitat. On “Helminthocladia” (L. Aguilar-Rosas et 

al., 2000, as “A. savianum”); low intertidal to shallow subtidal.

Distribution. Gulf of California: Puertecitos. 

Eastern Pacific: San Pedro, southern California; Punta Pequeña, 

Bahía San Juanico, Baja California Sur.

Type Locality. On Helminthocladia (see Thuret in 

Bornet et Thuret, 1876:16, pl. 5); Belle-Ile-en-Mer, Morbihan, 

Brittany, northwest France.

Remarks. Some have treated Acrochaetium bornetii

as a synonym of A. savianum (Meneghini) Nägeli (1862) (e.g., 

Wynne, 2005). Herein I follow Garbary (1987:29, 163) in recognizing these two as separate species, until the taxonomy of the 

Gulf species can be clarified. 

Acrochaetium crassipes (Børgesen) Børgesen

FIGURE 22

Chantransia crassipes Børgesen, 1909:1, fig. 1.

Acrochaetium crassipes (Børgesen) Børgesen, 1915:20, figs. 11–13; Yendo, 

1917:201; Taylor, 1928:134, pl. 28: fig. 16; Tseng, 1945:157; PhạmHoáng, 1969:86, fig. 2.18; Tanaka and Hirose, 1971:111; Kajimura, 

1979:99; Pacheco-Ruíz et al., 2008:206.

Kylinia crassipes (Børgesen) Kylin, 1944:13; Papenfuss, 1947a:436; Dawson, 

1953a:31; 1961b:405; 1963c:5.

Chromastrum crassipes (Børgesen) Papenfuss, 1945:321; Stegenga and Mulder, 1979:305, fig. 41; Stegenga and Kemperman, 1983:72, figs. 20–24. 

Audouinella crassipes (Børgesen) Garbary, 1979:478, 490; 1987:49. 

Rhodochorton microscopicum sensu Dawson, 1944a:254, pl. 41: fig. 3; 

González-González et al., 1996:264 [non Rhodochorton microscopicum (Nägeli ex Kützing) K. M. Drew, 1928:163, which is now Acrochaetium microscopicum (Nägeli ex Kützing) Nägeli in Nägeli and 

Cramer, 1858:532].

Algae epiphytic; of 1 or rarely 2 uniseriate filaments, abundantly branched; attached below by a single subglobose basal 

cell. Young thalli with short, 1- to 3-celled, secundly arranged 

branchlets; mature thalli usually with opposite, longer branches; 

branches or branchlets from almost every cell except the basal 

cell and terminal cells. Filaments frequently slightly arched. Apical cells occasionally with a long hyaline hair.

Monosporangia mostly terminal on short branchlets. Sexual 

reproduction unknown. 

Habitat. Epiphytic on Polysiphonia, Gelidium, and 

probably other algae; intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Isla Turner (off SE end of Isla Tiburón); Isla Rasa (with a 

query). Eastern Pacific: Bahía Sebastián Vizcaíno, Baja California Sur; Galápagos Islands.

Type Locality. Harbor, St. Thomas, U.S. Virgin Islands, Caribbean Sea.

Remarks. Specimens from Isla Rasa (Isla Raza; 

“Flat Island”) were noted as probably belonging to Acrochaetium crassipes by Dawson (1953a, as “K. crassipes”). On the 

 FIGURE 22. Acrochaetium crassipes: A, B. Habits of two minute epiphytes, each with a main axis from a single basal cell, at first secundly then 

oppositely branched, filaments slightly arched (JN-4040b, epiphytic on Cladophora, US Alg. Coll. microscope slide 4254).
4 2 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

basis of our collections, A. crassipes may now be recorded in 

the upper Gulf (JN-4040b, US Alg. Coll. microscope slide 4254) 

from Playa Hermosa and Playa Las Conchas (Playa Estación) 

(JN-4082, US Alg. Coll. microscope slide 4962), both in the vicinity of Puerto Peñasco, Sonora. 

Woelkerling (1972, 1973a, as Audouinella crassipes) suggested Acrochaetium crassipes was synonymous with A. microscopicum. However, culture studies of A. crassipes (Stegenga and 

Mulder, 1979; Stegenga and van Wissen, 1979) revealed that although the gametophytes were similar looking in both, the two 

could be distinguished by the tetrasporophytes in their life histories, and Stegenga (1985b) has kept these two species separate (see also Garbary, 1987). For now, northern Gulf specimens 

are referred to A. crassipes until culture studies and molecular 

analyses can be carried out on Gulf material to ascertain their 

taxonomic and phylogenetic status.

Acrochaetium microscopicum (Nägeli ex Kützing) Nägeli

Callithamnion microscopicum Nägeli ex Kützing, 1849:640.

Acrochaetium microscopicum (Nägeli ex Kützing) Nägeli in Nägeli et 

C. E. Cramer, 1858:532; Nägeli, 1862:403, figs. 24, 25; Okamura, 

1932:87; Tseng, 1945:157; Hollenberg and Abbott, 1966:42, fig. 15; 

Lindstrom, 1977:86; Y.-P. Lee, 1987:30, fig. 14; Abbott, 1999:55, fig. 

3G; L. Aguilar-Rosas et al., 2000:130, 137; Mateo-Cid et al., 2000:63; 

L. Aguilar-Rosas et al., 2002:234; Mateo-Cid et al., 2006:55, 62; Y.-P. 

Lee, 2008:169, figs. A–D.

Chantransia microscopica (Nägeli ex Kützing) Berthold, 1882a:512.

Rhodochorton microscopicum (Nägeli ex Kützing) K. M. Drew, 1928:163; 

González-González et al., 1996:264.

Chromastrum microscopicum (Nägeli ex Kützing) Papenfuss, 1945:322; Stegenga and Kemperman, 1983:299, figs. 37–38(type material), 41.

Kylinia microscopicum (Nägeli ex Kützing) Kylin, 1944:13; Papenfuss, 

1947a:437; Dawson, 1953b:125; 1961b:405.

Audouinella microscopica (Nägeli ex Kützing) Woelkerling, 1971:9, 33, 

figs. 10, 23A; Garbary, 1979:479; Lindstrom et al., 1986:5; Garbary, 

1987:116; Scagel et al., 1989:147; Mateo-Cid and Mendoza-González, 

1997:56, pl. 1: fig. 2; Yoshida, 1998:465.

Algae minute epiphytes; with erect upper portions, up to 

40(–100) μm tall; covering area up to 250 μm on host’s surface; 

branched 1–3(–4) orders, with branches of similar or unequal 

length; original spore, 8.0 μm long and 7.0–8.0 μm in diameter, 

persisting after germination; attached by a basal cell directly to 

host’s surface layer or partly endophytic within host’s cortical 

cells. Cells squarish to barrel shaped, 6.0–9.0 μm tall and 8.0–12 

μm in diameter; with a stellate plastid and 1 pyrenoid. Terminal 

cells of filaments without or with hairs up to 55 μm long.

Monosporangia sessile or terminal, on short branchlets; 

20–24 μm in diameter. Sexual reproduction unknown.

Habitat. Epiphytic on Cladophora, Chaetomorpha, 

Sphacelaria, and Sargassum; intertidal.

Distribution. Gulf of California: Piedras del 

Burro (Gulfo de Santa Clara) to Puertecitos; Punta Arena (north 

of Cabo Pulmo). Eastern Pacific: Alaska to Bahía Sebastián 

Vizcaíno, Baja California; Oaxaca. Western Pacific: Korea; 

Japan.

Type Locality. “In sinu neapolitano” (Kützing, 1849); Golfo di Napoli, Italy, Mediterranean Sea (Silva et 

al., 1996a:99). Others have listed the type locality as Torquay, 

Devon, England, UK (Hamel, 1927, 1928; Woelkerling, 1972; 

Woelkerling and Womersley, 1994; Athanasiadis, 1996b), and 

the type in Kützing collections (L) is from England (Guiry and 

Guiry, 2012).

Remarks. Acrochaetium microscopicum was reported in the northern Gulf of California by L. Aguilar-Rosas et 

al. (2000) and Mateo-Cid et al. (2006). Although the species is

reportedly widespread in temperate to tropical seas (e.g., Børgesen, 1915, 1927, 1931; Taylor, 1960; Wynne, 2005), Garbary 

(1987) noted there is much confusion on the taxonomic identification and application of the epithet “microscopicum.” Some 

Pacific Mexico specimens may have been identified following the 

descriptions of “Acrochaetium microscopicum” by Hollenberg 

and Abbott (1966) and Abbott and Hollenberg (1976); however, 

Garbary (1987) noted that their descriptions of California material represent a different species.

Woelkerling (1972) suggested another species, A. crassipes,

was conspecific with A. microscopicum. On the basis of culture 

studies, Stegenga (1985b) noted that Woelkerling’s species concept was too broad and that similar-looking gametophytes were 

involved in the life histories of tetrasporophytes that could be 

differentiated. For now, the two are considered distinct entities, 

with both species recorded in the Gulf of California.

Acrochaetium porphyrae (K. M. Drew) G. M. Smith

FIGURE 21B,C

Rhodochorton porphyrae K. M. Drew, 1928:188, pl. 46: figs. 70–75.

Acrochaetium porphyrae (K. M. Drew) G. M. Smith, 1944:179, pl. 40: figs. 

8, 9; Sparling, 1971:237; Norris and Abbott, 1972:90; Abbott and 

Hollenberg, 1976:317, fig. 259; Silva, 1979:316; L. Aguilar-Rosas and 

Aguilar-Rosas, 1993:202.

Chromastrum porphyrae (K. M. Drew) Papenfuss, 1945:325.

Kylinia porphyrae (K. M. Drew) Papenfuss, 1947a:438; Dawson, 1953a:30; 

1961b:405.

Colaconema porphyrae (K. M. Drew) Woelkerling, 1971:9, 50, figs. 20, 27B.

Audouinella porphyrae (K. M. Drew) Garbary, 1979:479, 490; Garbary et 

al., 1983:42, fig. 17; Scagel et al., 1986:125; Tam et al., 1987:532, figs. 

1–19; Garbary, 1987:141; Scagel et al., 1989:148; Ramírez and Santelices, 1991:180; Womersley, 1994:71.

Algae endophytic; in the Gulf of California, forming small 

reddish patches within Asparagopsis. Filaments originating from 

two hemispherical cells (Figure 21C); branching irregularly, 

pinnately, and mostly divaricately; spreading prostrate on the 

surface and between cells of algal host; occasionally with erect 

branches of 1 or more cells, sometimes with short branchlets. 

Cells of endophytic filaments usually broader in middle and narrower at ends; to 10 μm in diameter; erect filament cells, 5–8 μm 

in diameter; with a stellate plastid and single central pyrenoid.
NUMBER 96 • 4 3

Monosporangia borne terminally and laterally on erect filaments and branchlets. Sexual reproduction unknown.

Habitat. Endo-epiphytic on Asparagopsis; subtidal, 

down to 5 m depths.

Distribution. Gulf of California: Puerto Calamajue. Eastern Pacific: southern Alaska to northern Baja California; 

Chile.

Type Locality. Land’s End, San Francisco, San 

Francisco County, northern California, USA. 

Remarks. Acrochaetium porphyrae is now reported 

in the northern Gulf of California. Specimens of this species, collected at Puerto Calamajue, Baja California (JN-4637b, US Alg. 

Coll. microscope slide 4259), were growing on Asparagopsis

taxiformis, apparently a new host for this species. Elsewhere in 

the northeastern Pacific, this endo-epiphyte is most commonly 

found on Porphyra (Abbott and Hollenberg, 1976). It had been 

reported in central California (Smith, 1944; Sparling, 1971) 

and from Bahía San Quintín, Pacific Baja California (Dawson, 

1953a), and it was later reported from Hope Island, off the 

northern end of Vancouver Island, British Columbia (Norris and 

Abbott, 1972). 

Acrochaetium secundatum (Lyngbye) Nägeli

FIGURE 21D–F

Callithamnion daviesii (Dillwyn) Nägeli b [var.] secundatum Lyngbye, 

1819:129, pl. 41: figs. β4–β6 [note figs. β4–β6 chosen as lectotype by 

Woelkerling, 1983a:65].

Acrochaetium secundatum (Lyngbye) Nägeli in Nägeli et Cramer, 1858:532 

[footnote]; Nägeli, 1862:405; Collins, 1906b:194; Kylin, 1944:19, 

fig. 11; Tokida, 1960:92; Stegenga, 1985b:305, figs. 10, 11; Y.-P. Lee, 

1987:36, fig. 18; Perestenko, 1996:46, pl. 6: figs. 8, 9; Nielsen et al., 

1995:4; González-González et al., 1996:167.

Ceramium secundatum (Lyngbye) C. Agardh, 1824:132.

Callithamnion secundatum (Lyngbye) C. Agardh, 1828:187.

Chantransia secundata (Lyngbye) Thuret in Le Jolis, 1863b:106.

Chromastrum secundatum (Lyngbye) Papenfuss, 1945:323.

Kylinia secundata (Lyngbye) Papenfuss, 1947a:437; Dawson, 1953a:32, pl. 

1: fig. 3; 1957b:112, figs. c, d; Taylor, 1957:214, pl. 31: figs. 1–3; Dawson, 1961b:405; González-González et al., 1996:231.

Colaconema secundatum (Lyngbye) Woelkerling, 1973a:94, figs. 7, 8.

Audouinella secundata (Lyngbye) P. S. Dixon in Parke et Dixon, 1976:590; 

Dixon and Irvine, 1977a:114, fig. 39A–C; Woelkerling, 1973b:575, 

figs. 77–83; Garbary, 1978:218, figs. 33, 34; 1979a:952; 1979c:479; 

Woelkerling, 1983a:65, 81, figs. 5, 6; Garbary, 1987:166; GonzálezGonzález, 1993:441; Yoshida, 1998:469.

Algae epiphytic, erect filaments, arising from a prostrate, 

monostromatic base developed from an initial monospore and 

forming a layer of compacted cells on (and sometimes between) 

the host cells. Filaments up to 1.5 mm long, 5–8 μm in diameter; 

branching sparse or absent in lower portions; more abundant 

above; hair-like cells often extending from upper branches. Cells 

(5–)8–24 μm long, with a stellate plastid, and a single large pyrenoid located distally.

Monospores ovoid, to 6 μm diameter, usually pedicellate or 

occasionally sessile. Tetrasporangia and sexual reproduction unknown in Gulf material.

Habitat. Rocky reef, epiphytic on Sargassum, also 

often found growing with Colaconema punctatum; intertidal.

Distribution. Gulf of California: Bahía Bocochibampo (vicinity of Guaymas); Nayarit. Western Pacific: Russia; 

Korea; Japan; Vietnam; Enewetak Atoll (Eniwetok), Marshall 

Islands (Micronesia).

Type Locality. Kvivig (Kvívík), Streymoy Island, 

Faroe Islands (Faeroe; Føroyar), Farö County, Denmark.

Remarks. Acrochaetium secundatum is known only 

in the northern Gulf by the report of a single collection from Sonora (Dawson, 1953a). A cold water species, its presence in the 

Gulf of California requires more collections and further study.

Garbary (1987, as “Audouinella secundata”) noted that 

specimens of Acrochaetium secundatum from the northeast Pacific are probably misidentified and represent other species. Although Woelkerling (1973b:575, as “Colaconema secundata”) 

had suggested that this taxon “will be transferred to Audouinella,” he later designated Acrochaetium secundatum as the lectotype species for the genus Acrochaetium (Woelkerling, 1983a). 

(See also Remarks under Colaconema tenuissimum.)

Acrochaetium seriaspora (E. Y. Dawson) J. N. Norris, comb. nov.

FIGURE 21G–J

Kylinia seriaspora E. Y. Dawson, 1953a:32, pl. 2: figs. 2–5; 1961b:405; 

González-González et al., 1996:231.

Audouinella seriaspora (E. Y. Dawson) Garbary, 1987:170.

Chromastrum seriasporum (E. Y. Dawson) Stegenga et Mulder, 1979:305.

Algae epiphytic; of erect, branched filaments, arising from a 

monostromatic base of several to many cells, with some penetrating between the host’s cells. Filaments branching mostly secund, 

sometime alternate; erect filaments 600–800 μm long by 5–7 μm 

in diameter; cells 10–28 μm long, with a stellate chloroplast and 

a single, large pyrenoid.

Monosporangia ovoid, to 6 μm in diameter, usually borne 

on 1-celled pedicels in secund series. Tetrasporangia ovoid, 7–8 

μm in diameter; sessile, borne lateral on branch or terminal or 

lateral on 1- to 2-celled pedicels on branches (Figure 21G). Sexual reproduction unknown. 

Habitat. Epiphytic on Sargassum; intertidal.

Distribution. Gulf of California: Isla Turner (off 

SE end of Isla Tiburón).

Type Locality. Epiphytic on Sargassum from intertidal rock reef; Isla Turner (Turners), off SE end of Isla Tiburón, 

Islas de la Cintura, Gulf of California, Mexico.

Remarks. Described from the northern Gulf of California, Acrochaetium seriaspora is known only from the type 

collection. Dawson (1953a), in his original description of Kylinia 

seriaspora, noted that occasionally one or both of the pedicel 

cells became tetrasporangia. Primarily on the basis of the stellate chloroplast with single pyrenoid of K. seriaspora, a new 
4 4 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

combination is proposed. Further collections and DNA analyses 

are needed to test the specific and generic status of this taxon. 

Colaconematales

Colaconematales J. Harper et G. W. Saunders, 2002:471.

Algae are marine, composed of uniseriate, simple, or 

branched filaments. Cells contain one or more parietal plastids 

of various shapes, lobed, spiral, or irregular (but never stellate) 

and are with or without pyrenoids. 

Asexual reproduction is mainly by monosporangia. Life histories, where known, are biphasic or triphasic. Sexual phases are 

monoecious or dioecious. 

Currently a monotypic order, the Colaconematales is represented by the single family in the northern Gulf of California.

Colaconemataceae

Colaconemataceae J. Harper et G. W. Saunders, 2002:471.

The Colaconemataceae is apparently a monotypic family, 

with the characteristics of the order. 

Life histories, where known, are biphasic, involving two 

free-living isomorphic or slightly heteromorphic phases (rarely 

with a markedly distinct heteromorphic generations). Tetrasporophytes have a nonpersistent spore that develops a prostrate 

multicellular filamentous portion that gives rise to erect axes. 

Gametophytes of most species usually have a persistent spore 

that upon bipolar germination remains unicellular in a few species or in most develops a basal system of multicellular, prostrate 

filaments, from which the erect filaments arise. 

Remarks. Harper and Saunders (2002) noted that 

although the Colaconemataceae includes only one genus, it is 

likely that future research will add other genera to the family 

on the basis of their morphological, life history, and molecular 

features. The family is worldwide in distribution, and all of the 

species are exclusively marine, with the highest diversity in warm 

temperate to tropical seas. 

Currently, the family contains a single genus, Colaconema, 

which is known to occur in the Gulf of California.

Colaconema Batters

Colaconema Batters, 1896:8; Harper and Saunders, 2002:473.

Algae are microscopic to minute, usually epiphytic, and 

composed of simple to branched, uniseriate filaments. Branching 

of the erect axes may be irregular, secund, or opposite. Occasionally, the branches may have multicellular pseudohairs. Cells 

usually contain one parietal plastid, but a few species may have 

several lobed, parietal plastids. Chloroplasts are lobed, spiral, or 

irregular in shape and with or without pyrenoids. 

Monosporangia are the predominant mode of reproduction, found in both generations, and borne terminal on the 

axes or on short lateral branches. In many species of Colaconema, monosporangia are the only known mode of reproduction. Tetrasporangia are cruciately divided, single or in clusters, 

and are borne lateral or terminal on axes and lateral branches. 

Gametophytes, where known, are monoecious or dioecious. 

Carpogonia are sessile or pedicellate and lack a distinct carpogonial filament. The fertilized carpogonium divides transversely 

to produce short, filamentous gonimoblasts with terminal carposporangia. Spermatangia are borne in clusters of various 

shapes.

Remarks. Species of Colaconema are usually epiphytic, but some are also reported to be endo-epiphytic or epizoic 

or endo-epizoic. One species, Colaconema pectinatum (Kylin) 

J. T. Harper et G. W. Saunders (2002) is reported in the southern Gulf from La Paz (Huerta-Múzquiz and Mendoza-González, 

1985, as Acrochaetium pectinatum (Kylin) G. Hamel, 1927).

Nine species of Colaconema are now reported in the northern Gulf of California. 

KEY TO THE SPECIES OF COLACONEMA IN THE NORTHERN GULF OF CALIFORNIA

1a. Filaments exclusively endo-epiphytic (i.e., within and on outer cells) on species of Scinaia . . . . . . . . . . . . . . C. scinaiae

1b. Filaments growing on other algal species (not Scinaia) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Thalli less than 300 μm tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. punctatum

2b. Thalli more than 300 μm tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Erect filaments 8.0–12.0 μm in diameter; above a basal system of free filaments or of filaments coalescing into pseudoparenchymatous disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3b. Erect filaments narrower, 4.0–8.0 μm in diameter; basal attachment either a single cell or prostrate basal filaments (not 

coalescing or discoid) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4a. Filaments arising above by a basal pseudoparenchymatous disc of coalescing basal filaments or entangled mass of basal 

filaments; monosporangia in clusters of 3 or more on branched stalks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. daviesii

4b. Filaments attached by prostrate system of basal filaments (not coalescing); monosporangia single or in pairs (not in clusters) on unbranched stalks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. savianum

5a. Filaments attached by a single basal cell (either enlarged and conspicuous or similar in size to filament cells) . . . . . . . . 6

5b. Filaments attached by a basal system of basal filaments (not coalescing) creeping on host’s surface . . . . . . . . . . . . . . . 7

6a. Single basal cell enlarged (much larger in diameter than filament cells); filaments 4.0–6.0 μm in diameter . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. sinicola
NUMBER 96 • 4 5

6b. Single basal cell not enlarged or modified (same diameter and shape as filament cells); filaments 5.0–7.0 μm in diameter 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. hancockii

7a. Erect filaments 4.0–6.0 μm in diameter; upper portions usually branched; monosporangia terminal or sometimes lateral 

on short secund branchlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. pacificum

7b. Erect filaments mostly larger than 6 μm in diameter; upper portions unbranched or branched . . . . . . . . . . . . . . . . . . . 8

8a. Erect filaments 8.0–9.5 μm in diameter; upper portions branched or unbranched; attached by a basal disc of coalesced 

filaments, 1–2 cell layers thick; monosporangia terminal or lateral . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. variabile

8b. Erect filaments 6.0–8.0 μm in diameter; upper portions unbranched; attached by basal system of creeping filaments (not 

coalescing); monosporangia lateral on branchlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. tenuissimum

Colaconema daviesii (Dillwyn) Stegenga

Conferva daviesii Dillwyn, 1809:73, suppl. pl. F.

Colaconema daviesii (Dillwyn) Stegenga, 1985b:317, 320, fig. 20; Perestenko, 1996:47; Harper and Saunders, 2002:473; Serviere-Zaragoza et 

al., 2007:9. 

Ceramium daviesii (Dillwyn) C. Agardh, 1817:XXVII. 

Callithamnion daviesii (Dillwyn) Lyngbye, 1819:129, pl. 41: figs. B1–B3; 

Harvey, 1853:243.

Acrochaetium daviesii (Dillwyn) Nägeli, 1862:405, figs. 26, 27; Collins, 1906b:194; Papenfuss, 1945:308; Taylor, 1945:134; Papenfuss, 

1947a:435; Dawson, 1953a:28; Dawson et al., 1960b:15; Tokida, 

1960:92; Dawson, 1961b:403; Dawson and Neushul, 1966:175; 

Hollenberg and Abbott, 1966:41, fig. 14; Abbott and Hollenberg, 

1976:313, fig. 254; Silva, 1979:316; Stegenga and van Erp, 1979:443, 

figs. 11–14; Stewart and Stewart, 1984:142; González-González et 

al., 1996:166; Y.-P. Lee and Yoshida, 1997:162, fig. 1A–F; Yoshida, 

1998:463, fig. 3-4C.

Chantransia daviesii (Dillwyn) Thuret (in Le Jolis, 1863b:106.

Rhodochorton daviesii (Dillwyn) K. M. Drew, 1928:172; Setchell and 

Gardner, 1930:166; Smith, 1944:184; Nakamura, 1944:106, fig. 

5; I. K. Lee and Lee, 1974:41, fig. 4a–f; González-González et al., 

1996:264. 

Audouinella daviesii (Dillwyn) Woelkerling, 1971:28, figs. 7, 22; Woelkerling, 1973b:550, figs. 32–43; Dixon and Irvine, 1977b:90, fig. 22; Garbary, 1979a:952; 1979c:478; Garbary et al., 1983:19, fig. 6; Stegenga, 

1985b:317, fig. 20; Garbary, 1987:54; Y.-P. Lee, 1987:10, fig. 3A–E; 

Scagel et al., 1989:145; Ramírez and Santelices, 1991:179; Mateo-Cid 

and Mendoza-González, 1991:19; 1992:19; Mendoza-González and 

Mateo-Cid, 1992:16; Serviere-Zaragoza et al., 1993a:483; MateoCid and Mendoza-González, 1994b:38; Mendoza-González et al., 

1994:105; Y.-P. Lee and Yoshida, 1997:162, fig. 1A–F; Yoshida, 

1998:463, fig. 3, 4C; Y.-P. Lee, 2008:175, figs. A–D.

Algae often in tufts, usually epiphytic, or sometimes partially endo-epiphytic; erect, branched, uniseriate filaments, up to 

4 mm tall; arising from a base of creeping, entangled filaments, 

some of which may penetrate host cells. Erect filaments sparsely 

to more or less densely branched, mostly irregular, sometimes 

alternate or secund, up to several orders; filaments sometimes 

tapering upward, ending with multicellular, almost colorless extensions. Cell of axes and branches, 14–40 μm long by 9–15 μm 

in diameter (2–3 times longer than wide); cells of upper portions, 

narrower, 3–10 μm in diameter and 20–50 μm in length; cells of 

basal filaments 12–25 μm long and 6–14 μm in diameter. Plastids 

parietal, with a single prominent pyrenoid.

Monosporangia ovoid to ellipsoid, 12–14 μm long, 8–10 

μm wide; in clusters of 4–8 on short branchlets; borne on lowermost cells of branches. Sexual reproduction not yet observed 

in Gulf of California specimens; reported to be dioecious elsewhere. Carposporophyte with branched gonimoblast filaments 

with terminal carposporangia, 16–20 μm long by 8–10 μm in 

diameter. Spermatangia 2–4 μm in diameter, terminal or lateral 

in few to many, sometimes dense, clusters on branched stalks (see 

Womersley, 1994:51, fig. 9F,G). 

Habitat. Epiphytic or partially endo-epiphytic on 

Padina and various other algae; intertidal.

Distribution. Gulf of California: Puerto Peñasco; 

Punta Robinson (east of Puerto Libertad); Mazatlán, Sinaloa to 

Jalisco. Eastern Pacific: Alaska to Todos Santos (Baja California 

Sur); Isla Guadalupe; Isla Clarión (Islas Revillagigedo); Colima; 

Chile. Western Pacific: Russia; Korea; Japan.

Lectotype Locality. Probably north Wales, 

United Kingdom (Dixon and Irvine, 1977b; Silva et al., 1996b). 

Remarks. Colaconema daviesii is widely reported 

in temperate to tropical seas and now in the northern Gulf of 

California. Garbary (1987, as Audouinella daviesii) noted that 

many of the published accounts and records using this taxon 

name may be misidentified. 

Colaconema hancockii (E. Y. Dawson) J. N. Norris, comb. nov.

FIGURE 23A,B

Rhodochorton hancockii E. Y. Dawson, 1944a:255, pl. 41: figs. 4–6; 

González-González et al., 1996:264. 

Acrochaetium hancockii (E. Y. Dawson) Papenfuss, 1945:306; Dawson, 

1953a:25, pl. 12: fig. 2; 1961b:403; Huerta-Múzquiz and MendozaGonzález, 1985:48; Garbary, 1987:83.

Algae epiphytic, of cylindrical, narrow, erect filaments; attached to host alga by a single unmodified, rectangular basal cell. 

Erect filaments 0.5–1.5 mm long, simple or sparsely branched, up 

to 3 orders, becoming slightly attenuated upward; ultimate branchlets in more or less secund series on branches, very short, up to 4 μm 

in diameter, 3–4 μm long. Cells of filaments rectangular, 15–28 μm 

long, 5–7 μm in diameter; plastids not in original description, but 

noted to be “parietal” in the taxonomic key of Dawson (1953a:19).

Monospores ovoid, 10–11 μm long, 6–7 μm wide, borne on 

short lateral branchlets or sessile. Sexual reproduction unknown.

Habitat. Epiphytic on Gelidium; intertidal.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda; La Paz.
4 6 • SMITHSONIAN CONTRIBUTIONS TO BOTANY
NUMBER 96 • 4 7

Type Locality. On Gelidium, rocky shore along 

west side of Puerto Refugio, Isla Ángel de la Guarda, Islas de la 

Cintura, Gulf of California, Mexico.

Remarks. Described from the northern Gulf of California, Colaconema hancockii is a apparently known only from 

a few collections in the Gulf. It has also been reported in the 

Philippines (Silva et al., 1987). More Gulf collections for comparative molecular and life history culture studies will help to 

evaluate its taxonomic status.

Colaconema pacificum (Kylin) Woelkerling

FIGURE 23C–F

Acrochaetium pacificum Kylin, 1925:11, fig. 4g–i; Papenfuss, 1945:310; 

Doty, 1947:162; Papenfuss, 1947a:435; Dawson, 1953a:29; Dawson 

et al., 1960a:15; Tokida, 1960:92; Dawson, 1961b:404; Dawson et 

al., 1964:33, pl. 30: fig. B; Dawson and Neushul, 1966:175; Abbott 

and Hollenberg, 1976:315 [in part; excluding Rhodochorton variabile

and R. plumosa]; Pacheco-Ruíz and Aguilar-Rosas, 1984:76; Stewart 

and Stewart, 1984:142; Huerta-Múzquiz and Mendoza-González, 

1985:48; R. Aguilar-Rosas and Aguilar-Rosas, 1994:519; GonzálezGonzález et al., 1996:166; L. Aguilar-Rosas et al., 2002:234; MateoCid et al., 2006:55, 62.

Colaconema pacificum (Kylin) Woelkerling, 1971:9, 47, figs. 17A–D, 26A.

Rhodochorton pacificum (Kylin) K. M. Drew, 1928:169, pl. 38: fig. 25.

Chantransia pacifica (Kylin) Levring, 1941:631.

Audouinella pacifica (Kylin) Garbary, 1979a:490; Garbary et al., 1983:37; 

Garbary, 1987:131; Scagel et al., 1989:147; Ramirez and Santelices, 

1991:180.

Algae epiphytic; tufts of erect, uniseriate filaments, 4.0–6.0 

μm in diameter, up to 1 mm tall; sometimes unbranched or with 

a few, lateral branches, mostly in upper portion; laterals with 

numerous, short, secund, or sometimes opposite branchlets of 

1–3 cells in length; erect filaments arising from a prostrate system 

of creeping, branched, basal free filaments (not coalescing) on 

surface of host. Cells 2–3(–4) times longer than wide, (8–)10–

21(–28) μm in length, 4.0–7.0 μm in diameter; with parietal plastid and a large pyrenoid in distal potion of cell.

Monosporangia ellipsoidal, 8.0–10(–12) μm long, 6.0–9.0 

μm in diameter; terminal or sometimes lateral on short, secund 

branchlets. Sexual reproduction unknown.

Habitat. Epiphytic on Scinaia latifrons, Tricleocarpa, and probably other algae; low intertidal to shallow 

subtidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Ensenada de San Francisco (vicinity of 

San Carlos-Guaymas); Bahía de La Paz. Eastern Pacific: Alaska 

to Islas San Benito (off Isla Cedros), Baja California; Peru.

Type Locality. Syntype localities: Brown Island, 

Shaw Island, and Peavine Pass, vicinity of Friday Harbor, Washington (Kylin, 1925). Lectotype locality: Epizoic on Sertularia

(Hydrozoan); Brown Island, east-northeast of Friday Harbor, 

San Juan Island, San Juan County, Puget Sound, Washington, 

USA (Abbott and Hollenberg, 1976). 

Remarks. More collections are needed to elucidate 

the taxonomic status of the Gulf of California Colaconema pacificum and its phylogenetic relationship with type locality C. pacificum from the the northeastern Pacific.

Although recognizing that Colaconema pacificum and 

C. plumosum shared some features, Woelkerling (1971) separated the two by filament diameter, branch arrangement, and 

arrangement of sporangia. Drew (1928) and Nakamura (1944) 

had earlier noted that specimens of Rhodochorton plumosum 

K. M. Drew (1928) were not easy to separate from R. variabile K. M. Drew (1928), and later these two northeastern Pacific 

species were considered conspecifc with C. pacificum by Abbott 

and Hollenberg (1976, as Acrochaetium pacificum). Stegenga 

(1985b), in part supporting Abbott and Hollenberg (1976), observed that these two (as Acrochaetium plumosum and A. variabile) were likely conspecific but that A. pacificum was a species 

different from both of them on the basis of the distinctions as 

noted by Woelkerling (1971) and Garbary et al. (1983). Pueschel (1989, as Audouinella species) supported separation of 

C. pacificum and C. plumosum on the basis of ultrastructural 

evidence of different outer caps in the pit plugs and suggested 

 FIGURE 23. (Opposite) Species of Colaconema. A, B. Colaconema hancockii: A. Habit. B. Basal portion showing unenlarged attachment cell 

on host (type collection) (A, B after Dawson, 1944a, pl. 41, figs. 4, 6, as Rhodochorton hancockii). C–F. Colaconema pacificum: C–E. Erect filaments with monospores (after Kylin, 1925: figs. 4g–i, as Acrochaetium pacificum). F. Base of a group of erect filaments and cells of the creeping 

filaments, showing the parietal chloroplasts (after Drew, 1928: pl. 38, fig. 25, as Rhodochorton pacificum). G. Colaconema punctatum: Erect 

filaments with numerous short, secund branchlets, attached superficially to host by a slightly enlarged basal cell (after Dawson, 1953a, pl. 2, 

fig. 1, as Acrochaetium punctatum). H, I. Colaconema variabile: H. Multistromatic layer of horizontally growing filaments of epiphyte on host. 

I. Secund arrangement of branchlets on erect filament (H, I after Drew, 1928: pl. 39, figs. 30, 31, as Rhodochorton variabile). J. Colaconema 

sinicola: Habit of type collection showing enlarged basal cell embedded in host and filaments bearing monosporangia (after Dawson, 1944a, 

pl. 41, fig. 1, as Rhodochorton sinicola). K. Colaconema tenuissimum: Part of two erect filaments enlarged (after Drew, 1928: pl. 38, fig. 27, as 

Rhodochorton tenuissimum). L, M. Colaconema scinaiae: L. Detail of an upright filament bearing a monospore. M. Habit of creeping filaments 

endophytic among utricles and cortical cells of host, Scinaia (L, M after Dawson, 1949b: pl. 2, figs. 11, 12, as Acrochaetium scinaiae).
4 8 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

that C. pacificum may have affinities with C. variabile (see also 

Remarks under Colaconema variabile). 

Colaconema punctatum (E. Y. Dawson) J. N. Norris, comb. nov.

FIGURE 23G

Acrochaetium punctatum E. Y. Dawson, 1953a:25, pl. 2: fig. 1; 1961b:404; 

Garbary, 1987:145; Espinoza-Avalos, 1993:332; González-González et 

al., 1996:167.

Thalli erect and epiphytic; of several curved filaments, 100–

300 μm tall; attached to algal host by a single, slightly enlarged, 

basal cell, 9–12 μm in diameter. Filaments 6–7 μm in diameter, 

with numerous short, secund branchlets on convex side. Cells 

12–14 μm long, 6–7 μm in diameter, with a parietal chloroplast 

and single pyrenoid.

Asexual reproduction unknown. Female gametophytes not 

found. Spermatangia borne on short, secund lateral branchlets.

Habitat. Epiphytic on leaf-like blades of Sargassum; 

intertidal.

Distribution. Gulf of California: Puerto Peñasco; 

Bahía Bocochibampo.

Type Locality. Southern shore, Bahía Bocochibampo, Sonora, Gulf of California, Mexico.

Remarks. Generally considered a Gulf of California 

endemic, Colaconema punctatum has also been recorded from 

Michoacán (Stout and Dreckmann, 1993, as “Acrochaetium 

punctatum”). 

Colaconema savianum (Meneghini) R. Nielsen

Callithamnion savianum Meneghini, 1840a:[3]; Meneghini, 1840b:511; J. 

Agardh, 1842:74; Kützing, 1849:641; J. Agardh, 1851:14. 

Colaconema savianum (Meneghini) R. Nielsen, 1994:715; Nielsen et al., 

1995:5. 

Colaconema savianum (Meneghini) Perestenko, 1996:47. 

Acrochaetium savianum (Meneghini) Nägeli, 1862:405, 414; Papenfuss, 

1945:311; Papenfuss, 1947a:435; L. Aguilar-Rosas et al., 2000:130, 

137; Mateo-Cid et al., 2000:63. 

Chantransia saviana (Meneghini) Ardissone, 1883:276.

Audouinella saviana (Meneghini) Woelkerling, 1973b:560, figs. 56–60; 

Garbary, 1979c:479; 1987:163; Schneider and Searles, 1991:207, figs. 

247–249; Mendoza-González and Mateo-Cid, 1996b:65, 83, pl. 2: 

figs. 7–9; Mateo-Cid and Mendoza-González, 1997:56, pl. 1: figs. 3, 4; 

Dreckmann et al., 2006:140,154.

Algae epiphytic or partly endo-epiphytic; up to 4 mm in 

length; attached by a prostrate basal system of short, simple to 

branched filaments that remain free or partly coalesce into an 

irregularly shaped disc (initial spore not always evident). Erect 

filaments mostly irregularly branched or sometimes alternate to 

secund. Cells in axes and branches, 20–60 μm long, 8–12(–14) 

μm in diameter; cells narrower in ultimate branchlets, 4–6 μm 

in diameter. Cells with a single parietal plastid and 1 pyrenoid.

Reproduction not reported in Gulf of California specimens. 

The following description is as reported for this species elsewhere (Woelkerling, 1973b; Schneider, 1983). Monosporangia 

ovoid to ellipsoid, single or in pairs, either sessile or on 1- to 

3-celled pedicels; 18–27 μm long by 10–15 μm in diameter. Tetrasporangia cruciate, 26–34 μm long by 17–24 μm in diameter. 

Carpogonia singular, near base of branches in lower portion of 

thallus; carpospores, 18–21 μm long by 9–13 μm in diameter. 

Spermatangia sparse, on short branchlets near base of branches. 

Habitat. Epiphytic on Ulva intestinalis, Chaetomorpha, Bryopsis, and Sargassum and epizoic on Aglaophenia (Hydrozoa); intertidal to shallow subtidal.

Distribution. Gulf of California: Punta Pelícano, 

Puerto Peñasco; Puertecitos; Punta Arenas. Eastern Pacific: Oaxaca to Chiapas. Western Pacific: Russia.

Type Locality. Epiphytic on Zostera; Genoa, Ligurian Sea, province of Genoa, Italy. 

Remarks. A collection, epizoic on the feather-like 

hydrozoan Aglaophenia from the rocky low intertidal on the 

southwest shore of Punta Pelícano, Puerto Peñasco, is tentatively 

referred to Colaconema savianum (JN-5058, US Alg. Coll. microscope slide 4263). It has numerous monosporangia, as well as 

the empty spore walls left after their release, and is a northern 

extension of the Gulf distribution.

A Mediterranean species, Colaconema savianum has been 

reported from the coastal eastern United States (Woelkerling, 

1973b; Schneider and Searles, 1991, as Audouinella saviana), 

western Atlantic (Taylor, 1960; Wynne, 2005), Europe (Guiry 

and Guiry, 2010), and northwestern Pacific (Perestenko, 1996). 

It was reported in the northern Gulf of California by AguilarRosas et al. (2000, as Acrochaetium savianum). 

There are two taxonomic combinations of Colaconema savianum, and some confusion as to which is the earliest valid publication. Regarding the publication of Nielsen (1994), the index 

to the Nordic Journal of Botany (1994, volume 14) gives the 

“effective date of publication” of issue number 6 as “28 Dec. 

1994.” The back page of the book by Perestenko (“1994”; in 

Russian) notes date accepted for publication as “29.12.92,” and 

that the “date authorized for printing” was “29.12.94” (indicating it was published on or after that date). Although they may 

have been published one day apart, the Perestenko work was 

apparently published much later, in 1996.

Colaconema scinaiae (E. Y. Dawson) J. N. Norris, comb. nov.

FIGURE 23L,M

Acrochaetium scinaiae E. Y. Dawson, 1949b:3, pl. 2: figs. 11, 12; 1953a:26; 

1961b:404; Garbary, 1987:166; Kajimura, 1987a:131, figs. 1–8; Stout 

and Dreckmann, 1993:9; González-González et al., 1996:167; AnayaReyna and Riosmena-Rodríguez, 1996:864, tbl. 1; Yoshida, 1998:458; 

CONANP, 2002:136; Riosmena-Rodríguez et al., 2005b:102.

Acrochaetium desmarestiae sensu Abbott and Hollenberg, 1976:314 [in part; 

only A. scinaiae; non Acrochaetium desmarestiae Kylin, 1925:10].

Algae minute; in patches, 1–2(–3) mm in diameter; some 

entirely epiphytic, others partially endo-epiphytic; attached by 

creeping filaments on and between utricles and cortical cells 

of their host, species of Scinaia. Endophytic filaments cylindrical; irregular in shape, of variously curved, narrow elongate cells among the cortical cells of alga host. Erect filaments, 
NUMBER 96 • 4 9

(18–)30–100 μm tall and 3.5–5.0 μm in diameter, of (2–)5–10 

cells; unbranched or irregularly and sparsely branched; apical 

cells rounded. A few cells of the filaments may (sparsely) bear 

long, simple hairs. Cells mostly 5.0–20 μm long; with a parietal, 

band-shaped plastid. 

Monosporangia terminal on 1- to 2-celled pedicel; 10–15 μm 

long by 5–10 μm in diameter. Sexual reproduction not known. 

Habitat. Endo-epiphytic on Scinaia johnstonii, 

S. latifrons, or S. confusa; low intertidal to 9 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to Ensenada de San Francisco; Punta Los Frailes. Eastern Pacific: 

Santa Barbara Island (California Channel Islands); Michoacán. 

Western Pacific: Oki Islands, Japan. 

Type Locality. Epiphytic on Scinaia articulata

Setchell; dredged to 30–41 m depths, off north end of Santa 

Barbara Island (33°30′58′′N, 119°50′W), California Channel 

Islands, southern California, USA.

Remarks. The distribution range of Colaconema 

scinaiae is extended to the northern Gulf by the collection from 

Puerto Peñasco (endo-epiphytic on Scinaia confusa (JN-5024b, 

US Alg. Coll. microscope slide 4247). Dawson (1953a) noted 

the species probably occurs throughout the range of the species 

of Scinaia in Pacific Mexico. Although noting its resemblance 

to A. desmarestiae Kylin (1925; =Colaconema desmarestiae

(Kylin) P. W. Gabrielson (in Gabrielson et al., 2004:95), Dawson (1949b, as A. scinaiae) stated C. scinaiae differed in generally forming smaller colonies on the host alga and in having 

much longer, distinctly attenuated, filaments of 6–10 cells, up 

to 100 μm in length, with some of the filaments possibly also 

having short branchlets and some of the cells possibly also bearing multicellular hairs. Although Abbott and Hollenberg (1976) 

considered C. scinaiae to be conspecific with A. desmarestiae,

Kajimura (1987a, as A. scinaiae) retained it as a distinct taxon. 

I too recognize them as a separate species, and primarily on 

the basis of their chloroplast characteristics (see also Dawson, 

1949b: fig. 11), I propose the new combination. Culture, cytological, and DNA studies on Gulf C. scinaiae and comparison 

to type locality material will allow testing of their taxonomic 

status.

Colaconema sinicola (E. Y. Dawson) J. N. Norris, comb. nov.

FIGURE 23J

Rhodochorton sinicola E. Y. Dawson, 1944a:256, pl. 41: figs. 1, 2; GonzálezGonzález et al., 1996:264. 

Acrochaetium sinicolum (E. Y. Dawson) Papenfuss, 1945:317; Dawson, 

1953a:26, pl. 12: fig. 1; 1961b:404; Garbary, 1987:173; Dreckmann 

et al., 1990:27, pl. 4: fig. 3; Espinoza-Avalos, 1993:332; GonzálezGonzález et al., 1996:167, 381.

Algae epiphytic; composed of 1 to several erect filaments, up 

to 500 μm tall; branched abundantly basally; branching sparse 

above, but with longer branches; branches not markedly attenuated; arising from an enlarged basal cell embedded between cells 

of alga host. Cells 12–33.6 μm long, 4.0–5.6 μm wide, with a 

parietal plastid.

Monosporangia ovoid, 11–14 μm long, borne terminally 

on, usually 2-celled, lateral secund branchlets. Carposporangia 

unknown. Spermatangia borne in clusters terminally on short 

lateral branchlets.

Habitat. Epiphytic on Dictyota; intertidal to shallow subtidal.

Distribution. Gulf of California: Isla Turner. Eastern Pacific: Michoacán.

Type Locality. Isla Turner (Turners), off SE end of 

Isla Tiburón, Islas de la Cintura, Gulf of California, Mexico. 

Colaconema tenuissimum (Collins) Woelkerling

FIGURE 23K

Chantransia virgatula (Harvey) Bornet f. tenuissima Collins in Collins, 

Holden and Setchell, 1900: Exsiccate P.B.-A. No. 714.

Colaconema tenuissimum (Collins) Woelkerling, 1971:9, 51, fig. 21.

Acrochaetium virgatulum (Harvey) Bornet f. tenuissimum (Collins) Collins, 

1906b:194.

Acrochaetium tenuissimum (Collins) Papenfuss, 1945:319; Dawson, 1961b: 

404; Abbott and Hollenberg, 1976:319, fig. 262; Stegenga, 1985b:305, 

fig. 12. 

Rhodochorton tenuissimum (Collins) K. M. Drew, 1928:170, pl. 38: figs. 

26, 27. 

Chantransia tenuissima (Collins) Kylin, 1941:5, figs. 1e,f. 

Audouinella tenuissima (Collins) Garbary, 1979c:479, 490; 1987:182. 

Chromastrum tenuissimum (Collins) Stegenga et Kemperman, 1983:72.

Algae epiphytic, erect filaments unbranched or sparingly 

and irregularly branched, attached by a prostrate basal system of 

creeping filaments. Branches tapering slightly toward the apices. 

Cells cylindrical, 6–8 μm in diameter by 25–48 μm long, with a 

single parietal plastid and 1 pyrenoid.

Monosporangia sessile, ovoid, 12–15 μm in diameter by 

21–23.5 μm long, scattered along main axis and branches. Other 

reproductive structures unknown.

Habitat. Epiphytic on Ceramium caudatum, which 

was growing on Dictyopteris; mid to low intertidal. 

Distribution. Gulf of California: Punta Pelícano, 

vicinity of Puerto Peñasco. Eastern Pacific: San Pedro, southern 

California. 

Type Locality. Epiphytic on Phyllospadix; San 

Pedro harbor entrance, San Pedro, Los Angeles County, southern 

California, USA.

Remarks. A single collection from the upper Gulf 

seems closest to Colaconema tenuissimum. New to the Gulf, 

C. tenuissimum was originally only known from southern California (Kylin, 1941; Abbott and Hollenberg, 1976) and has been 

subsequently reported in Australia (Woelkerling, 1971), Atlantic 

Costa Rica (Stegenga and Kemperman, 1983), and South Africa 

(Stegenga, 1985b). 

Woelkerling (1973b), studying specimens of Colaconema 

tenuissimum from the northeastern United States, considered it 

to be a synonym of Colaconema secundatum (Lyngbye) Woelkerling (1973a). However, Stegenga and Kemperman (1983, as 

Chromastrum tenuissimum (Collins) Stegenga et Kemperman) 
5 0 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

and Stegenga (1985b) did not follow Woelkering (1973b) and 

commented on their distinction, primarily the larger monosporangia of C. tenuissimum, and its very different initial development. The basal portion of C. tenuissimum has a conspicuous 

angular, 3-celled septate spore and short prostrate filaments, 

and A. secundatum has a discoid base in which the initial spore 

divides into a 4- to 6-celled pattern. Herein these two are considered separate until life history studies and molecular comparisons have been undertaken on Gulf of California specimens.

Colaconema variabile (K. M. Drew) J. N. Norris, comb. nov.

FIGURE 23H,I

Rhodochorton variabile K. M. Drew, 1928:174, pl. 38: fig. 28, pl. 39: figs. 

30, 31; Garbary, 1987:138; González-González et al., 1996:264. 

Acrochaetium variabile (K. M. Drew) G. M. Smith, 1944:179; Dawson, 1949c:222; 1953a:29; 1954a:4; 1961b:405; 1962d:394; 

Dawson et al., 1964:37, pl. 30: fig. A; Stewart and Stewart, 

1984:142; Ramírez and Santelices, 1991:179; González-González 

et al., 1996:168, 381; Serviere-Zaragoza et al., 2007:9; FernándezGarcía et al., 2011:59.

Audouinella variabilis (K. M. Drew) Garbary in Garbary et al., 1980a:322; 

Garbary, 1987:138, 192.

Audouinella plumosa var. variabilis (K. M. Drew) Garbary, G. I. Hansen et 

Scagel, 1983:42; Garbary, 1987:138; Scagel et al., 1989:148.

Colaconema plumosum (K. M. Drew) Woelkerling var. variabile (K. M. 

Drew) P. W. Gabrielson in Gabrielson et al., 2000:40.

Acrochaetium pacificum sensu Abbott and Hollenberg, 1976:315 [in part; 

only in reference to A. variable]; Stewart and Stewart, 1984:142 [non 

Acrochaetium pacificum Kylin, 1925:11, which is now Colaconema 

pacificum (Kylin) Woelkerling, 1971:9].

Algae minute, of several erect filaments, 0.5–1.0 mm tall; 

arising above a basal system of prostrate filaments that have 

coalesced to form a layer 1–2 cells thick. Erect filaments, 8.0–

9.5 μm in diameter; lower portions unbranched or with long 

branches; upper portions with short, unbranched or branched, 

branchlets in secund series. Cells elongated, 2–3(–4) times longer 

than wide, 16–29(–38) μm in length by 8–9.5 μm in diameter; 

with a parietal plastid and a single large pyrenoid.

Monosporangia terminal or lateral on secund branchlets; 

monosporangia ovoid, 5.0–7.0 μm wide. 

Habitat. Epiphytic on various algae; low intertidal.

Distribution. Gulf of California: Mazatlán. Eastern Pacific: British Columbia to Punta Baja, Baja California; Isla 

Guadalupe; Isla San Martín; Isla San Benedicto (Islas Revillagigedo); Nicaragua; Peru; Chile. 

Type Locality. Epiphytic on Laminaria andersonii; 

Cypress Point, Monterey County, central California, USA. 

Remarks. Difficulties in separating Colaconema 

variabile from C. plumosa were discussed by Drew (1928), Nakamura, (1944), Woelkerling (1971), and Stegenga (1985b) (see 

also Remarks under C. pacificum). Although Rhodochorton 

variabile has been recognized at a varietal rank, first as Auduoinella plumosa var. variabile (Garbary et al., 1983) and later 

as C. plumosa var. variabile P. W. Gabrielson (in Gabrielson et 

al., 2000), Pueschel (1989, as a species of Audouinella) provided 

ultrastructural data of pit plugs that C. plumosa and C. variabile 

were not related, and that C. variabile showed possible affinities 

with C. pacificum. 

Dawson (1953a, as Acrochaetium variabile) observed that 

Pacific Mexico C. variabile were comparatively slender forms of 

the species and mostly unbranched in lower portions. Although 

thus far known only in the southern Gulf, C. variabile is included 

here to call attention to the fact that the Gulf material is in need 

of critical study.

Nemaliales

Nemaliales F. Schmitz, 1892:17 [as “Nemalionales”; see Nicolson and Norris, 1983:286].

Members of the Nemaliales include algae that are terete, 

compressed or flattened thalli, that are mostly erect, or some 

may be decumbent, and subdichotomously or variously to irregularly branched. Members have a triphasic life history with 

isomorphic, dimorphic, or heteromorphic phases. Gametophytic 

thalli are multiaxial in structure, with a central medulla of diffuse to compact filaments that bear anticlinal filaments that ultimately form the cortex. The Nemaliales presently includes three 

families, the Liagoraceae, Galaxauraceae, and Scinaiaceae (Huisman, 2006). In some families the cortex is composed of loose 

filaments; in others the filaments may be more compact, laterally 

adjoined, or with cells fused to form a pseudoparenchymatous 

cortex. Members of some families are noncalcified (i.e., Scinaiaceae), and other members are calcified with calcium carbonate in 

the aragonite form of the mineral (e.g., Galaxauraceae and most 

of the Liagoraceae). Some taxa are gelatinous or mucilaginous, 

with external mucilage (some Liagoraceae) and mucilage-filled 

axes contained by cortical layers (Scinaiaceae), whereas members 

of the Galaxauraceae are not mucilaginous. Cells are uninucleate 

and have one or more plastids with pyrenoids. Secondary cell 

fusions occur in some taxa, but secondary pit connections are 

absent in all members. 

Life histories, where known, are triphasic, involving haploid, monoecious or dioecious gametophytes, a postfertilization 

diploid carposporophyte that develops on or within the female 

gametophyte, and diploid tetrasporophytes. Tetrasporophytic 

thalli are (1) isomorphic (similar morphology to the gametophytes) or almost isomorphic (similar external morphology but 

with differences in cortical structure; e.g., Howe, 1917, 1918), 

(2) dimorphic (similar in size but with some differences in external morphology and cortical anatomy ), or (3) markedly heteromorphic, with relatively larger gametophytes and smaller to 

minute tetrasporophytes of a different form, either uniseriate filaments or prostrate crusts (e.g., Feldmann and Feldmann, 1943; 

von Stosch, 1965; Ramus, 1969; Couté, 1971, 1976; Delépine 

et al., 1979; Magruder, 1984; Guiry, 1990a; Brodie and Norris, 

1996). Tetrasporangia are typically cruciately divided.
NUMBER 96 • 5 1

Sexual reproduction in the Nemaliales is characterized by 

the absence of an auxiliary cell; the gonimoblast develops directly from the fertilized carpogonium. In the Galaxauraceae 

and Scinaiaceae, the carpogonial branches are three-celled, 

composed of a basal cell, a hypogynous cell, and a terminal carpogonium, with the hypogynous cell bearing nutritive branches 

(or cells). The gonimoblasts can be compact, and the carposporophyte has a surrounding distinct pericarp and ostiole. In 

the Liagoraceae, the carpogonial branch is extremely variable, 

from (2–)3 to many celled, and the hypogynous cell is usually 

naked. The gonimoblasts can be compact or diffuse, and the 

carposporophyte can be naked or with a loose involucre of filaments. Spermatangia of the Nemaliales are borne superficially 

on the thallus surface or in clusters on cortical filaments or in 

cavities. 

Remarks. Although the order has often been referred 

to as the “Nemalionales” (e.g., Kylin, 1956), Nicolson and Norris (1983) pointed out that the correct name is the Nemaliales. 

All three families of the Nemaliales are represented in the 

northern Gulf of California.

KEY TO THE FAMILIES OF NEMALIALES IN THE NORTHERN GULF OF CALIFORNIA

1a. Algae noncalcified; gametophytes terete or compressed to somewhat flattened; life histories heteromorphic, tetrasporophytes either crusts or uniseriate filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Scinaiaceae

1b. Thalli lightly to heavily calcified; gametophytes terete, compressed, or flattened; life histories isomorphic, dimorphic, or 

heteromorphic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Axes terete to compressed (not flattened); cortex of loosely arranged filaments, easily disassociated from each other; spermatangia are borne in clusters at or near the tips of assimilatory filaments or in whorls on midcortical cells; life histories 

heteromorphic, tetrasporophytes uniseriate filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Liagoraceae

2b. Axes terete to distinctly flattened; cortex not easily disassociated, cortical filaments tightly packed, somewhat laterally coherent or with fusions between some adjacent inner cortical cells; spermatangia in conceptacle-like cavities; life histories 

either isomorphic, dimorphic, or heteromorphic (tetrasporophytes either uniseriate filaments or crusts) . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Galaxauraceae

Galaxauraceae

Galaxauraceae P. G. Parkinson, 1983:606.

Chaetangiaceae Kützing, 1843:389, 391 [as “Chaetangieae”]; Silva, 1980:81 

[see Parkinson, 1983].

Gametophytes of this family are erect and calcified, with 

terete, compressed, or flattened axes. Most members are dichotomously to subdichotomously, or rarely irregularly, branched. Anatomically, all are multiaxial, with an axial core of longitudinal 

medullary filaments, from which subdichotomously branched 

filaments grow anticlinally outward and ultimately form the cortex. The cortex either remains filamentous or develops a pseudoparenchymatous layer of laterally coherent cells, with some 

having fusions between adjacent cortical cells. The surface is partially to entirely smooth or has spinulose cells or short to long 

pigmented assimilatory filaments (“hair-like”) extending from 

the cortex of various species. 

Life histories involve tetrasporophytes and gametophytes 

that are (1) isomorphic (i.e., externally similar in habit, differing 

only in cortical structure), (2) dimorphic (i.e., similar in size but 

differing in both habit and cortical structure), or (3) heteromorphic with macroscopic gametophytes and either a much smaller 

filamentous or crustose tetrasporophyte. Tetrasporophytes, where 

known, produce cruciately divided tetrasporangia. The carpogonial branch of the female gametophyte is borne on inner cells of 

a cortical filament and is three-celled with nutritive cells or filaments issued from the hypogynous cell and sterile filaments derived from the basal cell. Gonimoblast filaments develop directly 

from the zygote. At maturity, the carposporophyte has produced 

branched gonimoblast filaments with terminal carposporangia, 

either solitary or in chains, within a conceptacle formed from filaments developed from the basal cell of the carpogonial branch or 

from gonimoblast filaments. Cystocarps are immersed in the axes 

(outer medulla) and are ostiolate. Spermatangia are scattered 

over the outer cortical cell layer or on hypodermal cells (inner 

cortical cells) or within conceptacle-like cavities. 

Remarks. Dimorphism of life history phases (gametophytes and tetrasporophytes) was proposed for species of 

Galaxaura by Howe over 98 years ago (1916, 1918); however, a 

single entity may have received two different species names, one 

for the tetrasporophyte and another for the gametophyte, because of their morphological dissimilarity. This has complicated 

Galaxaura taxonomy (Chou, 1945; Zhou and Chen, 1983) and 

subsequently resulted in many synonyms (e.g., Papenfuss et al., 

1982). The correlation of the presumed alternate generations 

cannot be resolved solely by studying herbarium material. Direct 

seasonal observations of field populations may reveal associations of asexual and sexual species, which may be involved in 

a single life cycle. These associations could then be tested in the 

laboratory with life history studies and verified by phylogenetic 

analyses using instructive genetic markers to correlate haploid 

and diploid phases to the correct species names (e.g., Huisman et 

al., 2004c; Kurihara et al., 2005). 

Currently, there are four genera recognized in the Galaxauraceae, three of which are recorded in the northern Gulf of 

California. 
5 2 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

KEY TO THE GENERA OF GALAXAURACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Axes flattened, nonsegmented (in Gulf species); gametophytes and sporophytes macroscopically isomorphic, differing 

mainly in cortical anatomy; surfaces of both gametophytes and sporophyte glabrous (cortex without extended assimilatory filaments, “hairs”) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dichotomaria

1b. Axes terete, nonsegmented (some may appear “segmented” because of breaks in calcification, usually at branching 

points); gametophytes and sporophytes either (1) dimorphic (differing in both habit and cortical anatomy) only gametophyte surface glabrous (without “hairs”) and sporophytes with hirsute (“hairy”) surface (cortex with extended assimilatory filaments) or (2) phases markedly heteromorphic, sporophytes are branched uniseriate filaments . . . . . . . . . . . . . 2

2a. Gametophytes and sporophytes heteromorphic; gametophytes surface glabrous (smooth), without extended assimilatory 

filaments; cortical cells not firmly laterally attached to each other (fusions lacking); sporophytes uniseriate, branched 

filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tricleocarpa

2b. Gametophytes and sporophytes dimorphic, differing in habit and cortical cell structure; sporophyte surface entirely or 

partially covered in extended assimilatory filaments; gametophytes surface mostly glabrous; inner cortex of firmly, laterally cohering cells (fused in some species) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Galaxaura

KEY TO THE SPECIES OF DICHOTOMARIA, GALAXAURA, AND TRICLEOCARPA 

IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli distinctly flattened or strongly compressed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Thalli terete throughout or partially terete with upper portions slightly compressed . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2a. Lateral margins thicken and raised on drying; cortex of sporophytes with stalk-like cells bearing subspherical outer 

cortical cells that occasionally have an apiculate apex (more common near margins); cortex of gametophytes with outer 

spinulose cells mostly along axes margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dichotomaria marginata

2b. Lateral margins usually not raised on drying; cortex of sporophytes with stalk-like cells bearing ellipsoid or slightly flattened 

outermost cortical cells, cell apices not apiculate; cortex of gametophytes with outer spinulose cells covering thallus surface

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dichotomaria spathulata

3a. Thallus surface partially or entirely hirsute (hairy); cortical layer with some extending assimilatory filaments (not completely smooth) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3b. Thallus surface glabrous throughout (without hairs/assimilatory filaments) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4a. Thallus mostly terete (upper portions may be slightly compressed); surface either glabrous, often annulate (calcification 

interrupted by clear transverse bands), or with lower portions hairy and upper portions with occasional assimilatory filaments on outer cortical cells; some fusions present between adjacent inner cortical cells (gametophyte) . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Galaxaura rugosa (in part)

4b. Thallus terete; surface not smooth, hirsute (hairy), with both long and short assimilatory filaments; adjacent inner cortical cells not fused . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5a. Cortex of tumid basal cells, 50–60 μm long, 30–40 μm in diameter, that bear assimilatory filaments that are either (a) 

short, of 2 or 3 subglobose cells, or (b) long filaments of elongated cells, 28–54 μm long, 14–16 μm in diameter basally, 

slightly wider upward, 16–18 μm in diameter (sporophyte) . . . . . . . . . . . . . . . . . . . . . . . . . Galaxaura rugosa (in part)

5b. Cortex of tumid basal cells, 40–65 μm long by 20–40 in diameter, that bear assimilatory filaments that are either (a) 

short, of 2(–3) cells and a subglobose terminal cell, 20–32 μm in diameter), or (b) short to long filaments, 0.8–1.2 mm 

in length, of elongated cells, 18–60 μm long, 12–15 μm in diameter basally, widening upward to 18–20 μm in diameter 

(sporophyte) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Galaxaura ramulosa

6a. Branches narrow, 0.5–1.5 mm in diameter; gonimoblast filaments lining all sides of pericarp, mixed with numerous, welldeveloped paraphyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tricleocarpa cylindrica

6b. Branches broader, 1.5–2.0 mm in diameter; gonimoblast filaments growing laterally only along base of pericarp, mixed 

with poorly developed paraphyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tricleocarpa fragilis

Dichotomaria Lamarck

Dichotomaria Lamarck, 1816:143; J. Agardh, 1876:529.

Alysium C. Agardh, 1823:433; Wynne, 2008:323, figs.1–3.

Algae are calcified, terete or flattened and subdichotomously branched thalli with axes that are smooth, or some have 

basal portions that are hirsute (hairy). Branches sometimes have 

proliferations, with or without distinct segments depending on 

the species. Medulla is filamentous. Gametophytes and tetrasporophytes are isomorphic, and although these life history phases 

are similar in habit, their cortical anatomy differs. Gametophytes 

have a closely packed cortex, usually of 3 layers: inner 2 cortical 
NUMBER 96 • 5 3

layers of large, nearly hyaline cells that frequently fuse laterally, 

and an outer cortical layer of smaller pigmented cells. Carpogonial branches are borne in place of a normal vegetative filament. 

The carpogonial branch is 3-celled, composed of a basal cell, 

a hypogynous cell, and carpogonium. Before fertilization the 

hypogynous cell has 3–4 nutritive branches, and the basal cell 

has up to 4(–5) small-celled sterile filaments (Huisman, 2006). 

After fertilization, gonimoblast initials develop from the carpogonium and radiate outward. Cystocarps have a central fusion 

cell. Surrounding the carposporophyte is a pericarp formed by 

both gonimoblast filaments and involucral filaments derived 

from the basal cell of the carpogonial branch. Carposporangia 

are terminal on gonimoblast filaments that project toward center of the cystocarp cavity; pericarp filaments never extend into 

the cystocarp cavity. Spermatangia are borne in conceptacle-like 

cavities.

Sporophytes have a cortex of 3–6 layers: inner 1–3 cortical 

layers of large hyaline cells and an outermost layer of pigmented 

ellipsoid, subglobose, or wedge-shaped cells borne on loosely 

spaced stalk-like cells. Tetrasporangia are cruciately divided, 

borne laterally on stalk cells of cortex or terminally from outermost cortical cells. 

Remarks. Huisman et al. (2004b), on the basis of 

genetic, life history, and morphological characters, resurrected 

the genus Dichotomaria and transferred some Galaxaura species 

to the genus. 

Two species of Dichotomaria, both flattened, occur in the 

northern Gulf of California.

KEY TO THE SPECIES OF DICHOTOMARIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Axes flattened, with thickened margins (raised on drying); Gulf gametophytes surface mostly smooth, but with spinulose 

cells (often dense) protruding along axes margins; sporophyte (not known in Gulf) cortex with pairs of subspherical cells 

on stalk cells; subspherical cells occasionally with apiculate apices, notably along axes margins . . . . . . . . D. marginata

1b. Axes flattened, margins even or only slightly raised (on drying); gametophytes (not known in Gulf) with spinulose cells 

over entire thallus surface; Gulf sporophytes with stalk cells bearing subspherical, nonapiculate cells that form outermost 

cortical layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. spathulata

Dichotomaria marginata (J. Ellis et Solander) Lamarck

FIGURE 24

Corallina marginata J. Ellis et Solander, 1786:115, pl. 22: fig. 6 [fig. 6 selected 

as lectotype by Papenfuss et al., 1982:411]. 

Dichotomaria marginata (J. Ellis et Solander) Lamarck, 1816:146; Huisman 

et al., 2004b:230; Huisman et al., 2004c:344, fig. 10; Huisman and 

Kurihara, 2006:17, figs. 5A,B, 6A; Fernández-García et al., 2011:61; 

Wiriyadamrikul et al., 2014:34, fig. 6A–I.

Galaxaura marginata (J. Ellis et Solander) J. V. Lamouroux, 1816:264; 

Dawson, 1944a:258; 1961b:407; Papenfuss et al., 1982:411, figs. 7–9, 

24, 36–37; Huisman and Borowitzka, 1990:157, figs. 14–27; Dreckmann, 1991:33; González-González et al., 1996:311; Abbott, 1999:67, 

fig. 7G,H; Mateo-Cid et al., 2000:63; Cruz-Ayala et al., 2001:191; 

CONANP, 2002:141; Y.-P. Lee, 2008:218, figs. A–C; Bernecker, 

2009:CD-Rom p. 61. 

Zanardinia marginata (J. Ellis et Solander) J. Agardh, 1876:534. 

Galaxaura veprecula Kjellman, 1900:80, pl. 16, figs. 17–33, pl. 20: fig. 20; 

Tanaka, 1936:169, figs. 36, 37, pl. 43: fig. 1; Taylor, 1945:143; Chou, 

1947:16, pl. 6: figs. 1–8, pl. 12: fig. 2; Dawson, 1953a:53, pl. 18: fig. 

2; 1957c:14; 1959a:20; 1961b:407; 1962b:229; Zhou and Chen, 

1983:84, pl. 2: figs. 9, 10; Huerta-Múzquiz and Mendoza-González, 

1985:48; González-González et al., 1996:203: Riosmena-Rodríguez et 

al., 1998:28.

Galaxaura ventricosa sensu Taylor, 1945:143 [in part; Nayarit specimen]; 

Chou, 1947:18, pl.6: figs. 9–12, pl. 12: fig.2; Zhou and Chen, 1983:85, 

pl. 1: fig. 11; Serviere-Zaragoza et al., 1993a:483; González-González 

et al., 1996:202 [non Galaxaura ventricosa Kjellman, 1900:81].

Algae erect, bushy, calcified, pale pink to grayish red, of flattened smooth and regularly subdichotomously branched axes, up 

to 8 cm high, axes 1.0–2.5(–4.0) mm in diameter, of more or less 

uniform width throughout; branch dichotomies 3–10(–15) mm 

apart; attached below by a broad flattened or discoid holdfast. 

Branches glabrous above, often with distinct transverse bands 

(striations where calcification interrupted), margins often thickened; basal portions subterete, often hirsute (hairy). Medullary 

filaments of elongated cells, 8–16 μm in diameter. Gametophyte 

cortex pseudoparenchymatous, of 3 closely packed cell layers, 

inner 2 layers of large colorless subglobose cells, and single outer 

layer of pigmented smaller cells (15–)20–30(–35) μm in diameter, polygonal in surface view (4–6 sided). Surface cortical cells 

commonly bearing spinulose (apiculate) epidermal cells along 

the axes margins and occasional in patches elsewhere; spinulose 

cells 30–40 μm long by 10–15 μm in diameter, with a rounded 

or mucronate apex. Sporophytes not found in our collections; as 

reported from elsewhere (Wang et al., 2005): cortex of 4–5 layers; inner layers of large, colorless, globose cells; outermost layer 

of pigmented subspherical cells borne singly or in pairs on elongate, loosely spaced stalk-like cells; subspherical cells sometimes 

apiculate (see Huisman, 2006: fig. 5b), with a short simple spine 

on their external surface, particularly on cells near axes margins 

(Wiriyadamrikul et al., 2014: fig. 6-I).

Tetrasporangia cruciately divided; borne laterally on subepidermal stalk cells or terminally on outermost cortical cells. 

Gametophytes usually dioecious. Spermatangia in conceptaclelike cavities (Figure 24B, C).

Habitat. On rocks; low intertidal to shallow subtidal; dredged to 40 m depths. 

Distribution. Gulf of California: Puerto Peñasco; 

Punta Cirio to Guaymas; Caleta Santa María (about 11.3 km [7 

miles] north of Santa Rosalía) to Bahía Agua Verde; Bahía de 
5 4 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

La Paz to Punta Los Frailes; Nayarit to Jalisco; Isla María Magdalena (Islas Marías; Islas Tres Marías). Eastern Pacific: Costa 

Rica; Galápagos Islands. Central Pacific: Hawaiian Islands. 

Western Pacific: China; Taiwan; Korea; Japan.

Type Locality. “On the shore of one of the Bahama Islands” (Ellis and Solander, 1786:115).

Remarks. Molecular phylogenies based on rbcL sequence data (Wang et al., 2005; Wiriyadamrikul et al., 2014: fig. 

1) indicate specimens identified as D. marginata from around 

the world are not monophyletic but instead diverge into several 

clades. Dichotomaria marginata is currently a species complex in 

need of taxonomic revision (Wang et al., 2005; Huisman et al., 

2004b; Huisman, 2006). Northern Gulf specimens from Guaymas identified as D. marginata grouped in a clade near specimens of D. tenera from South Africa (Wang et al., 2005: figs. 8, 

9; Liu et al., 2013: fig. 1). Gulf of California D. marginata and 

South African D. tenera (De Clerck et al., 2005a) are similar in 

morphology, and both have small axes diameters of 1–2(–3) mm. 

The sporophytes of these two species have been separated on the 

presence or absence of apiculate ends on their ultimate epidermal 

cells. They are often present on those of D. marginata, particularly on cells along the axes margins (Huisman et al., 2004b), 

and they are absent from ultimate epidermal cells of D. tenera. 

However, apiculate epidermal cells have since been occasionally 

observed on D. tenera sporophytes, so this feature is apparently 

not entirely consistent (De Clerck et al., 2005a). 

Only gametophytic thalli of Dichotomaria marginata were 

found in our northern Gulf collections. The specimens generally 

agree in external morphology and internal anatomy with Australian D. marginata (see Huisman and Kurihara, 2006:17), although 

FIGURE 24. A–C. Dichotomaria marginata: A. Habit of gametophyte (JN-3400a, US Alg. Coll.-159143). B. Transection of male gametophyte

showing two embedded spermatangial cavities and tightly arranged outer cortical cells (epidermis) bearing spinulose cells. C. Transection showing densely branched spermatangial filaments projecting into cavity of male conceptacle (B, C JN-4891a, US Alg. Coll. microscope slide 8707). 
NUMBER 96 • 5 5

size measurements of Gulf specimens are smaller. Branches of

Gulf of California specimens of D. marginata (JN-4891a, US Alg. 

Coll.-159149; and JN-3400a, US Alg. Coll-159142), when viewed 

under a dissection scope, reveal tiny brown spinulose cells bristling along their axes margins, whereas in the middle, the branches 

are pink and shiny, with a reflective sparkle off the cortical surface.

Detailed comparative morphological studies and phylogenetic analyses of DNA sequences of Gulf of California D. marginata are needed to determine if they are in agreement with type 

locality material (Bahamas Islands) or are possibly a separate entity. The Gulf D. marginata should also be studied to understand 

its relationship to Gulf specimens identified with D. spathulata.

Dichotomaria spathulata (Kjellman) A. Kurihara et Huisman

FIGURE 25

Galaxaura spathulata Kjellman, 1900:74, pl. 12: figs. 5–12, pl. 20: fig. 

35; Taylor, 1945:142; Dawson, 1961b:407; Fernández-García et al., 

2011:61. 

Dichotomaria spathulata (Kjellman) A. Kurihara et Huisman in Huisman 

and Kurihara, 2006:21, 135, figs. 5C, 6B. 

Galaxaura arborea Kjellman, 1900:72, pl. 11: figs. 1–11, pl. 20: fig. 39; 

Tanaka, 1936:161, figs. 24, 25, pl. 40; Tseng, 1941:94, fig. 6; Chou, 

1945:50, pl. 5: figs. 2–5, pl. 10: figs. 1, 2; Dawson, 1953a:49, pl. 17: fig. 

2; 1959a:5, 6, 19; 1961b:407; 1962d:394; 1966a:15; Zhou and Chen, 

1983:87, pl. 1: fig. 6; Tseng, 1983:58, pl. 32: fig. 2; Norris, 1985d:211; 

Huerta-Múzquiz and Mendoza-González, 1985:48; Anaya-Reyna and 

Riosmena-Rodríguez, 1996:864, tbl. 1; Riosmena-Rodríguez et al., 

1998:28; CONANP, 2002:141; Fernández-García et al., 2011:61. 

Galaxaura marginata sensu Dawson, 1944a:258 [non Galaxaura marginata

(J. Ellis et Solander) J. V. Lamouroux, 1816:264, which is now Dichotomaria marginata (J. Ellis et Solander) Lamarck, 1816:146].

Algae erect, bushy, composed of flattened calcified axes, 

grayish green to reddish brown, up to 12 cm tall; above a terete 

to compressed stipe, 1–4 mm long; attached below by a small 

holdfast of compacted rhizoidal cells. Axes 1–3 mm wide and 

250–400 μm thick. Surfaces of axes with transverse bands or 

FIGURE 25. Dichotomaria spathulata: A. Habit, tetrasporophyte (JN-5859, US Alg. Coll.-159150). B, C. Portion of transections through 

sporophyte cortex showing loosely arranged stalk-like cells bearing 1–2 subspherical, nonapiculate ultimate cortical cells (B, JN-4891b, US Alg. 

Coll. microscope slide 8708; C, JN-2941, US Alg. Coll. microscope slide 5366). 
5 6 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

striations where calcification has been interrupted; axes repeatedly subdichotomously branched, up to 6 orders. Medulla filamentous. Sporophyte cortex of 4–5 layers; inner 2–3 layers of 

globose colorless cells and borne singly or in pairs above a short 

(about 20 μm long) stalk-like cell, the outermost layer of oval 

to obovoid cells, 30–45 μm tall, 25–35 μm in diameter. Gametophytes (not known in the northern Gulf); elsewhere reported 

with pseudoparenchymatous cortex, of 3–4 compact layers; 

inner 2 layers of colorless, laterally cohering cells, 24–60 μm tall, 

60–80 μm wide; outer layer of smaller, pigmented cells, many 

with spinulose cells at the thallus surface.

Habitat. On intertidal platforms, on rocks, and in 

tide pools; mid to low intertidal. 

Distribution. Gulf of California: Puerto Peñasco; 

Punta Cirio; Bahía de Loreto to Cabo San Lucas. Eastern Pacific: 

Costa Rica; Nicaragua; Galápagos Islands. Central Pacific: Hawaiian Islands. Western Pacific: China; Japan. 

Type Locality. Fremantle, Western Australia, 

Australia. 

Remarks. Only sporophytes of Dichotomaria spathulata were found in our northern Gulf collections as well as 

those of Dawson (1966a, as “Galaxaura arborea”). Galaxaura 

arborea was considered to be conspecific with D. spathulata by 

Huisman and Kurihara (2006). Morphologically, the Gulf of 

California specimens referred to D. spathulata are on the small 

end of the size range for the species, with branches up to 3 mm 

in width. Sporophytes of Australian D. spathulata (Huisman and 

Kurihara, 2006:21) can have wider axes (up to 5 mm) and also 

differ in being more sparingly branched, with longer intervals between dichotomies. Structures, possibly immature tetrasporangia 

(not yet divided), were observed to be terminal on some epidermal cells of northern Gulf D. spathulata (JN-4833, US Alg. Coll. 

microscope slide 5250). If they are sporangia, then the Gulf tetrasporangia differ in position from tetrasporangia reported for 

Australian D. spathulata, which are borne laterally from the subepidermal cells (stalk cells). 

Outside the Gulf of California, sporophytes of D. spathulata from Pacific Mexico and Costa Rica (Chou, 1945; Dawson, 1953a, both as “Galaxaura arborea”) were found growing 

sympatrically among gametophytes identified as “Galaxaura veprecula.” The ecological association of the two suggested they 

might be life history phases of a single species, and they were 

later treated as being conspecific (Papenfuss et al., 1982). However, more recently, Huisman and Kurihara (2006) considered 

G. veprecula Kjellman (1900; type locality: Madagascar) to be 

a synonym of Dichotomaria marginata (J. Ellis et Solander) 

Lamouroux.

Dichotomaria spathulata is currently reported as being 

widespread in distribution. Phylogenetic analyses of DNA sequences are needed to assess whether Gulf of California algae referred to D. spathulata, as well as those from around the world, 

are identical with type or type locality material (Western Australia) or are perhaps separate species. 

Galaxaura J. V. Lamouroux

Galaxaura J. V. Lamouroux, 1812:185.

Algae of erect, calcified, subdichotomously branched terete 

axes of multiaxial construction. Gametophytes and tetrasporophytes are dimorphic, both having a filamentous medulla, but 

differ in external morphology and in cortical anatomy. Gametophytes have smooth surfaces (glabrous) or partly smooth in the 

upper portions and with hairy surfaces in lower portions. The 

cortex of gametophytes is typically 3 layers thick: inner 2 layers 

of large colorless cells that are often laterally adjoined (fused) 

and an outer layer of smaller tightly arranged pigmented cells. 

The cortex of sporophytes is composed of supporting cells bearing short and long assimilatory filaments, giving the surface a 

hairy appearance. The assimilatory filaments/hairs are supported 

on inflated or noninflated basal cells.

Sporophytes produce cruciately divided tetrasporangia. Tetrasporangia develop laterally or terminally on the assimilatory 

filaments that extend beyond the thallus surface. 

Gametophytes are usually dioecious, although some are monoecious. Carpogonial branches are 3-celled, developing in place of 

a vegetative filament. Before fertilization the hypogynous cell of the 

carpogonial branch bears 3–4 nutritive filaments, and the basal cell 

has 3–4 sterile filaments of 3–4 small cells. The filaments derived 

from the basal cell do not form a pericarp but remain at the base 

of the cystocarp in Galaxaura (Wang et al., 2005). The primary 

gonimoblast filaments are initiated from the fertilized carpogonium 

and form most of the cystocarpic conceptacle wall. A fusion cell 

is formed from the carpogonium, hypogynous cell, basal cell, and 

part of conceptacle wall filaments (i.e., inner gonimoblast cells). 

Cystocarps are immersed within the axes, with carposporangia 

terminal on gonimoblast filaments that arise from the conceptacle 

wall and grow toward the center of the cystocarpic cavity (Huisman, 2006). Spermatangia are formed in conceptacle-like cavities. 

Remarks. The generic name, Galaxaura (Greek: Galaxaurh), is after one of the Okeanides (Oceanides), the three 

thousand goddess nymphs who were daughters of Okeanos

(Oceanus) and Tethys (Huisman, 2006). 

Two species of Galaxaura occur in the northern Gulf of 

California.

KEY TO THE SPECIES OF GALAXAURA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thallus pinkish to peach colored, generally wider and with smooth branch surfaces in upper parts; cortex of lower portions of thallus often with sparse to dense assimilatory filaments/hairs (gametophyte) . . . . . . . . . . . . G. rugosa (in part)

1b. Thallus usually dark reddish; surface hairy (hirsute) throughout, cortex with short and long extended assimilatory filaments/hairs (in whorls or not in whorls) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
NUMBER 96 • 5 7

2a. Short assimilatory filaments commonly composed of 3 cells (occasionally 2) (sporophyte) . . . . . . . . G. rugosa (in part)

2b. Short assimilatory filaments mostly of 2-cells (infrequently of 3 cells) (sporophyte) . . . . . . . . . . . . . . . . . . . G. ramulosa

Galaxaura ramulosa Kjellman

FIGURE 26

Galaxaura ramulosa Kjellman, 1900:50, pl. 3: figs. 24–26, pl. 4: figs. 1–3, 

pl. 20: fig. 18; Chou, 1945:44, pl. 2: figs. 3–5, pl. 7: fig. 1; Taylor, 

1945:140; Dawson, 1957c:13; 1961b:407; 1962b:229; 1966a:15; 

1966b:59; González-González et al., 1996:202; Bernecker, 2009:CDRom p. 61.

Tetrasporophytes up to 6(–10) cm tall; axes terete, 0.5–1.2 

mm in diameter; dichotomously to subdichotomously branched, 

heavily calcified. Dichotomies 2–15 mm apart; surface mostly 

hairy (hirsute), but may become denuded in lower portions. 

Assimilatory filaments/hairs occasionally in whorls. Medullary 

filament cells elongate, 6–20 μm in diameter. Cortex of cortical 

supporting cells, 30–35 μm tall by 20–40 μm wide; each support 

cell often with both a short and a long extended assimilatory filament on a tumid basal cell. Short assimilatory filament, usually 

of 2 cells (infrequently 3): a tumid basal cell, 40–65 μm long by 

20–40 μm in diameter, and a subglobose terminal cell, 20–32 μm 

in diameter (usually nearly the same diameter as basal cell). Long 

assimilatory filaments (also on a tumid basal cell) 0.8–1.2 mm 

long, of cells 18–60 μm in length, 12–15 μm in diameter basally, 

cells wider above to 18–20 μm in diameter.

Gametophytes unknown in Gulf of California collections. 

Habitat. On rocks and tidal platforms and in tide 

pools; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco; 

Bahía de San Carlos (“Nuevo Guaymas”), north of Guaymas. 

Eastern Pacific: Costa Rica; Panama.

Type Locality. [Probably Recifie], Pernambuco, 

Brazil.

Remarks. Only the sporophyte of Galaxaura ramulosa is thus far reported in the northern Gulf of California. It has 

extended assimilatory filaments that resemble those described 

for sporophytes of other species (see Tanaka, 1936: Chou, 1945; 

Wang et al., 2005), e.g., G. delabida Kjellman (1900) and G. lapidescens, that have been considered conspecific with G. rugosa. 

Dawes and Mathieson (2008) list G. ramulosa in synonyms of

G. rugosa, but without comment. Northern Gulf specimens referred to G. ramulosa and Brazilian G. ramulosa (type and type 

locality) need to be comparatively tested with DNA sequence 

analyses to clarify their phylogenetic relationship, and then compared to G. rugosa.

Galaxaura rugosa (J. Ellis et Solander) J. V. Lamouroux

FIGURE 27

Corallina rugosa J. Ellis et Solander, 1786:115, pl. 22: fig. 3. 

Galaxaura rugosa (J. Ellis et Solander) J. V. Lamouroux, 1816:263; Papenfuss et al., 1982:421, figs. 17–19, 29, 40, 41, 45; Huisman and 

Borowitzka, 1990:153, figs. 1–13; Dreckmann, 1991:33; León-Tejera 

et al., 1993:200; Mateo-Cid et al., 1993:47; León-Tejera and GonzálezGonzález, 1993:496; González-González et al., 1996:390; Yoshida, 

1998:502; Abbott, 1999:68, fig. 8A–E; Cruz-Ayala et al., 2001:191; 

CONANP, 2002:141; Huisman et al., 2004c:344, figs. 1–6; Wang et 

al., 2005:693, figs. 3d–g, 4a–i, 6c–f, 7a–e; Mateo-Cid et al., 2006:55; 

Huisman, 2006:22, fig. 7A–G; Serviere-Zaragoza et al., 2007:9; Y.-

P. Lee, 2008:220, figs. A–D; Bernecker and Wehrtmann, 2009:226; 

Fernández-García et al., 2011:61.

Corallina lapidescens J. Ellis et Solander, 1786:112, pl. 22: fig. 9.

Galaxaura lapidescens (J. Ellis et Solander) Lamouroux, 1816:264; Taylor, 

1960:337; Papenfuss et al., 1982:407, figs. 4, 5, 22, 23, 34, 44.

Galaxaura squalida Kjellman, 1900:55, pl. 6: figs. 1–12, pl. 20: fig. 9; Svedelius, 1945:3, figs. 1–7, pl. 1; Taylor, 1945:142; Chou, 1947:9, pl. 4: 

figs. 1–11, pl. 8: fig. 2; Dawson, 1953a:52, pl. 19: fig. 1; 1961b:407; 

1962b:198, 229, fig. 73; 1966a:15; Zhou and Chen, 1983:83, pl. 2: figs. 

6, 7; Huerta-Múzquiz and Mendoza-González, 1985:48; GonzálezGonzález et al., 1996:311; Anaya-Reyna and Riosmena-Rodríguez, 

1996:864, tbl. 1; Riosmena-Rodríguez et al., 1998:28.

Galaxaura subfruticulosa R. Chou in Taylor, 1945:140; Chou, 1945:41, pl. 

2: fig. 6, pl. 8: fig. 2; Dawson, 1953a:52, pl. 20: fig.1; 1961b:407; Itono, 

1977b:6, fig. 4; Papenfuss et al., 1982:409; Tseng, 1983:60, pl. 33, fig. 

4; Zhou and Chen, 1983:87, pl. 1: fig. 5; González-González et al., 

1996:202. 

Galaxaura subverticillata Kjellman, 1900:48, pl. 3: figs. 12–14, pl. 20: fig. 

17; Tanaka, 1936:146, figs. 3, 4, pl. 34: fig. 2; Dreckmann, 1991:33; 

Yoshida, 1998:503.

Gametophytic and tetrasporophytic thalli are dimorphic, 

differing in external morphology and cortical anatomy. Gametophytes erect, forming clumps 4–8(–10) cm tall, branches terete, glabrous (without hairs) in upper parts, with assimilatory 

filaments/hairs on outer cortical cells of lower portions. Thalli 

light pink, yellowish green, or peach colored, with rosy orange 

apices; branches mostly (2.0–)5–12 mm long, 1–2 mm in diameter; slightly segmented (not constricted) and repeatedly dichotomously to subdichotomously branched; attached by a discoid, 

expanding holdfast. Heavily calcified throughout, with evident 

annulations (transverse striations) interrupting calcification in 

upper portions. Cortex 3(–4) cell layers thick, inner two cortical 

layers of large, subglobose cells, 20–40 μm tall by 25–40 μm in 

diameter; innermost cells often fuse with adjacent cortical cell 

becoming larger, much wider than tall, 20–30 μm tall, 25–80 

μm in width, and sometimes fused with 2–3 lobes (in longitudinal section); middle layer of globose to ovate cells, 15–30 μm 

tall, 15–25(–30) μm in diameter. Outer layer of flat-topped pigmented angular cells (4–7 sided); in surface view 14–22 μm wide, 

with a single stellate chloroplast and central pyrenoid; surface 

cells in cross section 8–12(–15) μm tall by 18–25 μm wide. 

Gametophytes apparently dioecious. Cystocarps spherical, embedded in medulla, with ostiole opening through cortical layer to thallus surface; mature carposporangia about 50 

μm long by 30 μm in diameter. Spermatangial reproduction unknown in Gulf material (reported from elsewhere: spermatangial cavities 230–450 μm in diameter; inner parent cells cutoff 
5 8 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 26. Galaxaura ramulosa: A. Habit of sporophyte (JN-3563, US Alg. Coll.-159169). B. Sporophytic specimen with dark reddish extended assimilatory filaments in whorls (EYD-27457, US Alg. Coll.-40824). C. Transection of branch showing cortex of tangled filaments and 

supporting cells that bear inflated basal cells with long or short assimilatory filaments (JN-3080, US Alg. Coll.-159167). D, E. Separated cortical 

filaments showing supporting cell bearing one or two tumid cells each with a single short or long assimilatory filament. Short filaments consist 

of a tumid cell and a terminal cell (occasionally one additional cell), with the terminal cell subglobose or sometimes flat topped (D, E, JN-4280, 

US Alg. Coll. microscope slide 8697).
NUMBER 96 • 5 9

highly branched, spermatangial filaments that develop terminal 

and subterminal spermatangia, 7–10 μm in diameter [after Wang 

et al., 2005]).

Tetrasporophytes, dark red in color, up to 8 cm tall (generally shorter in height with axes thinner in diameter than 

gametophytes); subdichotomously branched; branch segments 

3–7 mm long; surface characteristically furry or hairy; with simple or sometimes branched, extended assimilatory filaments, up 

to 1.0 mm in length, arising from inflated basal cells of cortical 

layer; intermixed long (5- to 12-celled or more) and short (2- to 

FIGURE 27. Galaxaura rugosa: A. Habit of gametophyte (JN-3634, US Alg. Coll.-159199). B. Transection of 

gametophyte cortex showing lateral fusion of colorless cortical cells and outermost layer of smaller pigmented 

cells. C, D. Small portion of gametophyte cortex showing lateral fusions of inner cells and the occasional extended 

assimilatory filaments (B–D, JN-3077, US Alg. Coll. microscope slide 8698).
6 0 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

3-celled) assimilatory filaments of elongated cells, 22–30(–54) 

μm in length and 14–18 μm in diameter, slightly narrower proximally. Medullary filaments 6–18 μm in diameter. Cortical layer 

of tumid, oval to pyriform, basal cells, 45–65 long by 28–40 in 

diameter; with a subglobose terminal cell 20–35 μm in diameter 

(similar or smaller in diameter than subterminal and basal cells). 

Tetrasporangia globose to ovoid, 27–33 μm in diameter; terminal on long and short assimilatory filaments (after Huisman, 2006). 

Habitat. On rocks; low intertidal to shallow subtidal, down to 10 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena. Eastern Pacific: Punta Palmilla (Baja California Sur); Isla Clarión (Islas Revillagigedo); Costa Rica; Panama. 

Central Pacific: Hawaiian Islands. Western Pacific: Japan; Taiwan; China; Korea.

Type Locality. Jamaica, Greater Antilles, Caribbean Sea. 

Remarks. Gametophytes of Galaxaura rugosa are 

generally wider, pinkish to peach in color, with smooth branch 

surfaces, distinguishing them from the other terete species of Galaxaura in the northern Gulf. Gulf of California tetrasporophytes 

are reddish, often dark red, with hirsute (hairy) branch surfaces 

covered in dark red extended assimilatory filaments. 

Wang et al. (2005), comparing molecular analyses from 

specimens of Taiwan G. rugosa with those from other Pacific 

and Atlantic locales, demonstrated the species was polyphyletic. Analysis of rbcL sequence data revealed that three clades 

separated out in their phylogenetic trees, with each clade correlated to morphological differences of the sporophytes—i.e., 

the absence or presence and numbers and density of long and 

short assimilatory filaments borne on tumid basal cells. The G. 

rugosa complex is in need of taxonomic revision (Wang et al.. 

2005), and may possibly include overlooked species as well as 

some of the species currently considered to be conspecific. Testing of gametophytes and tetrasporophytes of Gulf of California 

G. rugosa will help elucidate their relationship to Caribbean G. 

rugosa (type locality: Jamaica) and the western Pacific G. rugosa 

of Wang et al. (2005).

Tricleocarpa Huisman et Borowitzka

Tricleocarpa Huisman et Borowitzka, 1990:164.

The gametophyte and tetrasporophyte phases of Tricleocarpa species are heteromorphic. Tetrasporophytes are minute, 

branched, Acrochaetium-like filaments (not yet discovered in the 

Gulf of California), and gametophytes are macroscopic, erect, 

calcified, subdichotomously branched fronds (proliferations 

rare). Axes of gametophytes are terete with a smooth surface 

devoid of hairs (glabrous) or hirsute only in the basal portion, attached by discoid holdfasts. The medulla is composed 

of branched longitudinal filaments. The cortex is of 3 or 4 cell 

layers, with cortical filament cells that remain separate (i.e., not 

fusing with adjacent cells). Cortical filaments are dichotomously 

branched, with inner layers of large, nearly colorless cells, and 

outer layers of progressively smaller pigmented cells. 

Gametophytes may be dioecious or monoecious. Carpogonial branches are 3-celled and are borne in the position of normal vegetative filaments; prior to fertilization the basal cell of the 

carpogonial branch produces 4–5 branches that contribute to the 

pericarp of the immersed cystocarp, whereas the hypogynous cell 

cuts off 3–4 nutritive branches. The gonimoblast initials originate directly from the fertilized carpogonium and grow laterally 

along the base of the pericarp, or in some species also contribute 

to the walls of the pericarp as they intermingle with filaments of 

the pericarp (Huisman, 2006). Carposporangia are borne terminally on gonimoblast filaments that extend toward the center 

of the cystocarpic cavity. Pericarp filaments can extend from the 

cystocarp wall to produce paraphyses that may or may not intermingle with the gonimoblast filaments. Cystocarps are immersed 

within the outer medulla of axes and are ostiolate. Spermatangia 

are formed in cavities within the axes.

Tetrasporophytes produce cruciately divided tetrasporangia 

that are borne laterally or terminally on Acrochaetium-like filaments (Magruder, 1984, as Galaxaura oblongata; Huisman and 

Borowitzka, 1990).

Two species of Tricleocarpa occur in the northern Gulf of 

California. 

KEY TO THE SPECIES OF TRICLEOCARPA IN THE NORTHERN GULF OF CALIFORNIA

1a. Axes 0.8–1.3 mm in diameter; cystocarp cavity with well-developed sterile paraphyses that intermingle with gonimoblast; 

gonimoblast filaments line the pericarp and protrude into the cystocarpic cavity from all around the pericarp . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. cylindrica

1b. Axes 1.5–2.0 mm in diameter; cystocarp cavity with poorly developed sterile paraphyses that do not intermingling with 

gonimoblast; gonimoblast filaments grow laterally along the base of the cystocarp cavity . . . . . . . . . . . . . . . . T. fragilis

Tricleocarpa cylindrica (J. Ellis et Solander) Huisman et 

Borowitzka

FIGURE 28

Corallina cylindrica J. Ellis et Solander, 1786:114, pl. 22: fig. 4. 

Tricleocarpa cylindrica (J. Ellis et Solander) Huisman et Borowitzka, 

1990:164, figs. 40–45, 50–52; Dreckmann, 1991:33; Yoshida, 

1998: 508, fig. 3-91I–K; Mendoza-González and Mateo-Cid, 

1999:40, figs. 2–5; Abbott, 1999:73, fig. 10A; Huisman, 2006:25, 

fig. 9A–E; Mateo-Cid et al., 2006:55; Y.-P. Lee, 2008:221, figs. 

A–E; Bernecker and Wehrtmann, 2009:226; Fernández-García et 

al., 2011:65. 

Galaxaura cylindrica (J. Ellis et Solander) J. V. Lamouroux, 1821:22, pl. 

22: fig. 4; Itono, 1977b:14, figs. 17, 19, 37; Salcedo-Martínez et al., 

1988:83.
NUMBER 96 • 6 1

Galaxaura fastigiata Decaisne, 1842b:116; Tanaka, 1936:157, figs. 20, 21, 

pl. 37: fig. 2; Dawson, 1944a:258; Svedelius, 1945:28, figs. 14–16, 

pls. 4, 5, pl. 6: fig. 2; Dawson, 1953a:50, pl. 20: fig. 2; 1959a:20; 

1961b:407; 1966a:15; Itono, 1977b:12, figs. 15, 34; Pedroche and 

González-González, 1981:66; Stewart and Stewart, 1984:142; Norris, 

1985d:212; León-Tejera et al., 1993:200; González-González et al., 

1996:202. 

Galaxaura oblongata sensu Taylor, 1945:143; Chou, 1947:7 [both in part, 

with reference to Pacific Mexico material; non Galaxaura oblongata

(Ellis et Solander) Lamouroux, 1816:262, which is Tricleocarpa fragilis

(Linnaeus) Huisman et R. A.Townsend, 1993:100].

Thalli forming clumps of erect, terete, subdichotomously 

branched fronds; up to 6 cm tall, axes 0.8–1.3 mm in diameter; 

pale pink to purple-gray, surface glabrous, sometimes with faint 

annulations; attached below by a small discoid holdfast. Calcification heavy, restricted to cortical layers; usually fractured at 

nodes/branching points (thus not truly segmented), causing internodes to assume tubular appearance. Medulla composed of 

longitudinal filaments (mostly 5–20 μm in diameter), giving rise 

to dichotomously branched cortical filaments. Cortex 3–4 layers thick; inner layers of large rotund cells, slightly longer than 

wide (18–35 μm in diameter), fusions absent between adjacent 

cells; outer layers of progressively smaller pigmented round cells; 

outer cells in surface view 5–6 sided, 9–20 μm wide

Reproduction as for genus. Gametophytes usually dioecious. Gonimoblast filaments lining the pericarp and projecting 

into the cystocarpic cavity from all directions; sterile paraphyses 

well developed and projecting into the cavity as well, intermingling with gonimoblast filaments (Huisman, 2006). 

Habitat. On rocks, mid intertidal to shallow 

subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena; Nayarit to Jalisco; Isla María Madre (Islas 

Marías; Islas Tres Marías). Eastern Pacific: Isla Guadalupe; Bahía 

Sebastián Vizcaíno, Baja California Sur; Guererro to Oaxaca; El 

Salvador; Nicaragua; Costa Rica; Peru. 

Type Locality. West Indies (Ellis and Solander, 

1786); type lost, lectotype illustration of Ellis and Solander (1786: 

pl. 22: fig. 4) selected by Papenfuss et al. (1982:416, fig. 26).

Remarks. Gulf of California specimens are tentatively referred to Tricleocarpa cylindrica, and their identification requires more investigation. In their phylogenetic study, 

FIGURE 28. Gametophytes of Tricleocarpa cylindrica: A. One frond from a clump, surface smooth and heavily calcified (JN-5955, US 

Alg. Coll.-159165). B. Cortical filaments separated out from the cortex, showing adjacent large inner cortical cells not fusing, and outer layer of 

smaller pigmented cells (JN-3078, US Alg. Coll.-8699).
6 2 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Wiriyadamrikul et al. (2013: fig. 1) found those from the Caribbean Sea (Western Atlantic) and some from southeast Asia and 

Hawaii (Western and Central Pacific) to be T. cylindrica. However a northern Gulf of California “T. cylindrica” from Guaymas, 

Sonora (AY688015; Wang et al., 2005) was revealed to be different from T. cylindrica and T. fragilis. Wiriyadamrikul et al. (2013) 

suggested the Guaymas specimen might be “Galaxaura constipata

Kjellman,” a Western Atlantic species described from Veracruz 

(Gulf of Mexico), and one of several members of Galaxaura sect. 

Eugalaxaura Descaine (1842b) recognized by Kjellmann (1900). 

Wiriyadamrikul et al. (2014: fig. 1), however, later referred to the 

Guaymas specimen (AY688015) as “T. cylindrica.”

Tricleocarpa fragilis (Linnaeus) Huisman et R. A. Townsend

Eschara fragilis Linnaeus, 1758:805.

Tricleocarpa fragilis (Linnaeus) Huisman et R. A. Townsend, 1993:100, 

fig. 1 [lectotype]; Yoshida, 1998:508; Abbott, 1999:74, fig. 10B–G; 

L. Aguilar-Rosas et al., 2000:130; Huisman, 2006:28, figs. 8B, 9F–H; 

Fernández-García et al., 2011:65. 

Dichotomaria fragilis Lamarck, 1816:145.

Galaxaura fragilis (Linnaeus) Lamouroux ex Decaisne, 1842b:116. 

Corallina oblongata J. Ellis et Solander, 1786:114, pl. 22: fig. 1.

Galaxaura oblongata (J. Ellis et Solander) J. V. Lamouroux, 1816:262; Tseng, 

1941:93; Chou, 1947:7, pl. 2: figs. 1–16, pl. 3: figs. 1–14, pl. 10: figs. 

1, 2; Itono, 1977b:13, figs. 18, 36; Papenfuss et al., 1982:416; Zhou 

and Chen, 1983:80, pl. 1: fig.1; Tseng, 1983:60, pl. 33: fig. 1; MateoCid and Mendoza-González, 1992:19; Mateo-Cid et al., 1993:47; 

Mendoza-González et al., 1994:105; Mateo-Cid et al., 2000:63. 

Tricleocarpa oblongata (J. Ellis et Solander) Huisman et Borowitzka, 

1990:168, figs. 46–49, 53–56; Dreckmann, 1991:33; Bula-Meyer, 

1995:33; Cruz-Ayala et al., 2001:191.

Gametophytes forming clumps, up to 6 cm tall; branches 

terete, 1.5–2.0 mm in diameter; calcified, pale pink to gray, subdichotomously branched; attached by discoid holdfast. Axes 

segmented, segments mostly 6–10 mm long, slightly rounded on 

upper and lower ends; surface glabrous (without hairs). Medulla 

of slender filaments, mostly 6–8 μm in diameter, giving rise to 

cortical filaments. Cortex of 3–4 layers of cells; inner cortical 

cells large, colorless, 20–30 μm in diameter; outer surface cells, 

pigmented, more or less globose, 8–15 μm in diameter. 

Tetrasporophytes not known in the Gulf of California. 

Gametophytes dioecious or monoecious. Basal cell of the carpogonial branch with 4–5 branches; hypogynous cell with 3–4 

nutritive branches. Cystocarps globose to subglobose, 400–500 

μm in diameter; cystocarp cavity with gonimoblast filaments 

lining base of pericarp; and paraphyses poorly developed, 3- to 

4-celled, on inner side of pericarp (after Huisman, 2006). Carposporangia 45–65 μm long and 25–40 μm in diameter. Spermatangia borne in spherical cavities.

Habitat. On rocks, tidal platforms, and in tide 

pools; mid to low intertidal.

Distribution. Gulf of California: El Faro de San 

Felipe to Bahía Concepción; Punta Arena to Bahía de La Paz; 

Mazatlán, Sinaloa.

Type Locality. “Oceano Americano” (Linnaeus, 

1758); Jamaica (see Huisman and Townsend, 1993).

Remarks. Presence of Tricleocarpa fragilis in the 

Eastern Pacific of North America, including the Gulf of California, requires confirmation (Wynne, 2011;Wiriyadamrikul et al., 

2013). Culture studies by Magruder (1984, as “Galaxaura oblongata”) showed the tetrasporophyte in the life history of Hawaiian T. fragilis was heteromorphic, a minute “Acrochaetium-like” 

thallus that produced cruciately divided tetrasporangia, borne 

laterally and terminally on the uniseriate filaments.

Liagoraceae

Liagoraceae Kützing, 1843:321

Gametophytes of this family are usually erect, with axes 

that are terete or slightly compressed, and sparingly to abundantly branched. Thalli are dichotomously, pinnately to irregularly branched; or with a percurrent axes and lateral branches. 

The thalli can be tough and chalky to gelatinous or mucilaginous 

in texture, and most are calcified to some degree, with calcium 

carbonate in the mineral form aragonite or uncalcified. All are 

multiaxial in structure. The medulla is a core of longitudinally 

aligned colorless filaments of similar or assorted diameters, from 

which the anticlinal assimilatory filaments radiate outward to 

form a loosely arranged cortex, not forming a continuous surface layer. Assimilatory filaments are dichotomously to polychotomously branched and are composed of pigmented cells that can 

vary in shape and size throughout the length of the filament.

 Life history, where known, is a alternation of heteromorphic 

generations. The tetrasporophytes are microscopic filaments that 

bear cruciately divided tetrasporangia (known only from culture 

studies). Asexual reproduction is by monosporangia in some 

genera but is unknown in most genera. Gametophytes are typically dioecious, but some are monoecious, or occasionally, both 

types occur in a species. The carpogonial branch is three to many 

celled, straight or curved, and usually borne on an assimilatory 

filament. Carpogonial branches may be compound. The hypogynous cell is typically naked (i.e., nutritive or sterile branches or 

cells are absent). Gonimoblast filaments develop from the fertilized carpogonium (zygote) and are branched and compact in 

some or somewhat diffuse to loose in others, intermingling with 

assimilatory filaments. Terminal cells of the gonimoblast filaments produce carposporangia, or nearly all cells become carposporangia. Carposporophytes develop within the cortex among 

the assimilatory filaments, either with associated sterile filaments 

in various arrangements or without sterile filaments. Carposporangia are undivided or quadripartite (“carpotetrasporangia”). 

Spermatangia are borne in clusters at or near the tips of the assimilatory filaments or in whorls on midcortical cells.

Remarks. One genus, Dermonema Harvey ex Heydrich (1894), is reported in the southern Gulf, with D. virens

(J. Agardh) Pedroche et Ávila-Ortiz (1996; basionym: Nemalion 

virens J. Agardh, 1847) from Isla San Ildefonso, Bahía de La Paz 

to Cabeza Ballena, and Mazatlán (Dawson, 1953b, as N. virens; 
NUMBER 96 • 6 3

Huerta-Múzquiz and Mendoza-González, 1985, as D. frappieri

(Montagne et Millardet) Børgesen; Pedroche and Ávila-Ortiz, 

1996). Originally described from Oaxaca, D. virens is also recorded elsewhere in Pacific Mexico from Islas Revillagigedo 

(Serviere-Zaragoza et al., 2007) and Jalisco to Oaxaca. A second 

species, the Japanese D. pulvinatum (Grunow et Holmes) K.-C. 

Fan (1962; basionym: Nemalion pulvinatum Grunow et Holmes 

in Holmes, 1896) was reported from Bahía Agua Verde (Dawson, 1953b, as N. pulvinatum) and later listed without comment 

from Bahía de Loreto (CONANP, 2002, as N. pulvinatum).

Three genera of the Liagoraceae are known in the northern 

Gulf of California. 

KEY TO THE GENERA OF LIAGORACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Gulf thalli moderately to heavily calcified throughout, coarse grained (mealy, ropy) in texture; medullary filaments relatively few, of large cells, 25–150 (most >40) μm in diameter; spermatangia forming dense, cap-like heads at ends of 

assimilatory filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ganonema

1b. Thalli lightly to moderately calcified, not mealy in texture; medullary filaments of cells, 5.0–50 μm in diameter, with thinner cells more numerous; spermatangia not as cap-like . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Assimilatory filaments dichotomously branched; cystocarp borne on distinct elongated stalk cell (fusion cell including 

cells of carpogonial branch and many cells of the bearing cortical filament); 2 discrete clusters of filaments associated with 

cystocarp, a distal cluster of gonimoblasts, and below a subtending cluster of sterile filaments . . . . . . . . . . . . . . Izziella

2b. Assimilatory filaments di-, tri- or polychotomously branched; cystocarp not borne on an elongated stalk (fusion cell may 

be present but does not include numerous cells of the bearing cortical filament); cystocarp a single cluster that includes 

both gonimoblast and involucral filaments, without a separate cluster beneath it . . . . . . . . . . . . . . . . . . . . . . . . Liagora

Ganonema K.-C. Fan et Y.-C. Wang

Ganonema K.-C. Fan et Y.-C. Wang, 1974:492; Huisman and Kraft, 1994:76 

[emended description].

Algae are erect, calcified or uncalcified, with a texture ranging from solid and chalky to soft and mucilaginous, and attach 

to the substratum by a discoid holdfast. Axes are terete, and dichotomously to irregularly branched or with percurrent axes and 

frequent short lateral branches. Construction is multiaxial, with a 

central core of longitudinally aligned medullary filaments that bear 

lateral radiating assimilatory filaments to form cortical fascicles 

on distinctive isodiametric basal cells. Mature medullary filaments 

are relatively wide, usually >40 μm in diameter. Assimilatory filaments of cylindrical, barrel-shaped or ovoid cells are sparingly or 

much branched, generally dichotomous, but are often unbranched 

for a number of cells near thallus surface. Adventitious rhizoidlike filaments, commonly issued by lower cells of the assimilatory 

filaments and basal cells, descend to join the medulla and then 

produce additional cortical laterals; these are generally simple or 

less robust than original cortical fascicles. Outer cortical cells are 

occasionally with terminal hairs or glandular cells. 

Life histories are heteromorphic but not known in all species. Tetrasporangia (where known) are developed on a filamentous tetrasporophyte. Gametophytes are monoecious or 

dioecious. Carpogonial branches are 3- to 6-celled, straight to 

slightly curved, and borne in positions of vegetative cortical 

laterals and on subsidiary cortical and rhizoid-like filaments. 

Gonimoblast develops directly from the fertilized carpogonium, 

initially by a transverse division, eventually forming a compact 

cluster of gonimoblast filaments with terminal carposporangia. 

Cell fusions are typically lacking. Carposporangia either undivided or quadripartite. Postfertilization filaments arise from 

cells in the vicinity of the carpogonial branch, including those of 

nearby branches and those above and below the supporting cell 

(rarely the supporting cell itself) subtending or forming a partial 

involucre around the gonimoblast. Spermatangia are in dense, 

dendroid clusters, arising on short specialized branches issued 

from apical and subapical cells of the assimilatory filaments. 

Ganonema is represented by one species that is apparently 

restricted to the warmer waters of the Gulf of California.

Ganonema farinosum (J. V. Lamouroux) K.-C. Fan et Y.-C. Wang

FIGURE 29

Liagora farinosa J. V. Lamouroux, 1816:240; Yamada, 1938a:23, figs. 

15, 16, pls. 8–10; Dawson, 1953a:42, pl. 2: figs. 9–12, pl. 14: fig. 1; 

1954b:415, figs. 25d, 26; 1959a:5, 20; 1961b:406; Stewart and Stewart, 1984:142; Huerta-Múzquiz and Mendoza-González, 1985:48; 

Mendoza-González and Mateo-Cid, 1985:30; Sánchez-Rodríguez et 

al., 1989:41; Abbott, 1990a:122, fig. 23 [type specimen]; Dreckmann, 

1991:31; González-González et al., 1996:322; Silva et al., 1996b:232 [as 

“L. farinosa f. pinnatiramosa Yamada”]; Cruz-Ayala et al., 2001:191. 

Ganonema farinosum (J. V. Lamouroux) K.-C. Fan et Y.-C. Wang, 1974:492, 

pl. 94: figs. 1–3, 6, 7, pl. 95: figs. 1–6; Tseng, 1983:53, pl. 29: fig. 2; 

Huisman and Kraft, 1994:83; Yoshida, 1998:511; Abbott, 1999:77, 

fig. 11A–G; Huisman, 2000:30; Abbott et al., 2002:310, fig. 21; Huisman, 2002:821, figs. 118–123; Huisman et al., 2004a:299, figs. 1–12; 

Huisman, 2006:38, figs. 13E–H, pl. 10.

Thalli erect to 18(–25) cm tall, of terete axes and branches, 

mostly 1.0–1.6(–2.5) mm in diameter, moderately to heavily calcified, whitish purple to whitish reddish brown in color, 

coarse grained, mealy in texture; branching variable, generally 

dichotomous but may be pinnately to irregularly branched and 

frequently with lateral proliferations; attached by a small discoid 

holdfast. Multiaxial in construction; medullary filaments longitudinally aligned, broad (up to 150 μm in diameter). Anticlinal 

assimilatory (cortical) filaments extend to 450 μm long, outer 
6 4 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

filament cells cylindrical, 19–22 μm in diameter, cell walls not 

indented at joints. Cortical fascicles with isodiametric basal cells. 

Adventitious rhizoidal-like filaments, issued by lower and basal 

cells of cortical fascicles, join and form part of the medulla and 

produce additional assimilatory filaments.

Tetrasporophyte unknown in the Gulf of California. Gametophytes usually dioecious. Carpogonial branches 4- to 5-celled; 

straight to slightly curved, borne laterally on proximal portions 

of assimilatory filaments. After fertilization, the zygote divides 

transversely, and gonimoblasts develop from the distal cell of the 

initial division. No fusion of carpogonial branch cells occurs. 

Gonimoblast compact with branched radiating filaments, carposporangia terminal on gonimoblast filaments. Some involucral 

filaments loosely surround the gonimoblasts; carposporangia 

elongate, in a compact cluster on short, branched gonimoblast 

filaments. Spermatangia forming dense capitate heads near tips 

of assimilatory filaments.

Habitat. On rocks; shallow subtidal, down to 14 m 

depths.

Distribution. Gulf of California: Isla San Diego to 

Punta San Evaristo; Bahía de La Paz to Punta Los Frailes, Baja 

California Sur. Eastern Pacific: Isla Guadalupe (off Baja California); Bahía San Sebastian Vizcaíno (northern Baja California) to 

Bahía Magdalena (Baja California Sur); Rocas Alijos. Central 

Pacific: Hawaiian Islands. Western Pacific: China; Taiwan; Vietnam; Japan. 

Type Locality. near Suez, Egypt, Red Sea.

Remarks. Thus far, Ganonema farinosum has been 

collected in the southern Gulf of California but is likely to be 

found in the northern Gulf as well. The mealy, coarse-grained 

(farinose) texture, cylindrical outer cells of its assimilatory filaments, and compound cap-like spermatangial branches are diagnostic features of this species.

Izziella Doty

Izziella Doty, 1978:34; Huisman and Schils, 2002:244, tbl. 1.

Thalli are mucilaginous, lightly to moderately calcified, and 

variable in color (typically a whitish green-gray tinged pink). 

Percurrent primary axes bear indeterminate lateral branches, 

and both the axes and lateral branches in turn bear further orders of short lateral branches or become irregularly branched. 

Thalli are multiaxial, with center medulla of colorless, longitudinally aligned filaments (15–50 μm in diameter), bearing 

anticlinal, pigmented, assimilatory filaments. Assimilatory filaments are sparsely, dichotomously branched. Basal cells of the 

FIGURE 29. Ganonema farinosum: A, B. Habit of gametophytes (A, EYD-18914, US Alg. Coll.-8101; B, JN-7173, US Alg. Coll.-160431). 
NUMBER 96 • 6 5

assimilatory filaments issue rhizoidal filaments that add to the 

core of medullary filaments; these also adventitiously produce 

additional assimilatory filaments, although those produced are 

simple or less robust. Cells of assimilatory filaments have a central pyrenoid. 

Carpogonial branches are 3–4(–5)-celled, curved, and borne 

laterally off an assimilatory filament cell. A mature cystocarp 

has two clusters of filaments: the distal cluster of gonimoblast 

filaments with the carposporangia, forming a compact whorl 

around a short longitudinal core of cells that arise from the divided zygote, and, below that, a separate, subtending cluster of 

sterile filaments arising from cells to both sides of the carpogonial branch’s supporting cell. An extensive fusion cell is formed 

that includes cells of the carpogonial branch and many cells of 

the assimilatory filament bearing the carpogonial branch. The 

fusion cell is part of the long stalk that bears the gonimoblast. 

Spermatangia are borne on spermatangial parent cells on terminal and subterminal cells of the assimilatory filaments.

Remarks. The reproductive characteristics differentiating Izziella are its cystocarp borne on an elongated stalk, 

which is composed of a fusion cell incorporating carpogonial 

branch cells and many cells of the bearing assimilatory filament, 

and the cystocarp having two distinct clusters of filaments, an 

upper fertile cluster of gonimoblast filaments and carposporangia and a second cluster of sterile filaments below.

Izziella is represented in the northern Gulf of California by 

one of its four species.

Izziella orientalis (J. Agardh) Huisman et Schils

Liagora orientalis J. Agardh, 1896:99; Yamada, 1938a:4 [in part], fig. 1A–C 

[only], pl. 1; 1944:18; Dawson, 1953a:40, pl. 17: fig. 1; 1954b:415, fig. 

27b; 1961b:406; Abbott, 1990b:314, figs. 7 (lectotype), 8–11; RochaRamírez and Siqueiros-Beltrones, 1991:32; González-González et al., 

1996:237; Riosmena-Rodríguez and Paul-Chávez, 1997:70; Abbott, 

1999:87, figs. 14F–J. 

Izziella orientalis (J. Agardh) Huisman et Schils, 2002:247, figs. 1–9, 17, 18; 

Mateo-Cid and Mendoza-González, 2004:78, figs. 1–19. 

Izziella abbottiae Doty, 1978:34 [as “abbottae”], fig. 10. 

Liagora tanakae I. A. Abbott, 1976:33 [as “L. tanakai”], figs. 1–5.

Algae of 1 to a few terete branched axes, soft and lubricous, 

lightly to moderately calcified, whitish in color, up to 15 cm tall; 

attached by a small discoid holdfast. Axes 3–5 mm in diameter, 

branching more or less pinnate to irregularly pinnate, multifariously arranged; branches mostly 2–3 mm in diameter, branched; 

upper branches about 1.0 mm in diameter. Medullary filaments 

of elongated cells, 10–35(–45) μm in diameter. Rhizoidal-like 

filaments, produced by basal portions of assimilatory filaments, 

become part of the medulla. Assimilatory filaments moniliform, 

dichotomously branched up to 5 orders, 250–350 μm long; basal 

cells narrow, cylindrical, elongated, 21–35(–60) μm long, 6–11 

μm in diameter; outer cells clavate to ovate, 25–30 μm long, 

20–25 μm in diameter; terminal cells to 15 μm in diameter, often 

with terminal hyaline hairs. Cells of assimilatory filaments with 

lobed plastids containing a large central pyrenoid.

Asexual reproduction is not known. Gametophytes dioecious. Carpogonial branch 3- to 5-celled, somewhat curved, 

and borne laterally off a proximal cell of assimilatory filament. 

After fertilization, zygote divides transversely and the distal cell 

undergoes further divisions that develop gonimoblast filaments, 

while the proximal cell of the initial division remains undivided. 

Gonimoblast compact, subglobose cluster, 110–150 μm in diameter, gonimoblast filaments bearing terminal carposporangia. 

Gonimoblast without a surrounding involucre; on cells distal 

and proximal to the the supporting cell below, a smaller cluster of short, sterile filaments develops. An extensive fusion cell 

is formed from cells of the carpogonial branch and many cells 

of the bearing assimilatory filament. The fusion cell lengthens, 

becomes hyaline, and appears as an elongated stalk bearing the 

gonimoblast. Spermatangia in small clusters of 2–4; developed 

from spermatangial parent cells on apical and subapical cells of 

assimilatory filaments; spermatia, 2–3 μm in diameter.

Habitat. On rocks and in tide pools; mid to low 

intertidal.

Type Locality. “Ceylon” (Sri Lanka) (J. Agardh, 

1896).

Distribution. Gulf of California: Ensenada Lalo, 

Sonora; Bahía de La Paz; Nayarit to Jalisco. Eastern Pacific: 

Punta Malarrimo (Bahía Sebastian Vizcaino) to Punta Conejo, 

Baja California Sur; Michoacán to Guerrero; Ecuador. Central Pacific: Hawaiian Islands. Western Pacific: Taiwan; China; 

Japan; Vietnam.

Remarks. Thalli of Izziella orientalis from mainland 

Pacific Mexico have been reported up to 51 cm tall (Mateo-Cid 

and Mendoza-González, 2004), much larger than those found in 

the Gulf of California.

Liagora J. V. Lamouroux

Liagora J. V. Lamouroux, 1812:185.

Gametangial algae are erect above a discoid holdfast, and 

lightly to heavily calcified, with a texture from firm to soft 

and mucilaginous. Axes and branches are terete to somewhat 

compressed and regularly dichotomous, pinnate, or irregularly 

branched. Thalli are multiaxial in construction, with a medulla 

composed of colorless, longitudinally aligned filaments that bear 

pigmented, anticlinal assimilatory filaments that form a loose 

cortex. Assimilatory filaments are dichotomously to trichotomously branched. Narrow rhizoid-like filaments often develop 

from the lower cells of the assimilatory filaments and function as 

medullary filaments and may issue additional assimilatory filaments. Photosynthetic cells of the assimilatory filaments (cortical fascicles) contain a single large parietal plastid and usually 1 

pyrenoid. Outer cortical cells sometimes may bear terminal hairs 

or glandular cells.

The tetrasporic phase in the life history is heteromorphic, 

where known, consisting of uniseriate filaments that develop 

tetrasporangia. Monosporangia are reported in some species, 

borne on the tips of assimilatory filaments. Gametophytes of 
6 6 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

most species are dioecious, but some species are monoecious, 

and other species may be both monoecious and dioecious. Carpogonial branches are generally 3- to 6-celled, with only one 

species issuing (post-fertilization) short sterile filaments from the 

basal cell (i.e., L. tsengii Husiman et M. J. Wynne, 1999). Carpogonial branches are borne laterally on lower to middle cortical 

cells. Fusing cells, although lacking or unknown in many species, 

are reported in some, with fusion cells formed from the cells of 

the carpogonial branch and rarely include the supporting or adjacent cells. Gonimoblasts develop directly from the distal cell of 

the initial transverse division of the fertilized carpogonium and 

form a diffuse or compact cluster of gonimoblast filaments that 

terminate in a single carposporangium or a short chain of carposporangia. Involucral filaments develop from the cells in the 

vicinity of the carpogonial branch, and either remain separate 

or become entwined with the gonimoblast filaments. Carposporangia in most species produce a simple, undivided carpospore, 

but some divide and produce carpotetraspores (4 carpospores). 

Spermatangia develop either singularly or in clusters on the spermatangial parent cells on the outer cortical cells. 

Remarks. Two species have been reported in the 

southern Gulf from Bahía de La Paz: Liagora abbottiae E. Y. 

Dawson (1953b:41, pl. 2: figs. 6–8, pl. 15: fig. 2) by HuertaMúzquiz and Mendoza-González (1985), a Pacific Baja California species described from Punta Santa Rosaliita (note that 

the locality was incorrectly given as “Punta Santa Rosalía” by 

Dawson, 1953b), and L. californica Zeh (1912) by RiosmenaRodríguez et al. (1998) and Cruz-Ayala et al. (2001), a species 

described from Santa Catalina Island (California Channel Islands) and known from southern California to Baja California 

Sur (Dawson, 1953a; Abbott and Hollenberg, 1976; CastañedaFernández de Lara et al., 2010).

Two species of Liagora are found in the northern Gulf of 

California.

KEY TO THE SPECIES OF LIAGORA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli irregularly dichotomously branched, branches with short lateral branchlets; dioecious; gonimoblast surrounded by 

prominent, long, slender involucral filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. magniinvolucra

1b. Thalli regularly dichotomously branched, branches sometimes with proliferous short lateral branchlets; monoecious; 

gonimoblast surrounded by involucral filaments but not long and prominent . . . . . . . . . . . . . . . . . . . . . . L. ceranoides

Liagora ceranoides J. V. Lamouroux

FIGURE 30

Liagora ceranoides J. V. Lamouroux, 1816:239; Yamada, 1938a:20, pl. 6; 

Abbott, 1945:156, figs. 8, 9; Taylor, 1945:135; Dawson, 1957c:13 

[tentatively]; 1961b:406; Abbott, 1990a:118; Dreckmann, 1991:31; 

González-González et al., 1996:322; Abbott, 1999:84, fig. 13I–M; 

Cruz-Ayala et al., 2001:191; Mateo-Cid et al., 2006:55; Bernecker, 

2009:CD-Rom p. 61; Fernández-García et al., 2011:62.

Thalli of 1 to a few cylindrical axes, calcification moderate 

(more or less even throughout), whitish to pale rose in color, 

firm with a gelatinous texture, to 4 cm tall, attached by a small 

discoid holdfast. Axes repeatedly, subdichotomously branched 

from near base; main axes to 1 mm diameter; with or without 

proliferous short lateral branchlets. Assimilatory filaments moniliform, branching at wide angles, dichotomously to trichotomously branched; outer cells to about 10 μm diameter.

Asexual reproduction unknown. Gametophytes monoecious. 

Carpogonial branch curved, of 3–5 cells. Gonimoblast a cluster 

of branched filaments bearing carposporangia terminally and surrounded by a filamentous involucre. Involucral filaments mostly 

unbranched and slender. Spermatangia in small clusters on outer 

cortical cells; borne terminally on spermatangial parent cells.

Habitat. On sides of rocks and crevices and in tide 

pools; low intertidal and also collected in drift. 

Distribution. Gulf of California: Puerto Peñasco; 

Bahía de La Paz. Eastern Pacific: Costa Rica. Central Pacific: Hawaiian Islands. Western Pacific: Japan; China; Taiwan; Vietnam. 

Type Locality. St. Thomas, U.S. Virgin Islands, 

Caribbean Sea.

Remarks. Previously unknown in the northern 

Gulf, drift collections from Playa Las Conchas (Playa Estación), 

Puerto Peñasco (JN-3195, US Alg. Coll.), establish Liagora ceranoides in the northern Gulf of California. The branches of the 

Gulf specimens have short lateral branchlets and seem closest 

FIGURE 30. Liagora ceranoides: Habit of a gametophyte (JN-3195, 

US Alg. Coll.-160430). 
NUMBER 96 • 6 7

to L. ceranoides f. pulverulenta (C. Agardh) Yamada (1938a; 

=Liagora ceranoides var. pulverulenta (C. Agardh) Børgesen, 

1942; basionym: Liagora pulverulenta C. Agardh, 1822. Another form, L. ceranoides f. leprosa (J. Agardh) Yamada (1938a; 

basionym: Liagora leprosa J. Agardh, 1847) has been recorded 

from Pacific Baja California from Punta Malarrimo, Bahía San 

Sebastián Vizcaino and Isla Guadalupe (Dawson, 1953a; Stewart 

and Stewart, 1984). Liagora ceranoides is reportedly widespread 

in tropical to subtropical seas (Abbott, 1990a, 1999), including 

Australia (Huisman, 2006).

Liagora magniinvolucra E. Y. Dawson

FIGURE 31

Liagora magniinvolucra E. Y. Dawson, 1953a:39, pl. 3: figs. 1–11, pl. 16: fig. 

2; 1959a:20; 1961b:406; 1966a:14; 1966b:59; Huerta-Múzquiz and 

Mendoza-González, 1985:48; González-González et al., 1996:237; 

CONANP, 2002:141; Mateo-Cid et al., 2006:50.

Thalli of 1 to a few cylindrical axes, chalky whitish in 

color, up to 15 cm tall, arising from a small discoid holdfast. 

Axes dichotomously branched, with irregularly alternate, short 

branchlets, to 3 mm long. Thalli soft, the calcification mainly on 

surface. Assimilatory filaments, more or less moniliform; inner 

portions with long fusiform cells; outer portions with ovate to 

subclavate cells, 7–12 μm diameter.

Asexual reproduction unknown. Gametophytes dioecious. 

Cystocarp a hemispherical cluster of branched filaments, with 

carposporangia borne terminally, and surrounded by an involucre of long, slender ascending filaments. Spermatangia in clusters 

at ends of assimilatory filaments. 

Habitat. On sides of rocks; mid to low intertidal. 

Distribution. Gulf of California: Playa Arenosa, 

Puerto Peñasco; Isla de San Diego to Cabo Pulmo.

Type Locality. Cabeza Ballena, Baja California 

Sur, Gulf of California, Mexico. 

FIGURE 31. Liagora magniinvolucra: A. Habit of gametophyte (R.D. Staker, s.n., US Alg. Coll.-204280). B, C. Slender longitudinal 

medullary filaments bearing subdichotomously branched anticlinal assimilatory filaments that form the cortex (JN-4046, US Alg. Coll. 

microscope slide 4283).
6 8 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Scinaiaceae

Scinaiaceae Huisman, J. T. Harper et G. W. Saunders, 2004b:228.

Family members are uncalcified, with markedly heteromorphic life history phases (where known). Sporophytes can be minute, uniseriate branched filaments, as discovered in the life cycles 

of Scinaia and Gloiophloea J. Agardh (1872), or crustose thalli, 

as found in Nothogenia Montagne (1843); both kinds of sporophytes produce tetrasporangia. Gametophytes are erect, macrothalli with axes ranging from terete to compressed or somewhat 

flattened, that are usually dichotomously or subdichotomously 

branched, rarely trichotomously or irregularly branched. Gametophytic thalli are multiaxial in structure, with longitudinally 

aligned medullary filaments that issue anticlinal, subdichotomously branched filaments that ultimately form the cortex. The 

cortex remains filamentous (composed of free filaments) or can 

become pseudoparenchymatous when ultimate cortical cells (at 

times colorless utricles) cohere laterally, forming a continuous 

surface layer as in species of Scinaia.

Gametophytes develop three-celled carpogonial branches on 

inner cortical filaments composed of a basal cell, a hypogynous 

cell, and a carpogonium. The hypogynous cell bears nutritive 

branches, and branched gonimoblast filaments develop directly 

from the fertilized carpogonium (and/or hypogynous cell in some 

species). Cystocarps are immersed in the outer medulla and are 

composed of branched gonimoblast filaments with terminal 

carposporangia, surrounded by a distinct pericarp of sterile filaments arising from the basal cell of the carpogonial branch. 

Carpospores are released through an ostiole at the thallus surface. Spermatangia are borne terminally on pigmented cortical 

filaments, scattered or in sori (i.e., Scinaia and Gloiophloea), or 

within small surface cavities in species of Nothogenia.

One genus of the family, Scinaia, is known from the northern Gulf of California.

Scinaia Bivona-Bernardi

Scinaia Bivona-Bernardi, 1822:232.

Ginannia Montagne, 1841:162, 200; Montagne, 1842a:257 [non Ginannia

Scopoli, 1777: 300].

Pseudoscinaia Setchell, 1914:119.

Pseudogloiophloea Levring, 1956:420.

Scinaia has a alternation of heteromorphic generations, a 

multiaxial gametophyte, and a sporophyte that is a tuft of uniseriate “Acrochaetium-like” filaments. The sporophytic phase is 

known only from culture studies on several species, one of them 

Scinaia confusa (Ramus, 1969, as Pseudogloiophloea confusa;

specimens cultured were from California). Thalli of gametophytes are erect, dichotomously to subdichotomously branched, 

rarely trichotomous or irregular, and attached to substratum by a 

small discoid holdfast. Gametophytes are multiaxial in structure 

and may be cartilaginous or soft but more or less turgid. Axes 

and branches may be terete to markedly compressed. Some species have regular or irregular constrictions at the nodes, whereas 

others are unconstricted. Internally, the medulla is loosely filamentous, with a central axis of longitudinally arranged filaments, which radiate dichotomously branched slender filaments 

that give rise to a cortex of several layers. The cortical filaments 

are slender, dichotomously branched, and composed of pigmented cells (hypodermal cells) many of which terminally bear 

larger, nearly colorless cells (utricles), a characteristic feature of 

this genus. The outermost cortical layer either is almost entirely 

composed of closely packed, laterally coherent inflated utricles 

that become pseudoparenchymatous (forming a continuous 

surface layer) or is a less consolidated mixture of inflated utricles or smaller utricles, with small pigmented cells interspersed 

around them, forming a rosette pattern in surface view. Slender 

rhizoidal-like filaments are periclinally aligned among and below 

the hypodermal cells.

Culture studies revealed monosporangia can be formed 

by both gametophytic and filamentous sporophytic phases for 

asexual reproduction (Ramus, 1969; Yoshizaki, 1993). Tetrasporophytes are branched uniseriate filaments, with irregularly 

zonate, cruciately, or decussately divided tetrasporangia terminal 

on branched filaments or sometimes displaced laterally by sympodial branching. Sometimes new sporangia proliferate within 

old sporangia. A crust presumed to be a sporophytic phase of 

Scinaia has also been reported (Le Gall and Saunders, 2010, as 

S. interrupta).

 Gametophytes are monoecious or dioecious. Carpogonial 

branches are three-celled, developing in the inner cortex. Prior 

to fertilization, the hypogynous cell produces two to four sterile branches (nutritive cells), and the basal cell initiates pericarp 

filaments. After presumed fertilization, gonimoblast filaments 

develop from the carpogonium (or from the hypogynous cell in 

some species; see Leon-Cisneros et al., 2009), and fusion cells are 

formed from the carpogonium, hypogynous cell, with or without 

the carpogonial branch basal cell, and basal cells of the gonimoblasts, and sterile branches on the hypogynous cell may also be 

incorporated. Cystocarps are immersed and have a dense, filamentous pericarp with a small pore at the thallus surface. Carposporangia are single and in opposite pairs or in chains on gonimoblast 

filaments. Spermatangial parent cells are elongate, on pigmented 

filaments interspersed among the utricles (in most species) or on 

the cortex. Clusters of terminal spermatangia form continuous or 

scattered superficial sori. The spermatangial sori of S. johnstoniae

cover the branch apices, giving them a cap-like appearance, and 

the utricles are absent from the cortex beneath the spermatangia.

Remarks. Regarding the generic relationship of Scinaia to Pseudoscinaia Setchell (1914), Huisman (1985) noted 

that Ramus’ (1969, as Pseudogloiophloea confusa) illustration 

of a cystocarp showed a loosely arranged gonimoblast similar to 

that of Pseudoscinaia snyderae (generitype) and concluded that 

their cystocarps were basically identical to those of the generitype 

of Scinaia (i.e., S. forcellata Bivona-Bernardi, 1822; =S. furcellata (Turner) J. Agardh, 1851; basionym: Ulva furcellata Turner, 

1801); therefore considering them to be congeneric. Although 

not known in Gulf of California, “Pseudoscinaia snyderiae” has 
NUMBER 96 • 6 9

been reported in Pacific Baja California from Bocana de Santo 

Tomas (R. Aguilar-Rosas and Aguilar-Rosas, 1986).

Four species of Scinaia are known in the Gulf of California, including Scinaia interrupta (A. P. de Candolle) M. J. Wynne 

(1989), which was recently reported in the southern Gulf (LeónCisneros et al., 2009). Three of these occur in the northern 

Gulf. Most often they are found in the cooler months of winter 

through spring.

KEY TO THE SPECIES OF SCINAIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Branches somewhat flattened, wide (5–10 mm in diameter); thalli branched in 1 plane; cystocarps primarily along margins (some may be scattered over thallus) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S. latifrons

1b. Branches terete (or sometimes slightly compressed), slender (mostly 2–5 mm in diameter); thalli branched in two planes; 

cystocarps scattered over thallus (not predominantly on margins) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Outer cortical layer in cross section of nearly colorless, obovoid utricles interspersed with numerous filaments of 2–3 

smaller pigmented cells; in surface view forming a rosette pattern; spermatangial branches scattered over branches, overtopping colorless utricles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S. confusa

2b. Outer cortical layer in cross section of nearly uninterrupted, colorless, square to oblong utricles (not interspersed with numerous filaments of pigmented cells); utricles polygonal in surface view, with an isolated pigmented cell occasionally among 

them; spermatangial branches forming cap-like sori over apices, without utricles beneath them . . . . . . . . . . S. johnstoniae

Scinaia confusa (Setchell) Huisman

FIGURE 32

Gloiophloea confusa Setchell, 1914:118, pl. 14: figs. 44–47; Kylin, 1941:6; 

Smith, 1944:190, pl. 42: fig. 1; Dawson, 1945d:37; Taylor, 1945:145; 

Dawson, 1953a:48, pl. 4: fig. 2; 1960a:36; Dawson et al., 1960a:64, 

pl. 16: fig. 5, pl. 17: fig. 4; Dawson, 1961b:406; 1962b:199, 229, figs. 

79, 80. 

Scinaia confusa (Setchell) Huisman, 1985:417, tbl. 1; Scagel et al., 1989:258; 

Stewart, 1991:67; Ramírez and Santelices, 1991:184; Anaya-Reyna and 

Riosmena-Rodríguez, 1996:864, tbl. 1; Pacheco-Ruíz and ZertucheGonzález, 2002:467; Y.-P. Lee and Ko, 2006:278, fig. 6; Y.-P. Lee, 

2008:222, figs. A–C; León-Cisneros et al., 2009:195, figs. 2–14, tbls. 

1–3; Bernecker, 2009:CD-Rom p. 61; Fernández-García et al., 2011:64. 

Pseudogloiophloea confusa (Setchell) Levring in Svedelius, 1956:13, fig. 8; 

Ramus, 1969:1–25, figs. 1–10, pls. 1–12; Norris and Abbott, 1972:90; 

Norris, 1973:9; Acleto O., 1973:20, figs. 43, 50; Abbott and Hollenberg, 1976:335, fig. 277; González-González et al., 1996:261; 

CONANP, 2002:141. 

Pseudogloiophloea confusa (Setchell) Hollenberg et I. A. Abbott, 1965:1178; 

Dawson, 1965:23; 1966a:14; Mateo-Cid et al., 2006:50.

Scinaia furcellata var. undulata sensu Farlow, 1875:367 [non Scinaia furcellata var. undulata (Montagne) J. Agardh, 1851:422, which is now Scinaia undulata (Montagne) Huisman, 1985:417].

Algae forming clumps, up to 15 cm tall, of several (rarely 

single) erect, semi-turgid, terete axes repeatedly dichotomously 

to subdichotomously branched, (4–)6–15 orders in 2 planes; 

branch dichotomies mostly at 2–7 mm intervals; rose red to 

dark red; attached by a small discoid holdfast. Branches slender, 

(1.0–)1.5–3.5(–5) mm in diameter; more or less uniform diameter throughout, without constrictions; branch apices narrowed, 

more or less acute or blunt tips. Medulla of loose filaments surrounding a more compact axial strand; medullary filaments radiate anticlinal branched slender filaments outward to the cortical 

layers. Inner cortex of 2–3 more or less ovoid cells, 9–12 μm in 

diameter (hypodermal cells); outward continuing with shorter 

filaments of 2–3 pigmented cells, 6–7 μm in diameter, that 

become interspersed among the larger, nearly colorless utricles of 

the outer layer. Rhizoid-like filaments aligned periclinally among 

and beneath hypodermal cell layer. Utricles in transverse section, 

spherical to obovate, mostly 20–30 μm tall, (15–)25–35 μm in 

diameter. In surface view, the rotund colorless utricles of various 

sizes surrounded by smaller pigmented cells gives a rosette appearance to the cortex.

Tetrasporophytes were found on “Acrochaetium-like” filaments in culture studies; sporophytes not yet identified in field. 

Gametophytes dioecious, sexual reproductive structures generally 

in the central portions of thalli. Cystocarps ovoid to pyriform, 

200–300 μm long and 200–250 μm wide, embedded in outer 

medulla (see León-Cisneros et al., 2009, for cystocarp development). Spermatangial branches composed of 2–4 elongate pigmented cells, arising from hypodermal cells, intermingled among 

the utricles, with clusters of spermatangia on thallus surface. 

Habitat. On rocks; low intertidal to subtidal, down 

to 15 m depths. 

Distribution. Gulf of California: Puerto Peñasco 

to Punta Los Frailes; Nayarit to Jalisco. Eastern Pacific: southern 

Alaska to Punta María, Baja California; Costa Rica; Peru; Galápagos Islands. Western Pacific: Korea.

Type Locality. Monterey, Monterey County, central California, USA (Smith, 1944:191).

Remarks. Tetrasporophytes were discovered to be 

“Acrochaetium-like” filaments in culture studies of S. confusa 

from California (see Ramus, 1969, as Pseudogloiophloea confusa), but this phase has not been found in nature. The central 

California Scinaia confusa and the southern California S. snyderae (Setchell) Huisman (1986; basionym: Pseudoscinaia 

snyderae Setchell, 1914) may be the same species (Abbott and 

Hollenberg, 1976; Huisman, 1985, 1986). Although S. snyderae was noted to be occasionally collected (Dawson, 1945d, 

as “P. snyderae”) or apparently rare (Abbott and Hollenberg, 

1976), according to Stewart (1991) it is known only from the 

original collection at Pacific Beach in San Diego. The taxonomic 
7 0 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

status and relationship of northern Gulf of California S. confusa

to type locality material of S. confusa and S. snyderae should be 

further investigated and genetically tested.

Scinaia johnstoniae Setchell

FIGURES 33, 34

Scinaia johnstoniae Setchell, 1914:97, pl. 11: figs. 14, 15; Setchell and 

Gardner, 1924:742; Dawson, 1944a:257; Taylor, 1945:147; Dawson, 

1945d:37; 1949b:237, 243; 1953a:44, pl. 3: fig. 12, pl. 21: fig. 1; Dawson et al., 1960a:80, pl. 17: fig. 5; Dawson, 1961b:406; 1962b:199, 

229, fig. 78; Norris, 1973:8; Acleto O., 1973:19, figs. 19, 48, 49; 

Abbott and Hollenberg, 1976:332, fig. 274; Ramírez and Santelices, 

1991:184; Stewart, 1991:68; Serviere-Zaragoza et al., 1993a:484; R. 

Aguilar-Rosas and Aguilar-Rosas, 1994:520; González-González et 

al., 1996:269; Anaya-Reyna and Riosmena-Rodríguez, 1996:864, tbl. 

1; L. Aguilar-Rosas et al., 2000:130; CONANP, 2002:141; PachecoRuíz and Zertuche-González, 2002:467; Riosmena-Rodríguez et al., 

2005b:34; R. Aguilar-Rosas et al., 2009:6, fig. 2d; León-Cisneros et 

al., 2009:200, figs. 28–43, tbls. 4–6; Bernecker, 2009:CD-Rom p. 61; 

Fernández-García et al., 2011:64.

Scinaia complanata sensu Taylor, 1945:146 [in part; non Scinaia complanata (Collins) Cotton, 1907:260; basionym: Scinaia furcellata

f. complanata Collins in Collins, Holden and Setchell, 1901a: P.B.-A. 

No. 836].

Scinaia furcellata var. undulata sensu Howe, 1911:502 [non Scinaia furcellata var. undulata (Montagne) J. Agardh, 1851:422; basionym: Ginnania undulata Montagne (1841) which is now Scinaia undulata (Montagne) Huisman, 1985:417].

Algae of 1 to a few erect, terete fronds, 6.0–23 cm tall, 

and dichotomously to subdichotomously branched in 2 planes, 

FIGURE 32. A–C. Scinaia confusa: A. Thin, terete, subdichotomously branched female gametophyte (JN-5302 A, US Alg. Coll.-217350). B. 

Transection of cortex with outermost layer of a mixture of pigmented filaments among colorless, somewhat round utricles. C. Surface view of 

cortex with rosette pattern of nearly colorless utricles encircled by rosette pattern of pigmented cells of various sizes and shapes (B, C, JN-5024, 

US Alg. Coll. microscope slide 4247). 
NUMBER 96 • 7 1

FIGURE 33. Scinaia johnstoniae: A. Habit of male gametophyte with dense spermatangia covering some apices forming darker cap-like 

sori (JN-5670, US Alg. Coll.-217351). B. Branch with darker cap-like spermatangial sori on some apices (JN-5670, US Alg. Coll.-160916). 

C. Smaller thallus to show morphological variation (JN-5023, US Alg. Coll.-160907). 
7 2 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

6–8(–10) orders at 2.0–12 mm intervals; attached by a small 

discoid holdfast. Branches without constrictions; 3.5–5.0 mm in 

diameter in upper portions, with acute to blunt apices; becoming 

narrower proximally (downward), to 1.0–2.0 mm in diameter. 

Internally composed of a thin central axis of compact longitudinal aligned filaments that radiate out into loose dichotomously 

branched medullary filaments that ultimately produce the cortical filaments. Cortex differentiated into two sections; inner 

cortical layers of pigmented spherical to pear-shaped cells (hypodermal cells, 10–18 μm in diameter) and an outer layer of larger, 

nearly colorless utricles forming a continuous surface layer. Utricles in transection, squarish to oblong and slightly taller than 

wide, 18–30 μm length, 17–25 μm wide; in surface view, utricles 

polygonal, of similar size, with an occasional, small pigmented 

cell interspersed among them.

Tetrasporophytes not known. Gametophytes monoecious or 

dioecious. Cystocarps embedded in outer medulla, about (140–

)160–220 μm in diameter; scattered throughout central portion 

of thallus. The cap-like spermatangial sori (“apical cap type” 

of Kajimura, 1988) densely cover the surface of branch apices 

and are easily noticed because of the difference in color. Cortical 

utricles are absent beneath the sori. Spermatangial branches a 

mixture of smaller cells arising from hypodermal cells (similar to 

those of the California S. articulata Setchell (1914; cf. Dawson, 

1949b:23, pl.7: figs. 44, 45).

Habitat. Growing on rocks and various other substrata, often in shell and sand bottoms and sometimes partially 

sand covered; subtidal, down to 20 m depths.

Distribution. Gulf of California: El Coloradito to 

Punta Los Frailes; laguna, Santa María-La Reforma; Sinaloa to 

Jalisco; Islas Marías (Islas Tres Marías). Eastern Pacific: southern California to Bahía de Ballenas, Baja California Sur; Islas 

Los Coronados (off northern Baja California); Costa Rica; Peru; 

Galápagos Islands.

Type Locality. San Pedro, Los Angeles County, 

southern California, USA.

Remarks. Scinaia johnstoniae is a cylindrical species, 

with an outer cortex of utricles that tend to flatten on their outer 

(distal) end. Dawson (1953a:48) suggested Scinaia minima E. Y. 

Dawson (1945a:103; type locality: off Isla Cedros, Pacific Baja 

California) may prove to be a dwarfed form of S. johnstoniae. 

Similar cap-like spermatangial sori are found in the southern California S. articulata Setchell (1914; cf. Dawson, 1949b:23, pl.7: 

figs. 44, 45; type locality: Santa Barbara), but S. johnstoniae does 

not have the characteristic constricted segments of S. articulata. 

Known from the type locality and Santa Barbara Island (California Channel Islands; Dawson, 1949b, 1961b), S. articulata has 

also been reported to the south from Cabo Colonet (Colnett), 

Pacific Baja California (R. Aguilar-Rosas and Aguilar-Rosas, 

1986). Although León-Cisneros et al. (2009) recently considered 

S. articulata conspecific with S. johnstoniae, their relationship 

should additionally be elucidated by molecular testing.

Gulf Scinaia johnstoniae is also similar to the Japanese 

S. tokidae Kajimura (1988, type locality: off Tsudo, Oki Islands). Scinaia tokidae has branches that are not constricted, 

but it branches in three planes, with 5–11 branch dichotomies, 

and has slightly pigmented, larger rounded to oval utricles. Gulf 

S. johnstoniae somewhat resembles S. japonica Setchell (1914; 

type locality: Misaki, Kanagawa Prefecture), but it differs primarily in being smaller, lacks constricted segments, has fewer 

FIGURE 34. Scinaia johnstoniae: A. Surface view of cortex with laterally cohering utricles forming polygonal pattern with isolated pigmented 

cells. B. Transection with outermost cortical layer of nearly colorless abutting utricles above a layer of pigmented hypodermal cells that are connected to medullary filaments, and rhizoidal filaments (A, B, JN-5023, US Alg. Coll. microscope slide 4301). 
NUMBER 96 • 7 3

branch dichotomies (mostly 6–8), branches in two planes, and, 

in transection, utricles are squarish to oblong (only slightly taller 

than wide), whereas S. japonica has constricted segments, 9–11 

branch dichotomies, and elongated utricles (in transection) [note: 

see comments of Y.-P. Lee and Ko, 2006:280 on taxonomic status of S. japonica]. The taxonomic distinction and molecular 

phylogenetic relationship of the nonconstricted S. johnstoniae, S. 

japonica (Kaneko, 1975:9, figs. 2–11), S. minima, and S. tokidae,

and the constricted S. articulata needs to be further investigated.

Scinaia latifrons M. Howe

FIGURE 35

Scinaia latifrons M. Howe, 1911:500, fig. 1, pl. 28 (type); Setchell, 

1914:102, pl. 11: fig. 23; Setchell and Gardner, 1924:742; Dawson, 1944a:258; Taylor, 1945:148; Dawson, 1945d:37; 1949c:237; 

1953a:46, pl. 4: fig. 1; 1960a:36; 1961b:406; 1962b:229; Norris, 

1973:9; Acleto O., 1973:18, figs. 41, 44–47; Abbott and Hollenberg, 

1976:332, fig. 275; Ramírez and Santelices, 1991:184; Kajimura, 

1995:540, fig. 19; González-González et al., 1996:270; Yoshida, 

1998:506; CONANP, 2002:141; Pacheco-Ruíz and ZertucheGonzález, 2002:467; León-Cisneros and Riosmena-Rodriguez, 

2005:31, fig.1; Riosmena-Rodríguez et al., 2005b:34; Bernecker and 

Wehrtmann, 2009:226; León-Cisneros et al., 2009:203, figs. 44–60, 

tbls. 7–9; Fernández-García et al., 2011:64.

Gametophytes erect, flattened, unconstricted, subdichotomously branched in 1 plane, and up to 22 cm tall; above a short, 

terete stipe (2–5 mm long); attached by a small discoid holdfast. 

Branch segments 5–10(–12) mm wide, 1.3–3.0 cm long. Internally, a distinct central axial strand is absent, medullary filaments branch outward, ultimately forming cortical layers of 1–2 

small, globose, pigmented cells, 18–20 μm in diameter, beneath 

an outer surface layer of larger, nearly colorless, closely abutting 

oblong to square utricles, 33–45 μm tall by 18–30 μm wide in 

transverse view. In surface view, utricles polygonal, with a minute pigmented cell occasionally among them.

Tetrasporophyte not known. Gametophytes dioecious (Kajimura, 1995). Cystocarps, spherical to pyriform, (200–)320–

375 μm in diameter; embedded within the outer medulla and 

scattered but aggregated most abundantly along thallus margins. 

Spermatangia in elongate sori continuous along margins from 

base to upper thallus, except the apices and axils (“marginal belt 

type” of Kajimura, 1995). Spermatangial branches 2–3 elongated 

FIGURE 35. Scinaia latifrons: Habit of female gametophyte showing flattened wide axes with the 

majority of cystocarps along lateral margins, some scattered (JN-5049, US Alg. Coll.-160925). 
7 4 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

cells arising from hypodermal cells, inserted among the utricles, 

with terminal spermatangia at frond surface.

Habitat. Growing on rocks or hard substratum, 

which are often partially sand covered, or on shell and sand bottoms; subtidal, from 5 to 22.7 m depths.

Distribution. Gulf of California: Punta Pelicano 

(vicinity of Puerto Peñasco) to Guaymas; Isla Willard (Bahía 

San Luis Gonzága) to Punta Períco (Baja California Sur); Puerto 

Refugio, Isla Ángel de la Guarda. Eastern Pacific: California 

Channel Islands to Oaxaca; Costa Rica; Peru; Galápagos Islands.

Type Locality. Near La Paz, Baja California Sur, 

Gulf of California, Mexico.

Remarks. Scinaia latifrons is similar to the western Pacific S. cottonii Setchell (1914) (Okamura, 1921; Tseng, 

1941; Dawson, 1953a). Although Yoshida (1998, as S. latifrons) 

considered them conspecific, León-Cisneros and RiosmenaRodríguez (2005) suggested this synonymy not be followed, and 

others have also kept them separate (e.g., Tseng, 1983; Kajimura, 

1995; Y.-P. Lee and Ko, 2006; Y.-P. Lee, 2008).

Kajimura (1995) supported Dawson’s (1953a) observation that the most apparent distinction between these two 

may be the location of the spermatangial sori. Gulf S. latifrons

had spermatangial sori along the entire margin from base to 

top except for the apices and axils (marginal-belt-type of Kajimura, 1995:540, fig. 19), and the Japanese S. cottonii had 

spermatangia in small, scattered, irregularly shaped sori on the 

frond surface (“irregular-type” of Kajimura, 1988; 1995:536, 

fig. 18). Kajimura (1995) further characterized S. latifrons to be 

dioecious, with cystocarps (320–375 μm in diameter), utricles 

elongated in tranverse view (33–45 μm tall by 18–29 μm in diameter), and 1–2 cortical layers of cells (18–20 μm in diameter); 

and S. cottonii to be monoecious, have larger cystocarps (up to 

482 μm in diameter), utricles square, roundish, or elongate (26–

40 μm by 21–40 μm), and a thicker cortex of 2–3(–4) layers of 

smaller cells (5–10 μm in diameter). In an expanded definition, 

León-Cisneros et al. (2009) reported S. latifrons to be monoecious, described cystocarp development with a new pattern of 

fusion cell development involving adjacent cells of the basal cell, 

observed spermatangia in marginal belts, and added they were 

also scattered throughout the thallus. Gulf specimens exhibiting these characters should be tested by molecular analyses and 

compared to S. latifrons sensu stricto as well as S. cottonii. 

Palmariales

Palmariales Guiry et D. E. G. Irvine in Guiry, 1978b:138.

Algae are of various forms, including filamentous, thin 

prostrate crusts of laterally fused filaments and narrow to wide 

fronds. Gametangial thalli are monoecious or dioecious. Some 

species have spermatangial and tetrasporangial thalli of similar 

morphologies. Some have both carpogonia and spermatia on the 

same thallus.

Life history is diphasic. There is an absence of a carposporophyte in the life history. A single-cell carpogonium is developed 

in much smaller carpogonial thalli, and a tetrasporangial thallus 

is developed directly from a fertilized carpogonium, overgrowing the carpogonial thallus. Tetrasporangia are repeatedly regenerated from a basal generative stalk cell (unique to the order). 

Monosporangia are not known. Pit plug ultrastructure shows a 

two-cap membrane.

Remarks. Ragan et al. (1994), on the basis of 

their molecular analysis, found that rDNA SSU (small-subunit 

ribosomal DNA) data of some morphologically different 

taxa of the Acrochaetiales were related to members of the 

Palmariales. 

At present the Palmariales is composed of four families, one 

of which is reported in the northern Gulf of California.

Rhodophysemataceae

Rhodophysemataceae G. W. Saunders et J. McLachlan. 1990:20; Saunders 

and McLachlan, 1991:272.

Filamentous algae, composed of erect and prostrate uniseriate filaments that attach to substratum or algal host by laterally 

fused cells that form a compact monostratic base. Erect filaments 

develop individually or in clusters and may become adherent and 

pseudoparenchymatous, resulting from cell fusions or mucilaginous envelopes or a combination of both. Cells contain either 

a parietal or ribbon-shaped chloroplast or numerous discoid 

chloroplasts and lack pyrenoids. The pigment B-phycoerythrin 

is present. Ultrastructure reveals a two-cap layer (Pueschel and 

Cole, 1982).

Gametophytes are monoecious with sessile carpogonia and 

paired spermatangia. After presumed fertilization, the carpogonium gives rise directly to a tetrasporangium that is subtended 

by a stalk cell.

Remarks. Pueschel and Cole (1982) reported that 

Rhodophysema Batters (1900) had the same kind of pit plugs as 

members of the Palmariales. DeCew and West (1982) found the 

Rhodophysema crusts to be a gametangial, with both carpogonia and spermatangia, and its sexual life history was anomalus. 

The fertilized carpogonium divides into a stalk cell and a tetrasporangium (the stalk cell can produce successive tetrasporangia), and DeCew and West (1982) suggested the genus belongs 

in the Palmariales.

The Rhodophysemataceae, on the basis of Rhodophysema, 

was described by Saunders and McLachlan (1990). Saunders et 

al. (1995) and Clayden and Saunders (2010) confirmed the earlier suggestion of Saunders and McLachlan (1990, 1991) that 

the family belongs in the Palmariales. Members of the family 

do not produce monosporangia, lack a carposporophyte phase 

in their life histories, and are characterized by the presence of 

the pigment B-phycoerythrin. These characters separate Rhodophysemataceae from the Palmariaceae Guiry (1974), which has 

tetrasporophyte and carposporophyte phases and the pigment 

R-phycoerythrin.

Currently, five genera are recognized in the family. One—

the recently described genus Rhodonematella—was tentatively 
NUMBER 96 • 7 5

placed in the family (Clayden and Saunders, 2010) and is now 

reported in the northern Gulf of California.

Rhodonematella Clayden et G. W. Saunders

Rhodonematella Clayden et G. W. Saunders, 2010:297, figs. 7–11.

Algae are microscopic to minute gametophytes; composed 

of uniseriate, simple to branched erect filaments and prostrate, 

sometimes branched, basal filaments. Cells of basal and erect filaments usually have one parietal chloroplast and are without pyrenoids. The filamentous gametophytes are composed of a basal 

system of endophytic cells that are “immersed” in the host cortex 

(but apparently not penetrating host cortical cells) and an erect 

system of free one- to three-celled filaments that arise directly 

from the basal cells.

Monoecious filaments have both sessile carpogonia and 

spermatangia on one- to two-celled erect filaments. Following 

presumed syngamy, the carpogonia directly gives rise to diminutive, moderately branched, filamentous tetrasporophyte. Tetrasporangia, produced directly from the fertilized carpogonium, 

are cruciately divided, borne terminally on the filaments, and 

surrounded by presumed gametophytic, multicelled filaments 

(paraphyses) (reproduction after Clayden and Saunders, 2010).

Remarks. Rhodonematella is most easily confused 

with some members of Rhodochorton Nägeli (1862). Although 

both genera lack pyrenoids and monosporangia, the marine species of Rhodochorton reproduce asexually by tetrasporangia and 

have stellate plastids (Y.-P. Lee and Lee, 1988; Harper and Saunders, 2002). In contrast, Rhodonematella has gametangial thalli 

in which the carpogonia directly produces a terminal cruciate 

tetrasporangium and has cells with a single parietal plastid (Y.-P. 

Lee and Kurogi, 1978; Garbary et al., 1983).

Although both genera are found in the intertidal to shallow subtidal of temperate to subtropical seas, Rhodonematella 

subimmersa is an endo-epiphyte on its foliose red algal hosts, 

e.g., species of Halymenia, Grateloupia, and Kallymenia, 

whereas most species of Rhodochorton grow on rocks or other 

hard substratum. The life histories of Rhodochorton subimmersum and R. floridulum (Dillwyn) Feldmann (in Christensen, 

1978; basionym: Conferva floridula Dillwyn, 1809; generitype of 

Rhodonematella) (Y.-P. Lee and Kurogi, 1978; Stegenga, 1978, 

1979) were reinterpreted by Clayden and Saunders (2010), who 

recognized Rhodonematella and tentatively placed it in the 

Rhodophysemataceae.

Rhodonematella is represented by a single species in the 

northern Gulf of California.

Rhodonematella subimmersa (Setchell et N. L. Gardner) 

Clayden et G. W. Saunders

Rhodochorton subimmersum Setchell et N. L. Gardner, 1903:347, pl. 17: 

fig. 12; Kylin, 1925:45; Drew, 1928:191, pl. 47: fig. 81; Nakamura, 

1941:290, fig. 17; Smith, 1944:185; Y.-P. Lee and Kurogi, 1978:115, 

figs. 1–10; Y.-P. Lee, 1987:45, fig. 22A–H; Y.-P. Lee and Yoshida, 

1997:206; Yoshida, 1998:472; Y.-P. Lee, 2008:178, figs. A–C. 

Rhodonematella subimmersa (Setchell et N. L. Gardner) Clayden et G. W. 

Saunders, 2010:297, figs. 7–11.

Acrochaetium subimmersum (Setchell et N. L. Gardner) Papenfuss, 

1945:318; Dawson, 1961b:404; Hollenberg and Abbott, 1966:42; Abbott and Hollenberg, 1976:319, fig. 261; Silva, 1979:317; Josselyn and 

West, 1985:143; González-González et al., 1996:167; Pacheco-Ruíz et 

al., 2008:206. 

Audouinella subimmersa (Setchell et N. L. Gardner) Garbary et Rueness, 

1980:22; Garbary et al., 1983:56, fig. 23; Garbary, 1987:178; Scagel et 

al., 1989:151; Hansen, 1997:5.

Colaconema subimmersum (Setchell et N. L. Gardner) P. W. Gabrielson in 

Gabrielson et al., 2004:95.

Algae filamentous; endo-epiphytic, forming dark red to reddish patches on algal host; of short, erect filaments protruding 

above surface, attached by basal filaments on host surface with 

endophytic filaments immersed between cortical cells of host. 

Basal endophytic filaments, unbranched or sometimes branched; 

of irregularly shaped elongated cells, (15–)25–40(–50) μm long 

and 4.0–6.0 μm wide. Erect filaments (above host surface), short, 

simple, or occasionally branched above, usually not more than 

2–6(–10) cells tall; of cells mostly about as long as wide to oblong, 4.0–7.0 μm long, 3.0–6.0 μm in diameter. Cells with a single parietal chloroplast and without pyrenoids.

Tetrasporangial thalli filamentous, developed directly from 

fertilized carpogonium; tetrasporangium on a stalk cell, borne 

lateral and terminal on erect filaments, cruciately divided, ellipsoid, 15–21 μm long, 10–13 μm wide. Carpogonial and 

spermatangial thalli filamentous, monoecious (as reported elsewhere). Carpogonium “flask shaped,” 5–10 μm long and 3–4 

μm wide, with a terminal trichogyne, up to 8.0 μm long, 2.0–3.0 

μm in diameter; sessile on a single basal cell, on 1- to 3-celled, 

erect filaments. Presumably fertilized carpogonium divides transversely and develops simple to branched gonimoblast filaments 

that bear a terminal, cruciate tetrasporangia. Spermatangial parent cell develops a single, globose spermatangium lateral on cells 

of creeping prostrate filaments and terminal on short erect filaments; spermatia 3–4 μm in diameter (reproduction after Y.-P. 

Lee and Kurogi, 1978; Y.-P. Lee and Yoshida, 1997; Clayden and 

Saunders, 2010). 

Habitat. An endo-epiphyte found growing within 

the cortical layer and partially on the surface of Halymenia californica and Kallymenia pertusa; shallow subtidal, down to 10 m 

depths.

Distribution. Gulf of California: Isla San Esteban. 

Eastern Pacific: southern British Columbia to California Channel 

Islands (off southern California). Western Pacific: Japan; Korea.

Type Locality. Endo-epiphyte on Grateloupia 

doryphora; Whidbey Island (Whidby), Island County, Puget 

Sound, Washington, USA.

Remarks. A new record for the Gulf of California,

Rhodonematella subimmersa was found growing in Halymenia californica (JN-5540, US Alg. Coll. microscope slide 4243) 

and Kallymenia pertusa (JN-5538, US Alg. Coll. microscope 

slide 4262), off the southern end of Isla San Esteban. The Gulf 
7 6 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

specimens referred to R. subimmersa mostly closely resemble 

those of Abbott and Hollenberg (1976: fig. 261, as Acrochaetium subimmersum). Previously known on the Pacific coast of 

North America, R. subimmersa has been found growing, in addition to Halymenia, on Grateloupia, Prionitis, and Schizymenia 

(Abbott and Hollenberg, 1976) and should be looked for on the 

Gulf species of these genera as well.

CORALLINOPHYCIDAE

Corallinophycidae L. Le Gall et G. W. Saunders, 2007:1129.

A large group of articulated and nonarticulated calcified 

algae, with calcification in the form of calcite. Members are characterized by pit plugs that have two cap layers, and the outer 

pit plug is dome shaped. Tetrasporophytes, where known, produce zonately or cruciately divided tetrasporangia. Carpogonial 

branches are two-celled.

Remarks. Coralline algae are ecologically important 

and widespread in distribution from polar regions to the tropics. 

They are critical, often predominant components of intertidal 

to deep subtidal marine ecosystems and are the deepest known 

plants on earth (Littler et al., 1985, 1986). Studies of global and 

climate changes have shown coralline algae to be vulnerable to 

environmental changes such as warming and ocean acidification 

(Nelson, 2009; Díaz-Pulido et al. 2012; Nash et al., 2012; Teichert et al., 2012). Coralline algae and their habitats will require 

further studies and long-term ecological monitoring.

There are three orders currently recognized in the subclass 

Corallinophycidae: the Corallinales; Rhodogorgonales Fredericq, 

J. N. Norris, et Pueschel (in Fredericq and Norris, 1995); and the 

Sporolithales L. Le Gall, Payri, Bittner et G. W. Saunders (2010).

One order, the Corallinales, is well represented in the northern Gulf of California.

Corallinales*

Corallinales P. C. Silva et Johansen, 1986:250.

The Corallinales are considerably varied in shape and size 

and include pink to purple calcified algae that may be growing 

attached to various substrates, unattached and free-living, or 

partly endophytic in other corallines. Members are either (1) nonarticulated, crustose, and prostrate, (2) articulated (jointed) and 

erect, or (3) partially endophytic. The nonarticulated, crustose 

corallines are smooth, warty, or with protuberances and usually 

spreading. Some apparently may break away from the rocky or 

hard substrata, with the crustose fragments continuing to grow 

or possibly attaching to calcium carbonate particles or mollusk 

shell fragments, eventually surrounding them to form rhodoliths 

(e.g., Foster et al., 1997; Riosmena-Rodríguez et al., 2010) or 

* Contributed by James N. Norris and H. William Johansen. H. W. 

Johansen: Department of Biology, Clark University, Worcester, 

Massachusetts 01610, USA.

maërl (e.g., Blunden et al., 1997; Foster, 2001; Hinojosa-Arango 

et al., 2009). Rhodoliths remain unattached as free-living, subspherical to irregular-shaped nodules that may be smooth or 

with protuberances or branches. The other major group, the articulated or jointed species have erect parts or fronds consisting 

of calcified segments (intergenicula) that are separated by flexible, uncalcified joints (genicula). These articulated fronds are attached to rocks, shells, or other algae by holdfasts of thin crusts 

or of entangled, segmented rhizomes.

Living rhodolith or maerl (maërl) beds are unique marine 

ecosystems worldwide. An individual rhodolith may be a single 

species, but sometimes a rhodolith may be composed of multiple 

species. Rhodolith beds, although disjunct in distribution, are 

particularly abundant in the Pacific from the Gulf of California and southern Japan; the Eastern Atlantic coasts of Norway, 

Ireland, and Scotland; the Mediterranean Sea and Red Sea; the 

Western Atlantic coasts of northeast Canada, Caribbean Sea, 

and Brazil; and the Indian Ocean and southern ocean coasts of 

western Australia (Foster, 2001; Amado-Filho et al., 2012). Rhodoliths were known as “chicaron” on the former pearl-fishing 

banks around La Paz (Dawson, 1944a). In the Gulf of California, rhodolith beds are often extensive, occuring from Puerto 

Peñasco to Islas Marietas off Nayarit (Foster et al., 1997; YaburPacheco and Riosmena-Rodriguez, 2006; Riosmena-Rodríguez 

et al., 2010: fig. 3.1). With their high ecological and economic 

value they are now recognized as critical habitats in need of 

monitoring and conservation (Ávila and Riosmena-Rodríguez, 

2010; Riosmena-Rodríguez et al., 2010). 

The internal structure of most coralline algae is pseudoparenchymatous, composed of delicate filaments cemented together 

by cell walls impregnated with calcium carbonate in the mineral 

form of calcite. Meristematic cells are intercalary and produce 

epithallial cells outward and other vegetative cells inward. Cells 

of the contiguous vegetative filaments can be united by fusions 

or by direct secondary pit connections, and trichocytes may be 

either present or absent. Ultrastructure of those studied thus far 

shows the primary pit plugs have two cap layers, with the outer 

cap layer dome-shaped (Pueschel and Cole, 1982; Pueschel, 

1987, 1989). Internally the fronds of articulated coralline algae 

are composed of a central core of filaments, the medulla, and 

the surrounding pigmented tissue of the cortex. The crustose 

corallines are composed of three tissue layers of filaments: (1) a 

hypothallium, in which the filaments are close to the substrate 

and more or less parallel to it; (2) a perithallium, in which the 

filaments are above the hypothallium and more or less perpendicular to the substratum; and (3) an epithallium, the upper or 

superficial layer of cells that in many may regularly slough off. 

In some species epithallial cells are rarely seen, in others they can 

build up to several layers, and in a few they give rise to a significant photosynthetic tissue.

Although vegetative reproduction by fragmentation has 

been assumed in rhodolith species, Schaeffer et al. (2002) found 

no genetic evidence of cloning among Gulf of California species they investigated.Tetrasporangia or bisporangia are borne 
NUMBER 96 • 7 7

within conceptacles with large red bisporangia or zonately 

divided tetrasporangia (Corallinaceae). In some genera, conceptacles are developed with a uniporate opening. In others, 

sporangia develop thick cap walls (“beak”) that eventually 

break out, giving rise to conceptacles that are multiporate (Hapalidiaceae subfam. Melobesioideae, e.g., Lithothamnion) with 

one pore for each sporangium. For some, asexual reproduction 

may also be by means of thallus fragmentation, apomeiotic 

bispores, or propagules. Gametangial thalli may be monoecious 

or dioecious, with gametangia always produced within uniporate conceptacles located on the surfaces of crustose (nonarticulated) species and either in the surface or apices of the calcified 

segments (intergenicula) of the articulated species. Carpogonial 

conceptacles bear supporting (auxiliary) cells on the floor, each 

with one to two two-celled carpogonial filaments in which the 

trichogynes project through the pore at maturity. After fertilization the auxiliary and associated cells irregularly or sometimes 

completely fuse to form a more or less flat fusion cell. Short gonimoblast filaments grow from the margins or upper surface of a 

fusion cell, forming large red carposporangia, each containing a 

single carpospore. Spermatangial conceptacles contain simple to 

dendroid spermatangial filaments either on the conceptacle floor 

and/or sometimes along the conceptacle walls and roof that produce spermatangia.

The Corallinales as currently interpreted comprise two families, the Corallinaceae J. V. Lamouroux (1812) and Hapalidiaceae J. E. Gray (1865). The family Sporolithaceae Verheij (1993), 

previously considered to belong to the Corallinales, has been recognized to be a new order, the Sporolithales L. Le Gall, Payri, 

Bittner et G. W. Saunders (Le Gall et al., 2010), supported by 

molecular evidence and the morphological studies of Townsend 

et al. (1995) of Sporolithon Heydrich (1897b).

Terminology and characters, along with illustrations, unique 

to members of the Corallinales are elucidated in Johansen (1981), 

Woelkerling (1988), Irvine and Chamberlain (1994), Womersley 

(1996), Keats (n.d. [accessed 2010]), and Rasser (2010).

The two families of the Corallinales are represented in the 

northern Gulf of California.

KEY TO THE FAMILIES OF THE CORALLINALES IN THE NORTHERN GULF OF CALIFORNIA

1a. Sporangial conceptacles uniporate; bisporangia and tetrasporangia do not produce apical plugs . . . . . . . Corallinaceae

1b. Sporangial conceptacles multiporate; bisporangia and tetrasporangia produce apical plugs at pore . . . . . Hapalidiaceae

Corallinaceae

Corallinaceae J. V. Lamouroux, 1812:185.

The Corallinaceae is separated from the other families primarily by the manner of sori development and characters of 

tetrasporangia and bisporangia. In the Corallinaceae, tetrasporangia and bisporangia are borne in conceptacles (interpreted as 

modified sori) with calcified roofs and may be somewhat sunken, 

more or less level, or protruding from the thallus surface. The 

tetrasporangia are simultaneously cleaved and zonately divided 

and are not developed below multiporate plates, and they are not 

individually within calcified compartments (see Townsend et al., 

1995; A. Harvey et al., 2003b).

Remarks. Articulated and crustose coralline algal 

species of the Corallinaceae are prominent in the Gulf of California and include species from seven of the subfamilies. The articulated species reported from the northern Gulf are members are 

in two subfamilies: C. subfam. Corallinoideae, which includes 

Corallina, Haliptilon, and Jania, and C. subfam. Amphiroideae, 

with Amphiroa.

The Corallinaceae are widespread and ecologically important in the Gulf of California, with 55 species; 31 nonarticulated 

(crustose) coralline species in 17 genera, 23 articulated species in 

4 genera, and 1 parasitic genus.

KEY TO THE SUBFAMILIES OF THE CORALLINACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli geniculate; branches composed of uncalcified genicula (joints) and calcified intergenicula (calcified segments 

between uncalcified joints) (articulated corallines) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

1b. Thalli nongeniculate; either without branches or with solid calcified branches not composed of genicula and intergenicula 

(nonarticulated corallines) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2a. Articulated branches with uncalcified genicula of 1 to several tiers of cells; secondary pit connections present; cell fusions 

absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. subfam. Amphiroideae

2b. Articulated branches with genicula of 1 tier of cells; secondary pit connections absent; cell fusions present . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. subfam. Corallinoideae

3a. Some cells of vegetative filaments linked by secondary pit connections; cell fusions absent or very rare . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. subfam. Lithophylloideae

3b. Some cells of vegetative filaments linked by cell fusions; secondary pit connections absent or very rare . . . . . . . . . . . . 4

4a. Spermatangial filaments develop on conceptacle chamber floor, walls, and roof . . . . . . C. subfam. Neogoniolithoideae

4b. Spermatangial filaments developed only on conceptacle chamber floor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
7 8 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

5a. Trichocytes present in large tightly packed horizontal rows without vegetative filaments between them . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. subfam. Porolithoideae

5b. Trichocytes absent or present; if present, solitary, in pairs, or in small groups or rows with vegetative filaments between 

them (not in large tightly packed horizontal rows) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6a. Gulf of California members primarily dimerous in thallus construction; sporangial conceptacle pore canal lined by cells 

oriented more or less perpendicular to conceptacle roof and that do not protrude into pore canal . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. subfam. Hydrolithoideae

6b. Gulf of California members monomerous or dimerous in thallus construction; sporangial conceptacle pore canal lined by 

cells oriented more or less parallel to conceptacle roof and that protrude laterally into pore canal . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. subfam. Mastophoroideae

KEY TO THE GENERA OF CORALLINACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Nonarticulated calcified crustose algae, consisting of crusts or nodules (rhodoliths); with protuberances or branches 

without flexible noncalcified joints, or without protuberances; nonarticulated Corallinaceae . . . . . . . . . . . . . . . . . . . . 2

1b. Articulated calcified algae, composed of flexible fronds of calcified segments (intergenicula) that are separated by noncalcified joints (genicula); articulated Corallinaceae . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

2a. Semiendophytic minute, parasite on articulated corallines; lateral cells of adjacent filaments not linked (no secondary pit 

connections nor cell fusions) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Choreonema 

2b. Not semiendophytic or parasitic, larger; with some form of lateral cell linkage (secondary pit connections and/or cell 

fusions) between cells of adjacent filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

3a. Secondary pit connections link some cells of adjacent filaments; cell fusions absent or rare . . . . . . . . . . . . . . . . . . . . . 4

3b. Cell fusions link some cells of adjacent filaments; secondary pit connections absent or rare . . . . . . . . . . . . . . . . . . . . . 6

4a. Primigenous (basal) filaments of palisade cells (vertically elongated cells) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4b. Primigenous (basal) filaments of nonpalisade cells (quadrate or squarish cells) . . . . . . . . . . . . . . . . . . . . . Lithophyllum

5a. Crusts very thin, usually a single cell layer; overgrowing each other (up to 4 layers) . . . . . . . . . . . . . . . . . . . Litholepis

5b. Crusts thicker, of 2 or more cells layers thick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Titanoderma

6a. Tetrasporangial and bisporangial conceptacles uniporate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6b. Tetrasporangial and bisporangial conceptacles multiporate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

7a. Thallus construction either dimerous or monomerous; or both monomerous and dimerous . . . . . . . . . . . . . . . . . . . . . 8

7b. Thallus construction primarily dimerous (protuberances, if present, may be radially arranged and monomerous) . . . . . 11

8a. Thallus construction primarily monomerous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

8b. Thallus construction both monomerous and dimerous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spongites (in part)

9a. Spermatangial filaments arise from spermatangial chamber floor, walls, and roof . . . . . . . . . . . . . . . . . Neogoniolithon

9b. Spermatangial filaments arise only from spermatangial chamber floor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

10a. Trichocytes tightly packed in large horizontal fields . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Porolithon

10b. Trichocytes, if present not as above, not tightly packed, usually with vegetative cells between trichocytes; if trichocytes in 

horizontal rows, in smaller groups (rows shorter) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spongites (in part)

11a. Crusts thin, usually less than 200 μm thick, without protuberances; often epiphytic, not forming free living rhodoliths 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

11b. Crusts thicker, usually greater than 200 μm thick, may have protuberances; on rocks, epiphytic or may form free living 

rhodoliths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

12a. Sporangial conceptacle pore canal in vertical section lined with cells parallel to roof that protrude into pore canal; trichocytes not observed in primigenous (basal) filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spongites (in part)

12b. Sporangial conceptacle pore canal in vertical section lined with cells perpendicular to roof surface that do not protrude 

into pore canal; trichocytes terminal on primigenous filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydrolithon (in part)

13a. Trichocytes absent ; crusts epiphytic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Heteroderma

13b. Trichocytes present or absent; on rocks or epiphytic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

14a. Trichocytes when present, intercalary within primigenous (basal) filaments or terminal on postigenous (erect) filaments; 

pore canal of sporangial conceptacles (in vertical section) lined, at least initially, by horizontally oriented cells (parallel to 

conceptacle roof surface); germination disc with 8-celled center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pneophyllum

14b. Trichocytes, when present, terminal on primigenous filaments or intercalary on postigenous filaments; pore canal of sporangial conceptacles (in vertical section) lined by enlarged, vertically oriented cells (perpendicular to conceptacle roof); 

germination disc with 4-celled center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
NUMBER 96 • 7 9

15a. Crusts not extensively overlapping each other; sporangial conceptacles 200–225 μm in diameter . . . . . Fosliella? paschalis 

15b. Crusts often overlapping each other; sporangial conceptacles smaller, 100–160 μm in diameter . . . . Hydrolithon (in part)

16a. Thallus construction dimerous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Melobesia 

16b. Thallus construction monomerous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

17a. Epithallial cells flattened and flared at corners; monomerous core of filaments noncoaxial . . . . . . . . . . . Lithothamnion 

17b. Epithallial cells not flared; monomerous core of filaments coaxial . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mesophyllum

18a. Genicula of 2 or more medullary cell tiers (one species, A. valonioides, has 1 tier); medullary cell tiers in the intergenicular 

segments of differing heights; conceptacles on surfaces of segments; secondary pit connections present between some cells 

of adjacent filaments; cell fusions absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amphiroa

18b. Genicula a single tier of thick-walled medullary cells; medullary cell tiers in the intergenicular segments all the same height; 

conceptacles mostly in the apices of fertile segments; secondary pit connections absent; cell fusions present between some 

cells of adjacent filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

19a. Primarily dichotomously branched; terete to subterete segments (intergenicula) less than 300 μm in diameter; intergenicula mostly of 3–6 tiers of cells holdfast crustose or stoloniferous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jania

19b. Pinnately branched; compressed segments (intergenicula) more than 300 μm wide; medulla of intergenicula mostly of 

3–25 tiers of cells; crustose holdfast (stolons absent, rare or sometimes along with crustose base) . . . . . . . . . . . . . . . 20

20a. Axes and branches mostly greater than 500 μm wide; intergenicula of 10–25 tiers of medullary cells; holdfast crustose 

(stolons absent or rare); reproductive conceptacles without or occasionally with short branchlets; fusion cells thin and 

broad; spermatangia conceptacles with low ceiling and short beaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Corallina

20b. Axes mostly less than 500 μm in diameter; intergenicula usually with 2 or more subcylindrical branchlets; intergenicula 

of 3–6 tiers of medullary cells; holdfast crustose (some also with stolons); tetrasporangial and carposporangial conceptacles with branchlets; fusion cells thick and compact; spermatangial conceptacles with high ceiling and without beaks or 

branchlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Haliptilon

Corallinaceae subfam. Corallinoideae

Corallinaceae subfam. Corallinoideae (Areschoug) Foslie, 1908:19; Womersley and Johansen, 1996:288; Bailey and Chapman, 1998:692; Bailey, 

1999:208; Harvey et al., 2003a:994.

Algae usually erect, sometimes procumbent, of terete to 

compressed branches of genicula (joints) that alternate with 

longer intergenicula (segments); arising above a crustose holdfast, lowermost basal segments with basal stolons in some species. Intergenicula of medulla of laterally adjoined filaments in 

1–25(–40) tiers of cells; vegetative filaments linked by lateral cell 

fusions; secondary pit connection absent; cortex of calcified cells. 

Genicula uncalcified; of a single tier of cells.

Life history of isomorphic tetrasporophytes and gametophytes. Zonate tetrasporangia and bisporangia produced in urnshaped or embedded conceptacles. Gametophytes monoecious or 

dioecious, with axial or lateral conceptacles. Carpogonial filaments 

2-celled, borne on conceptacle floor; carposporangia terminal on 

short gonimoblast filaments from basal fusion cell. Spermatangia 

on short filaments from floor or sides of conceptacle chamber.

Remarks. The subfamily is represented by two genera belonging in separate tribes in the northern Gulf of California. 

KEY TO THE TRIBES OF CORALLINACEAE SUBFAM. CORALLINOIDEAE 

IN THE NORTHERN GULF OF CALIFORNIA

1a. Fronds attached by an expansive crustose holdfast; sporangial conceptacles contain more than 30 tetrasporangia or 

bisporangia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Corallineae

1b. Frond(s) attached by minute to small crustose holdfast; sporangial conceptacles contain up to 15 tetrasporangia or 

bisporangia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Janieae

Corallinoideae tribus Corallineae

Corallineae Areschoug, 1852:509.

The articulated corallines of the tribe Corallineae are 

composed of calcified fronds of algae that are of pinnately, dichotomously, or irregularly branched and usually attached by 

spreading crustose holdfasts (lacking stolon-like attachments). 

Intergenicula are subcylindrical or compressed, with wings or 

lobes sometimes present, and more than eight cells in the medullary tiers of an intergeniculum. 

Sporangial conceptacles contain more than 30 tetrasporangia 

or bispores. Carposporangial conceptacles have concave-convex 

fusion cells, up to 10 μm thick. Spermatangial conceptacles are 

pointed or beaked, with spermatangia lining the floor and lower 

inner walls of the chamber. 

Remarks. One genus, Bossiella P. C. Silva (1957a), was 

mistakenly reported in the southern Gulf from Bahía de La Paz. 

The record of B. orbigniana (Descaine) P. C. Silva (RiosmenaRodríguez et al., 1992) was based on an incorrect locality label 

(see Riosmena-Rodríguez and Woelkerling, 2000). Also, the 
8 0 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

report of Bossiella californica (Descaine) P. C. Silva (1957a) in 

the upper Gulf of California (Martínez-Lozano et al., 1991) 

needs to be verified.

The tribe Corallineae is currently represented by one genus 

in the northern Gulf of California.

Corallina Linnaeus

Corallina Linnaeus, 1758:646, 805.

Algae are of articulated, calcified, pinnately branched 

fronds, attached by a basal crustose that can be extensive. Intergenicula calcified and composed of arching tiers of medulla cells 

of same length, an outer cortex of pigmented cells, and single 

layer of epithallial cells. Cells of the adjoining filaments often 

fuse, with nuclear migration occurring between cells; secondary 

pit connections are absent. Genicula are uncalcified, composed 

of single tiers of long, thick-walled cells (sometimes partly calcified by overlapping ends of the intergenicula). Trichocysts, although present, are not always evident; in surface view with a 

central pore and a rounded base. 

If fronds are grazed or removed by storms or other physical 

disturbances, the species can persist vegetatively by their crustose 

holdfasts and later grow new erect fronds. Reproductive conceptacles are axial, one per intergeniculum, usually bulging from the 

surface with a central pore. Conceptacles in some may occasionally bear branches. Pseudolateral conceptacles, when present, 

bulge conspicuously from intergenicular surfaces. Tetrasporangial conceptacles contain more than 30 tetrasporangia prior to 

spore discharge; bisporangia, although reported, are apparently 

rare. Sporangial initials divide into stalk cells with young sporangia that develop into zonate tetrasporangia. Gametangial thalli 

are dioecious. Carposporangial conceptacles are rounded and 

sometimes may have branches. Internally, they have an extensive 

layer of supporting cells that bear carpogonial filaments, each 

with a trichogyne that extends through the pore. After fertilization, a broad, thin fusion cell develops within the conceptacle 

and bears carposporangial filaments along its edges and sometime on the upper surface. 

Spermatangial conceptacles with a pore on the characteristic 

projecting point (“beaked”) on the roof and internally with an 

upper conceptacle canal usually more than 100 μm in length. 

Spermatangial parent cells produced from densely packed layer 

of basal cells on floor and walls of conceptacle chamber. Plastids 

degenerating in spermatangial parent cells as they bud off spermatangia, each spermatia has a nucleus-containing “head” and 

an elongate “tail.”

Remarks. Corallina is widespread in temperate and 

boreal regions, less common in subtropical areas, and absent in 

the tropics. Species are found from the intertidal to shallow subtidal, usually growing on rocks or other hard substrata, but may 

occasionally be epiphytic or epizoic. Their fronds sometimes also 

provide habitat for small invertebrates, such as amphipods and 

worms, which can bind their fronds together. In general, among 

the articulated corallines in the northern Gulf, Corallina can be 

distinguished by its pinnate branching.

Currently five taxa, four species, including a single variety 

of one species and another with two varieties, are recorded in the 

northern Gulf of California.

KEY TO THE SPECIES OF CORALLINA IN THE NORTHERN GULF OF CALIFORNIA

1a. Intergenicula cylindrical or only slightly compressed; main axes intergenicula with 3 or more lateral branches (appearing 

polystichous or verticillate); conceptacles terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. polysticha

1b. Intergenicula subcylindrical basally, compressed to flattened upward, conceptacles terminal or terminal and lateral on 

flattened surfaces of intergenicula . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Conceptacles predominately only terminal on flattened intergenicula; branching dichotous and pinnate, or mostly 

verticillate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2b. Conceptacles both terminal and lateral on flattened to digitate intergenicula; branching opposite, pinnate or plumose 

(lower portions sometimes tending toward whorled) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3a. Branching distichous-pinnate; intergenicula greater than 1 mm wide and 1.5–1.7 mm long; lateral branches becoming 

shorter upward, not appressed to main axes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. officinalis var. chilensis

3b. Branching mostly verticillate; intergenicula mostly up to 0.75 mm (but less than 1 mm) wide and 1 mm long; lateral 

branches short, of more or less same length throughout, laterally appressed to main axes . . . . . . . . C. vancouveriensis

4a. Ultimate intergenicula simple, lanceolate or spatulate (sometimes slightly lobed) . . . . . C. pinnatifolia var. pinnatifolia

4b. Ultimate intergenicula pinnate, palmate, or flabellate, predominately digitately lobed . . . . C. pinnatifolia var. digitata

Corallina officinalis var. chilensis (Decaisne in Harvey) Kützing

FIGURE 36A

Corallina chilensis Decaisne in Harvey, 1849a:103; Smith, 1944:230, pl. 51: 

fig. 4; Taylor, 1945:45, pl. 62.

Corallina officinalis var. chilensis (Decaisne in Harvey) Kützing, 1858:32, 

pl. 66: fig.1; Yendo, 1902c:718, pl. 54: fig. 1, pl. 56: fig. 15; Dawson, 1953a:132, pl. 28: fig. 1; Dawson et al., 1960a:56, pl. 23: fig. 

4; Dawson, 1961b:418; Dawson et al., 1964:45, pl. 62: figs. A, 

B; Dawson and Neushul, 1966:177; Abbott and North, 1972:75; 

Johansen, 1976a:405, fig. 354; Littler and Littler, 1981:148; 

Pacheco-Ruíz and Aguilar-Rosas, 1984:72, 76; Mendoza-González 

and Mateo-Cid, 1985:28; 1986:423; Sánchez-Rodríguez et al., 

1989:43; Scagel et al., 1989:168; R. Aguilar-Rosas et al., 1990:124; 

Martínez-Lozano et al., 1991:15; Stewart, 1991:84; Dreckmann, 
NUMBER 96 • 8 1

1991:33; Ramirez and Santelices, 1991:202; R. Aguilar-Rosas and 

Aguilar-Rosas, 1994:520; González-González et al., 1996:193; 

Riosmena-Rodríguez and Woelkerling, 2000:322; CastañedaFernández de Lara et al., 2010:199, tbl. 1.

Corallina officinalis f. robusta Setchell et N. L. Gardner, 1903:365.

Calcified articulated fronds, up to 13 cm tall; of few to several erect main axes of flat intergenicula, up to 1.5 mm long 

and 1–2 mm wide (at distal end); intergenicula loosely branched 

opposite pinnately on their upper ends, in more or less 1 plane, 

up to 3 orders; lateral branches subterete to flattened; ultimate 

branchlets lanceolate, sometimes elongated; fronds arising from 

a spreading crustose base.

Reproductive conceptacles mostly 500–600 μm in diameter.

Habitat. On rocks and in tide pools; low intertidal 

to shallow subtidal.

Distribution. Gulf of California: Bahía Kino. 

Eastern Pacific: Alaska Peninsula, Alaska to Isla Magdalena 

(NW side of Bahía Magdalena), Baja California Sur; California 

Channel Islands to Islas Todos Santos (off Ensenada), Baja California; Ecuador; Peru; Chile. Western Pacific: Japan.

Type Locality. Valparaíso, Valparaíso Province, 

central Chile.

Remarks. Corallina officinalis var. chilensis is well 

known on the Pacific coast of North America (Johansen, 1976a; 

Scagel et al., 1989; Lindeberg and Lindstrom, 2010). The Gulf 

of California records of C. officinalis var. chilensis are based on 

the reports of Mendoza-González and Mateo-Cid (1986) and 

Martínez-Lozano et al. (1991); since I have not seen their specimens, the description is based on Dawson (1953a).

Corallina pinnatifolia (Manza) E. Y. Dawson var. pinnatifolia

FIGURE 37A

Joculator pinnatifolius Manza, 1937:47; Manza, 1940:263, pl. 1: figs. 1, 2; 

Taylor, 1945:198, pl. 61.

Corallina pinnatifolia (Manza) E. Y. Dawson, 1953a:124, pl. 9: figs. 

7–13; 1961b:418; 1962c:278; 1966a:18; Abbott and North, 

1972:75; Johansen, 1976a:405, fig. 355; Huerta-Múzquiz, 

1978:336; Littler and Arnold, 1982:309; Stewart, 1982:54; 

Pacheco-Ruíz and Aguilar-Rosas, 1984:72, 76; L. Aguilar-Rosas et 

al., 1985:125; Huerta-Múzquiz and Mendoza-González, 1985:50; 

FIGURE 36. Species of Corallina. A. Corallina officinalis var. chilensis: Habit (EYD-53, AHFH, now UC). B. Corallina vancouveriensis: Habit

(EYD-147, AHFH, now UC).
8 2 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Mendoza-González and Mateo-Cid, 1985:48; Mendoza-González 

and Mateo-Cid, 1986:423; Stewart, 1991:84, fig. 5 (left); Dreckmann, 1991:33; Mateo-Cid et al., 1993:46; González-González et 

al., 1996:193; Riosmena-Rodríguez and Woelkerling, 2000:329; 

R. Aguilar-Rosas et al., 2005:32.

Calcified articulated fronds mostly in compact clumps, with 

individual axes up to 4 cm long. Axes usually densely, pinnately 

to plumosely branched; axial intergenicular segments, up to 

1.0(–1.5) mm long and up to 2 mm wide, with every intergenicular segment bearing mostly flattened and irregularly lobed, 

nonaxial indeterminate and determinate laterals. Laterals of subcylindrical to compressed segments, upward becoming flattened, 

usually as long as wide, up to 1.5 mm long; with a midrib and 

winged. Ultimate lateral branchlets usually irregularly lanceolate, sometimes spatulate or awl shaped.

Tetrasporangial conceptacles usually more abundant in 

lower portions of thalli; predominately terminal on modified cylindrical segments, with the tips markedly swollen (appearing to 

be pedicellate) or borne on flat segments or irregularly distributed and protruding on segment surfaces. Spermatangial conceptacles more or less terminal on lateral branches; appearing 

pedicellate with an elongated rostrum.

Habitat. On rocks and in tide pools; intertidal.

Distribution. Gulf of California: Puerto Peñasco to 

San Felipe. Eastern Pacific: Santa Cruz Island (California Channel Islands); Santa Barbara County, California, to Punta Márquez 

(north of Todos Santos), Baja California Sur; Galápagos Islands.

Type Locality. Rocky reef; Doheny State Beach, 

Dana Point, Orange County, southern California, USA.

Remarks. Riosmena-Rodríguez and SiqueirosBeltrones (1995) have questioned whether the Gulf of California 

specimens belong to Corallina pinnatifolia, suggesting all Gulf 

material may be C. vancouveriensis. The northern Gulf of California specimens referred to Corallina pinnatifolia or to C. vancouveriensis need to be compared to type locality material of 

each of these species using morphological and molecular DNA 

FIGURE 37. Species of Corallina. A. Corallina pinnatifolia var. pinnatifolia: Habit (EYD-10673, US Alg. Coll.-6998). B. Corallina polysticha:

Branch of type specimen, showing the characteristic whorled, spine-like branchlets (after Dawson 1953a, pl. 9: fig. 6). C–E. Corallina pinnatifolia var. digitata: Details of intergenicula branch shapes (C, D, JN-3687, US Alg. Coll.; E, JN-4593, US Alg. Coll.).
NUMBER 96 • 8 3

analyses. Until this can be done, the two species are recognized 

in the northern Gulf.

Corallina pinnatifolia var. digitata E. Y. Dawson

FIGURE 37C–E

Corallina pinnatifolia var. digitata E. Y. Dawson, 1953a:125, pl. 9: figs. 14–

20, pl. 30: fig. 1; 1959a:20; 1961b:418; 1966a:18; Huerta-Múzquiz, 

1978:337; Mendoza-González and Mateo-Cid, 1985:28; HuertaMúzquiz and Mendoza-González, 1985:50; Mendoza-González and 

Mateo-Cid, 1985:423; Stewart, 1991:84, fig. 5; Dreckmann, 1991:33; 

González-González et al., 1996:194; Riosmena-Rodríguez and Woelkerling, 2000:324.

Corallina pilulifera sensu Dawson, 1944a:275; Dreckmann, 1991:33 [non 

Corallina pilulifera Postels et Ruprecht, 1840:20].

Corallina frondescens sensu Johansen, 1976a:403, fig. 353 [in part; with reference to Gulf of California only]; Littler and Littler, 1981:150, 151, 

153; Mendoza-González and Mateo-Cid, 1986:423; Dreckmann, 

1991:33; Mateo-Cid et al., 1993:46; Pacheco-Ruíz and ZertucheGonzález, 2002:467; Pacheco-Ruíz et al., 2008:208 [non Corallina 

frondescens Postels et Ruprecht, 1840:20].

Bossiella frondescens sensu Hollenberg and Abbott, 1966:64 [in part; reference to Gulf of California only; non Bossiella frondescens (Postels et 

Ruprecht) E. Y. Dawson, 1964:540].

Calcified articulated fronds usually in compact clumps, with 

individual axes up to 4 cm long. Axes densely, pinnately to plumosely branched, every segment bearing lateral branches; axial 

intergenicular segments up to 1 mm long and up to 2 mm wide. 

Lateral segments flattened, characteristically flabellate to digitate, 

up to 2 mm long. Ultimate intergenicula larger, noticeably digitate.

Tetrasporangial conceptacles usually congested, in swollen 

terminal portions of modified cylindrical segments or in flattened 

segments; irregularly distributed on segment surfaces; primary 

conceptacles sometimes develop secondary conceptacles.

Habitat. On rock or other hard substrates; mid to 

low intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Isla Turner (Turners), off SE end of Isla Tiburón); Bahía Agua 

Verde; Bahía Bocochibampo to Punta Colorado (vicinity of 

Guaymas). Eastern Pacific: Punta Santa Rosaliita (“Punta Santa 

Rosalía”), Baja California to Isla Magdalena (NW side of Bahía 

Magdalena), Baja California Sur.

Type Locality. Punta Colorado, vicinity of Guaymas, Sonora, Gulf of California, Mexico.

Remarks. Dawson (1966a) noted most of the Gulf 

of California specimens were Corallina pinnatifolia var. digitata. Although the variety C. pinnatifolia var. digitata was later 

considered to be conspecific with C. frondescens (Johansen, 

1976a), their relationship is in need of reexamination. Northern Gulf C. pinnatifolia var. digitata should also be compared 

to the southern California C. pinnatifolia (Manza) E. Y. Dawson var. pinnatifolia (Dawson, 1953a). Riosmena-Rodríguez and 

Siqueiros-Beltrones (1995) have suggested all Gulf of California 

specimens identified as species of Corallina might be ecological variants of C. vancouveriensis. For now the northern Gulf 

C. pinnatifolia var. digitata is kept separate from the Alaskan 

C. frondescens (type locality: Unalaska Island in the Fox Islands 

group, eastern Aleutian Islands) and from the southern California C. pinnatifolia var. pinnatifolia and the British Columbian 

C. vancouveriensis. Studies of DNA genetic and morphological 

variability might spur the monographic studies needed to test the 

species limits and phylogenetic relationship of these taxa.

Corallina polysticha E. Y. Dawson

FIGURE 37B

Corallina polysticha E. Y. Dawson, 1953a:131, pl. 9: fig.6; pl. 29: fig. 

2; 1961b:418; Abbott and North, 1972:75; Johansen, 1976a:405, 

fig. 356; Aguilar-Rosas, 1981:93; Pacheco-Ruíz and Aguilar-Rosas, 

1984:72, 76; Stewart and Stewart, 1984:143; Mendoza-González 

and Mateo-Cid, 1985:28; Mendoza-González and Mateo-Cid, 

1986:423; Stewart, 1991:84; Anderson, 1991:22; Dreckmann, 

1991:33; Mendoza-González and Mateo-Cid, 1994:51; GonzálezGonzález et al., 1996:194; Riosmena-Rodríguez and Woelkerling, 

2000:329; Riosmena-Rodríguez et al., 2005a:33.

Calcified articulated fronds, erect and stiff, usually clumped 

together above a crustose base, up to 4 cm tall; axes in lower portions often unbranched, up to 1.0 mm in diameter, gradually narrowing in diameter upward, remaining unbranched or with a few 

branches; axial intergenicula subcylindrical or only slightly compressed; mostly less than 1.0 mm long. Intergenicula of secondary 

branches with (2–)3–10 polystichous or verticillate branches.

Reproductive conceptacles ovoid, up to 500 μm in diameter; 

subsessile or terminal on short lateral branches (appearing verticillate). (Description is based on Dawson, 1953a).

Habitat. On rocks; intertidal.

Distribution. Gulf of California: Isla Pelícanos, 

Bahía Kino. Eastern Pacific: Santa Catalina Island (California 

Channel Islands) to Bahía de Ballenas, Baja California Sur; Isla 

Guadalupe.

Type Locality. About 4 km (2.5 miles) north of 

South Bluff, Isla Guadalupe, off Baja California, Pacific Mexico.

Remarks. Apparently rare in the Gulf of California, 

Corallina polysticha is known in the northern Gulf only from the 

report of Mendoza-González and Mateo-Cid (1986). It is distinguished from other species of Corallina by its short spine-like 

branchlets that are polystichous (two or more per intergenicula) 

or whorled on the upper ends of the intergenicula (cf.Johansen, 

1976a: fig. 356). The relationship of Gulf C. polysticha needs to 

be molecularly tested with type and type locality specimens of 

other Corallina species.

Corallina vancouveriensis Yendo

FIGURE 36B

Corallina vancouveriensis Yendo, 1902c:719, pl. 54: fig. 3, pl. 55: figs. 1, 2, 

pl. 56: figs. 16, 17; Dawson, 1953a:126, pl. 28: fig. 2; Dawson et al., 

1960a:56, pl. 21: figs. 2–4; Dawson, 1960a:43; 1961b:418; 1964:542; 

Hollenberg and Abbott, 1966:62; Johansen, 1976a:405, fig. 357; Littler 

and Littler, 1981:150; Littler and Arnold, 1982:309; Pacheco-Ruíz and 

Aguilar-Rosas, 1984:72, 76; Stewart and Stewart, 1984:143; L. Aguilar-
8 4 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Rosas et al., 1985:125; Mendoza-González and Mateo-Cid, 1985:28; 

Mendoza-González and Mateo-Cid, 1986:423; Scagel et al., 1989:169; 

Sánchez-Rodríguez et al., 1989:43; R. Aguilar-Rosas et al., 1990:124; 

Stewart, 1991:85, fig. 5 (right); Dreckmann, 1991:33; Mateo-Cid 

et al., 1993:46; Mateo-Cid and Mendoza-González, 1994b:39; R. 

Aguilar-Rosas and Aguilar-Rosas, 1994:521; Mendoza-González and 

Mateo-Cid, 1994:51; Riosmena-Rodríguez and Siqueiros-Beltrones, 

1995:187; González-González et al., 1996:194; Silva et al., 1996b:232; 

Riosmena-Rodríguez and Paul-Chávez, 1997:71; Rodríguez-Morales 

and Siqueiros-Beltrones, 1999:23; L. Aguilar-Rosas et al., 2000:129, 

131; Paul-Chávez and Riosmena-Rodríguez, 2000:147; RiosmenaRodríguez and Woelkerling, 2000:333; Cruz-Ayala et al., 2001:191; 

CONANP, 2002:139; Riosmena-Rodríguez et al., 2005a:33; MateoCid et al., 2006:56; Schubert et al., 2006:1212; Castañeda-Fernández 

de Lara et al., 2010:199, tbl. 1.

Corallina aculeata Yendo, 1902a:720, pl. 55: fig. 3, pl. 56: figs. 18, 19; Dawson, 1964:542.

Corallina vancouveriensis var. aculeata (Yendo) E. Y. Dawson, 1953a:128.

Corallina gracilis f. densa Collins in Collins et al., 1899: P.B.-A. exsiccati

no. 650; Collins, 1906a:112; Smith, 1944:230, pl. 50: figs. 3–5; Dreckmann, 1991:33.

Corallina vancouveriensis var. densa Yendo, 1902a:719, pl. 55: fig. 1, pl. 56: 

fig. 17.

Corallina gracilis var. lycopodioides W. R. Taylor, 1945:200, pl. 65; Dreckmann, 1991:33.

Corallina vancouveriensis var. lycopodioides (W. R. Taylor) E. Y. Dawson, 

1953a:129; Dreckmann, 1991:33.

Calcified articulated fronds violet to purplish, up to 10 cm 

tall; loosely tufted to mostly densely, pinnate-opposite to distichous branched, often tending toward verticillate branching. 

Lower axial intergenicula subcylindrical, 700–1000 μm wide 

and up to 1 mm long; upper intergenicula compressed, up to 1 

mm long and 1 mm wide, most bearing 2–5 branches, each up 

to 2 mm long; branches of 1 or more intergenicula, each usually 

with 1 or more branchlets. Ultimate branchlets (pinnae) simple, 

lobed, pinnate or digitate, usually up to 1 mm long, but narrower, only 100– 500 μm in diameter.

Reproductive conceptacles up to 500 μm in outside diameter, terminal on short, thin pedicellate branchlets.

Habitat. On rocks and in tide pools; intertidal to 

shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Puertecitos; Isla Pelícanos (Bahía Kino); Puertecitos to Bahía 

de La Paz. Eastern Pacific: Bering Sea and Aleutian Islands, 

Alaska to Punta Lobos (near Todos Santos), Baja California Sur; 

Islas Todos Santos (off Ensenada), Baja California; Rocas Alijos, 

Baja California Sur; Galápagos Islands.

Type Locality. Port Renfrew, Vancouver Island, 

British Columbia, Canada.

Remarks. The several taxonomic varieties of Corallina vancouveriensis recognized by Dawson (1953a) were considered to be ecological variants of a single species by Johansen 

(1976a). The relationship of Gulf specimens referred to C. vancouveriensis to the type and to other similar species is in need 

of further investigation. Gulf of California C. vancouveriensis

should be critically compared to the British Columbian C. vancouveriensis, the Japanese Corallina confusa Yendo (1902a), 

and the Japanese “Corallina X” sensu Baba et al. (1988:15), 

which they said “appears to be identical with C. vancouveriensis” but which Yoshida (1998) later considered to be C. confusa 

Yendo (1902a).

Corallinoideae tribus Janieae

Corallinoideae tribus Janieae H. W. Johansen et P. C. Silva, 1978:414; Womersley and Johansen, 1996:296.

Calcified articulated algae of the tribe Janieae are erect 

fronds that are primarily dichotomously branched and attached 

by a minute to small crustose holdfast and stolon-like holdfasts. 

The intergenicula are cylindrical, subcylindrical, or compressed 

and may be smooth, winged, or lobed.

Sporangial conceptacles contain up to 12(–15) tetrasporangia or bisporangia. Fusion cells within the carposporangial conceptacles narrow and wide, to 35 μm in height, to 130 μm wide. 

Spermatangial conceptacles long and narrow, lanceolate; with 

spermatangia along the inner walls of chamber.

Remarks. J. H. Kim et al. (2007), using molecular analysis and morphological data, concluded that the three 

genera of the tribe, Jania, Haliptilon, and Cheilosporum (Decaisne) Zanardini (1844a, 1844b; basionym: Amphiroa sect. 

cheilosporum Descaine, 1842b), were congeneric, recognizing them as a single genus Jania. Later, Walker et al. (2009) 

suggested the taxonomic status and phylogenetic relationships 

of these three genera need further elucidation and should be 

based on type material. For now they are recognized as separate 

genera. 

Two genera of tribe Janieae are represented in the northern 

Gulf of California. 

KEY TO THE GENERA OF CORALLINACEAE SUBFAM. CORALLINOIDEAE TRIBUS JANIEAE 

IN THE NORTHERN GULF OF CALIFORNIA

1a. Cylindrical to subcylindrical axes primarily dichotomously branched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jania

1b. Compressed main axes primarily pinnately branched, with cylindrical to subcylindrical branches . . . . . . . . . Haliptilon

Haliptilon (Decaisne) Lindley

Jania sect. Haliptilon Decaisne, 1842b:123, as ‘Haliptylon.’ 

Haliptilon (Decaisne) Lindley, 1846:26.

Articulated coralline algae, with main axes that are mostly 

pinnately branched, with only a few dichotomous to subdichotomous branches, arising from a crustose or stoloniferous 

base. Adventitious branching is present in at least one species 
NUMBER 96 • 8 5

(H. roseum). Intergenicula are composed of 3–8 arching tiers of 

medullary cells that are often laterally fused, but without lateral 

pit connections. Cortex of intergenicula, composed of photosynthetic cortical cells, and an outermost single surface layer of 

epithallial cells. Genicula consist of a single tier of long, slender, 

straight, unbranched cells that are uncalcified. Trichocytes are 

present but not always evident; in surface view, trichocyte bases 

are elongate, and pores often excentric. 

Reproductive conceptacles, with a central pore, are developed in medullary meristems, axial and terminal on a fertile 

intergeniculum. Tetrasporangial and carposporangial conceptacles usually have extended branchlets. Tetrasporangial conceptacles are swollen and develop zonately divided tetrasporangia. 

Sexual thalli are dioecious. Carpogonial conceptacles contain 

the supporting cells and 2-celled carpogonial filaments (carpogonium with an elongated trichogyne) along its base. Carposporangia develop from short gonimoblast filaments near the 

edges of a relatively thick fusion cell. Spermatangial conceptacles are elongate ovoid to fusiform, without branchlets, with 

basal cells and spermatangial parent cells along the inside of its 

high walls.

Remarks. On the basis of their phylogenetic analyses of some members of the tribe Janieae, J. H. Kim et al. (2007) 

concluded that the genera Jania, Haliptilon, and Cheilosporum

(Descaine) Zanardini (1844a) should be merged into a single 

genus, Jania, as it is the oldest validly published. Because of the 

uncertain generic status of the taxon of Haliptilon in the Gulf 

of California, for now it is left in that genus until its taxonomic 

status can be investigated.

There is one taxon of Haliptilon reported in the Gulf of 

California.

Haliptilon roseum var. verticillatum (E. Y. Dawson) 

J. N. Norris, comb. nov.

Corallina gracilis var. verticillata E. Y. Dawson, 1953a:130, pl. 25: fig. 1; 

1961b:418; Stewart and Stewart, 1984:143; Huerta-Múzquiz and 

Mendoza-González, 1985:50; Mendoza-González and Mateo-Cid, 

1985:28; González-González et al., 1996:193.

Haliptilon gracile var. verticillatum (E. Y. Dawson) Garbary et H. W. Johansen, 1982:218.

Corallina subulata sensu Setchell and Gardner, 1930:179; Stewart and 

Stewart, 1984:143 [non Corallina subulata J. Ellis et Solander, 

1786:119; =Haliptilon subulatum (J. Ellis et Solander) H. W. Johansen, 1970:79].

Algae erect, calcified, articulate, up to 4 cm tall; in clumps 

of several main axes, subcylindrical below, compressed above, 

up to 600 μm in diameter, branching to 2–3(–5) orders; lateral 

branching prominent, more or less irregularly verticillate, lateral branchlets densely covering main axes, mostly 4–5 cm long, 

slender, attenuating upward to about 70 μm in diameter (rarely 

larger than 200 μm in diameter at base).

Reproductive conceptacles; ovoid, 300–450 μm with long, 

antenna-like extensions; terminal on long pedicel of ultimate 

branchlets. (Description after Dawson, 1953a.)

Habitat. On rocks; intertidal.

Distribution. Gulf of California: Bahía de La Paz.

Eastern Pacific: Santa Catalina Island (California Channel Islands); Isla Guadalupe (off Baja California).

Type Locality. On intertidal rocks; Isla Guadalupe, Baja California, Pacific Mexico.

Remarks. Reported in the southern Gulf, Haliptilon roseum var. verticillatum (Huerta-Múzquiz and MendozaGonzález, 1985, as Corallina gracilis var. verticillatum) has 

coarser main axes with prominent, irregular verticillate branches. 

It differs from H. roseum (Lamarck) Garbary et H. W. Johansen 

(1982) var. roseum as known in California (Johansen, 1976a, as

H. gracile (J. V. Lamouroux) H. W. Johansen, 1971, var. gracile), 

which has main axes that are pinnately branched in more or less 

distichous manner (i.e., alternately in two vertical rows on opposite sides of main axis).

Womersley and Johansen (1996; see also Johansen and 

Womersley, 1986), in recognizing Haliptilon roseum (Lamarck) 

Garbary et H. W. Johansen (1982), considered Corallina gracilis

J. V. Lamouroux (1816; basionym of H. gracilis (J. V. Lamouroux) H. W. Johansen, 1971) to be conspecific with the Australian Corallina rosea Lamarck (1815). Although the latter was 

referred to Jania rosea (Lamarck) Decaisne (1842b; see J. H. Kim 

et al., 2007:1317), Walker et al. (2009) stated that relationship 

of the genera Haliptilon and Jania was in need of further study.

Herein a new combination, H. rosea var. verticillata, is proposed for the Pacific Mexico variety. Comparisons of the littleknown Gulf of California material with type locality specimens 

of H. roseum var. verticillata need be studied to evaluate their 

generic placement and taxonomic status and phylogenetic relationship to the generitypes of Haliptilon, Corallina, and Jania.

Jania J. V. Lamouroux

Jania J. V. Lamouroux, 1812:186.

Articulated coralline thalli are erect, heavily calcified, dichotomously branched throughout, and may be attached to 

rocks or shells or epiphytic on other algae or sea grasses. They 

are primarily attached by a minute crustose base or initially by 

a crustose base and secondarily by stolons. Branching in most 

species is usually dichotomous. One species, J. huertae, is also 

trichotomously or polychotomously branched. Branchlets or 

pinnae are known in only a few taxa. Intergenicula (segments) 

are calcified and usually cylindrical or occasionally subcylindrical but in a few are compressed; they are usually considerably 

longer than broad and are composed of arching tiers of medullary cells, an outer cortex of pigmented cells, and an outermost 

single layer of epithallial cells. Medullary cells are in tiers that 

are all the same height. Cells are without pit connections. Trichocytes are present but are not always evident; trichocyte bases are 

elongate in surface view, with pores often excentric. Genicula 

(joints) are uncalcified and consist of a single tier of long, straight 

cells (sometimes partially covered by overlapping calcification of 

intergenicula).

Vegetative propagation can occur when a thallus or portions 

of the fronds become unattached and then entangled in other algae 
8 6 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

or may settle and continue to grow, reattaching by production 

of stolons. Reproductive structures begin development from the 

uppermost medullary cells. The conceptacles, with a central pore, 

are terminal on the intergenicula of branch apices. Tetrasporangial 

conceptacles contain fewer than 15 zonately divided sporangia that 

develop from an initial stalk and immature sporangium. Gametangial thalli are usually dioecious, although at least one species 

is monoecious. Carpogonial conceptacles have supporting cells 

and carpogonial filaments, each with a single carpogonium and 

an elongate trichogyne. After fertilization, gonimoblast filaments 

arise from the margins of narrow thick fusion cells and bear carpospores. Spermatangial conceptacles are long and narrow, more 

or less lanceolate (Johansen, 1972); inside chambers are 90–250 

μm in diameter, with their upper walls lined with basal cells and 

spermatangial parent cells and a canal up to 120 μm long.

Remarks. Two species are reported to occur in the 

southern Gulf (Dawson, 1953a, 1959a, 1961b; Huerta-Múzquiz 

and Mendoza-González, 1985; Riosmena-Rodríguez and 

Woelkerling, 2000): Jania subpinnata E. Y. Dawson (1953a), 

described from La Paz, Baja California Sur, and J. pacifica Areschoug (1852; type locality: Huatulco, Oaxaca) from Bahía de 

La Paz (Cruz-Ayala et al., 2001) and Bahía de Banderas, NayaritJalisco (Serviere-Zaragoza et al., 1993a, 1998), and in Pacific 

Mexico from Michoacán to Oaxaca (León-Tejera et al., 1993). 

Eight taxa, including seven species, one with a unique variety, are reported in the northern Gulf of California.

KEY TO THE SPECIES OF JANIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli of markedly compressed intergenicula throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. tenella var. zacae

1b. Thalli of cylindrical intergenicula throughout or to only slightly compressed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Thalli dichotomously, subdichotomously, and trichotomously branched and sometimes polychotomously branched 

(giving a whorled appearance) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. huertae

2b. Thalli dichotomously branched throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Thalli decussately dichotomously branched; branch angles wide, mostly greater than 45°; branch intergenicula (segments) 60–180 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3b. Thalli not decussately branched; branch angles narrower, mostly less than 45°, but up to about 30°; branch intergenicula 

(segments) mostly 120–200 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4a. Branch angles wide, 60°–90o; branch intergenicula (segments) mostly 60–100 μm in diameter; mostly 5–6 times longer 

than wide, 300–600 μm in length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. capillacea

4b. Branch angles also wide, up to or often greater than 45°; branch intergenicula wider in diameter, mostly 120–180 μm; 

about 2.5–5.0 times longer than wide, 300–900 μm in length . . . . . . . . . . . . . . . . . . . . . . . . . . J. decussato-dichotoma

5a. Branch angles mostly less than 30°; branch intergenicula 120–200 μm in diameter; 2–5 times longer than wide, 240–

700(–1000) in length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. adhaerens

5b. Branch angles usually narrow; intergenicula 60–200 μm in diameter, 2.5–11 times longer than wide . . . . . . . . . . . . . . 6

6a. Branching not densely dichotomous; branch intergenicula very long, 6–11 times longer than wide, 720–1650 μm in 

length; mostly wider in diameter, 120–150 (–210) μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J. longiarthra

6b. Branching more or less densely subdichotomous in upper portions; branch intergenicula shorter in length, 1–5 times 

longer than wide, about 100–600(–800) μm in length; usually narrower in diameter, 60–150 μm in diameter . . . . . . . 7

7a. Branch intergenicula narrow, 60–120 μm in diameter; mostly 2.5–5.0 times longer than wide, 150–600 μm in length; 

tetrasporangial conceptacles terminal (not conspicuously or predominately seriate) . . . . . . . . . . . . J. tenella var. tenella

7b. Branch intergenicula 120–150(–200) μm in diameter; mostly 1–2 times longer than wide, 120–150 in diameter in upper 

portions and 170–205 μm in lower portions; tetrasporangial conceptacles seriate . . . . . . . . . . . . . . . . . . . . J. mexicana

Jania adhaerens J. V. Lamouroux

FIGURES 38, 39A

Jania adhaerens J. V. Lamouroux, 1816:270; Yendo, 1902a:24, pl. 3: fig. 

4; pl. 7: fig. 5; Setchell and Gardner, 1930:179; Dawson, 1961b: 

419; Huerta-Múzquiz and Tirado-Lizárraga, 1970:128; Johansen, 

1971:247; Abbott and North, 1972:76; Johansen, 1976a:418, fig. 

370 [in part, excluding J. decussato-dichotoma]; Littler and Arnold, 1982:309; Huerta-Múzquiz and Mendoza-González, 1985:50; 

Stewart, 1991:86; Sánchez-Rodríguez et al., 1989:43; Mateo-Cid 

and Mendoza-González, 1991:20; Dreckmann, 1991:33; Mateo-Cid 

and Mendoza-González, 1992:20; Mendoza-González and MateoCid, 1992:18; León-Tejera and González-González, 1993:496; 

Serviere-Zaragoza et al., 1993a:484; Mateo-Cid et al., 1993:46; 

Mateo-Cid and Mendoza-González, 1994b:39; Mendoza-González 

et al., 1994:106; González-González et al., 1996:413; Anaya-Reyna 

and Riosmena-Rodríguez, 1996:864, tbl. 1; Riosmena-Rodríguez 

and Paul-Chávez, 1997:71; Yoshida, 1998:566; Serviere-Zaragoza 

et al., 1998:174; Riosmena-Rodríguez et al., 1998:28; RodríguezMorales and Siqueiros-Beltrones, 1999:23; Johansen, 1999:187, 

fig. 187; L. Aguilar-Rosas et al., 2000:131; Riosmena-Rodríguez 

and Woelkerling, 2000:320; Mateo-Cid et al., 2000:64; Cruz-Ayala 

et al., 2001:191; CONANP, 2002:139; Hernández-Herrera et al., 

2005:148; Serviere-Zaragoza et al., 2007:10; Pacheco-Ruíz et al., 

2008:208; Castañeda-Fernández de Lara et al., 2010:200; FernándezGarcía et al., 2011:62.

Corallina adhaerens (J. V. Lamouroux) Kützing, 1858:40, pl. 83: fig. 2a–f.
NUMBER 96 • 8 7

Articulated coralline algae, small and erect; forming dichotomously branched brittle turfs, usually less than 2 cm tall; 

above a crustose base, and secondarily attached by creeping, rhizomatous basal segments with lateral discoid holdfasts. Branch 

apices generally acute angles, mostly less than 30°. Intergenicula 

(segments) heavily calcified, cylindrical, sometimes slightly flattened at branch dichotomies; mostly 100–200 μm in diameter 

and (240–)300–700(–1000) μm in length.

Tetrasporangial conceptacles vase shaped, surmounted with 

swollen branches, 200–300 μm in outside diameter and 300–350 

μm in length. Carposporangial conceptacles similar to tetrasporangial conceptacles in outer appearance. Male conceptacles different; long and narrow and not surmounted by branches.

Habitat. Epiphytic or on hard surfaces, such as 

rocks, and in tide pools; intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Punta Los Frailes; Mazatlán, Sinaloa to Jalisco. Eastern Pacific: southern California to Todos Santos, Baja California Sur; 

Isla Guadalupe; Isla Socorro (Islas Revillagigedo); Colima; 

Oaxaca; Ecuador. Central Pacific: Hawaiian Islands. Western 

Pacific: China; Japan; Korea; Vietnam.

Type Locality. “Méditerranée?” (Lamouroux, 

1816:270); locale was stated with doubt as “Mediterranean 

Sea?” (see Silva et al., 1996a; Lipkin and Silva, 2002).

Remarks. Yendo (1902a) noted that the original description of Jania adhaerens J. V. Lamouroux (1816) could also 

apply to his J. decussato-dichotoma Yendo (1905) as well. Since 

then, the distinctiveness of these two has been questioned by 

some ( e.g., Johansen, 1971; Yoshida, 1998), and Price and Scott 

(1992) have considered J. decussato-dichotoma conspecific with 

J. adhaerens. Others have continued to recognize them as separate species, e.g., Dawson (1953a) and Silva et al. (1987, 1996a).

Many of the Gulf specimens of Jania adhaerens and 

J. decussato-dichotoma are very close, making distinctions between the two in the Gulf difficult and raising the question of 

whether the Gulf of California has one or both species. For example, those of the upper Gulf from Puerto Peñasco (Dawson, 1966a, 

as J. decussato-dichotoma) are similar enough morphologically 

FIGURE 38. Jania adhaerens: A. Habit, epiphytic on Sargassum (JN-3632, US Alg. Coll.). B. Upper branches showing uncalcified genicula 

(joints) between intergenicula (JN & HWJ-73-7-12, US Alg. Coll.).
8 8 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 39. Branching pattern and branch width variation in species of Jania: A. Jania adhaerens (JN-3529, US Alg. Coll.). B. Jania crassa 

(drawn from type specimen, CN). C. Jania longiarthra (EYD-18920, US Alg. Coll.-8022). D. Jania capillacea (drawn from type specimen, 

TCD). E. Jania longiarthra (drawn from type specimen, AHFH, now UC). F. Jania mexicana (drawn from type specimen, MICH). 
NUMBER 96 • 8 9

to agree with the broadly defined species concept of J. adhaerens sensu Johansen (1976a). However, until detailed studies of 

the Gulf material can be compared to the types and type locality 

specimens of the Mediterranean J. adhaerens and the Japanese J. 

decussato-dichotoma, the two are kept separate.

Jania capillacea Harvey

FIGURES 8A, 39D

Jania capillacea Harvey, 1853:84; Taylor, 1945:195; Dawson, 1953a:116, 

pl. 9: fig. 1; Tanaka, 1956:57, fig. 6; Dawson, 1957a:4; 1957c:20; 

1959a:22; 1961b:419; 1966a:17; Chávez-Barrear, 1972b:269; 

Huerta-Múzquiz and Garza-Barrientos, 1975:8, 11; Huerta-Múzquiz, 

1978:338; Littler and Littler, 1981:151, 153; Schnetter and BulaMeyer, 1982:130, pl. 20: fig. C, pl. 21: fig. A; Stewart and Stewart, 

1984:144; Salcedo-Martínez et al., 1988:83; Dreckmann, 1991:33; 

León-Tejera and González-González, 1993:496; Serviere-Zaragoza et 

al., 1993a:484; Stout and Dreckmann, 1993:12; González-González 

et al., 1996:320, 398; Yoshida, 1998:567; Serviere-Zaragoza et al., 

1998:174; Riosmena-Rodríguez and Woelkerling, 2000:322; MateoCid et al., 2006:56; Bernecker, 2009:CD-Rom p. 59; Fernández-García 

et al., 2011:62.

Jania rubenssensu Dawson, 1944a:277 [in part; non Jania rubens (Linnaeus) 

J. V. Lamouroux, 1816:272; basionym: Corallina rubens Linnaeus, 

1758:806].

Articulated coralline algae forming short tufts, mostly less 

than 1.0 cm tall; branching dichotomously or sometimes more 

or less decussate; branch angles very wide, 60°–90°; attached by 

a disc, secondary attachment discs often found on portion of 

branches in contact with substratum. Intergenicula (segments) 

cylindrical, 50–100 μm in diameter (ultimate branches usually 

more slender), (240–)300–600(–1000) μm in length.

Asexual reproduction by triangular propagules, 150–200 

μm in diameter, with long antenna-like branches from each upper 

corner (Dawson, 1953a: pl. 9: fig. 1). Reproductive conceptacles 

apparently rare. Tetrasporangial conceptacles, terminal, about 

300 μm wide, upper end rostrate or with 2–3 antenna-like 

branches.

Habitat. Usually growing among other turf algae, 

sometimes on rocks or epizoic on sponges; intertidal.

Distribution. Gulf of California: Puerto Peñasco; 

Isla Ángel de la Guarda to Cabo San Lucas; Nayarit to Jalisco. 

Eastern Pacific: Isla Guadalupe; Isla Cedros; Isla Socorro (Islas 

Revillagigedo); Isla Clipperton; Baja California to Guerrero; El 

Salvador; Costa Rica; Panama; Colombia; Ecuador; Galápagos 

Islands.

Type Locality. Bahia Honda Key (Bahia Honda 

State Park), Florida Keys, Monroe County, Florida, USA.

Remarks. Although Jania capillacea is generally recognized as a distinct species (e.g., Wynne, 2005), Cribb (1983) 

and Price and Scott (1992) have considered it to be conspecific 

with J. adhaerens. The relationship of Gulf of California J. capillacea to Gulf J. adhaerens and to the type material of each these 

species needs to be tested.

Jania decussato-dichotoma (Yendo) Yendo

Corallina decussato-dichotoma Yendo, 1902a:25, pl. 3: figs. 1–3; pl. 7: figs. 

3, 4; Yendo, 1902b:194.

Jania decussato-dichotoma (Yendo) Yendo, 1905:37; Dawson, 1953a:117, 

pl. 27: fig. 3; 1959a:22; 1961b:419; 1966a:17; Johansen, 1971:247; 

Abbott and North, 1972:72; Huerta-Múzquiz, 1978:337; HuertaMúzquiz and Mendoza-González, 1985:50; Mendoza-González and 

Mateo-Cid, 1986:423; Dreckmann, 1991:33; González-González et al., 

1996:229; Riosmena-Rodríguez and Paul-Chávez, 1997:71; RiosmenaRodríguez and Woelkerling, 2000:323.

Jania rubens sensu Dawson, 1944a:277 [in part; non Jania rubens (Linnaeus) 

J. V. Lamouroux, 1816:272; basionym: Corallina rubens Linnaeus, 

1758:806].

Articulated coralline algae forming dense tufts, 1–2 cm tall, 1.0 

cm or more wide; branching irregularly decussate-dichotomous; 

branch angles usually wide, mostly over 45°. Intergenicula cylindrical, mostly 120–180 μm in diameter, about 2.5–5.0 times longer than wide (250–900 μm long). Branch apices blunt.

Tetrasporangial conceptacles infrequent, terminal, 210–300 

μm in diameter, urn shaped, slightly rostrate, with or without 

antenna-like extensions.

Habitat. On rocks or other hard substratum; sometimes on sponges; intertidal.

Distribution. Gulf of California: Puerto Peñasco to 

Punta Los Frailes; Jalisco. Eastern Pacific: San Diego, California.

Type Locality. Three syntype localities in Japan 

were listed by Yendo (1902a): Miskai (Kanagawa Prefecture), 

Honshū Island; Province Boshū (Chiba Prefecture), Honshū

Island; and Province Hiuga (Hyūga) (Miyazaki Prefecture), 

Kyûshû Island.

Remarks. Jania decussato-dichotoma has been considered a synonym of J. adhaerens (Johansen, 1971), but others 

continue to recognize them as separate (e.g., Silva et al., 1996a; 

Riosmena-Rodríguez and Woelkerling, 2000; Guiry and Guiry, 

2008–2010). (See also Remarks under Jania adhaerens.)

Jania huertae Chávez-Barrear

FIGURE 40

Jania huertae Chávez-Barrear, 1972a:133, figs. 1–5; Dreckmann, 1991:33; 

González-González et al., 1996:320; Riosmena-Rodríguez and Woelkerling, 2000:326.

Articulated coralline algae, 1.5–2.0 cm tall; branching dichotomous to subdichotomous, trichotomous, or sometimes 

polychotomous (appearing verticillate); branch angles up to 45°. 

Intergenicula cylindrical, 50–60 μm in diameter, 5–7 times longer than wide, 250–360 (-420) μm in length. Some branches flagelliform, of 20–22 narrow intergenicula, basally 30–40 μm in 

diameter, decreasing upward to 10 μm or less in diameter.

Tetrasporangia unknown. Carposporangial conceptacles 

330 μm long, 170 μm wide; variable in position, sometimes terminal or at base of branches. Spermatangia unknown.

Habitat. Growing with other turf-forming algae; 

intertidal.
9 0 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Distribution. Gulf of California: Isla Pelícanos, 

Bahía Kino.

Type Locality. Southeast of Isla Pelícanos, near 

Bahía Kino, Sonora, Gulf of California, Mexico.

Remarks. Jania huertae was described from the 

northern Gulf of California, where thus far it is only known 

from the type specimen. Chávez-Barrear (1972a) noted that 

some western Atlantic material from Yucatán, Gulf of Mexico, 

was also in agreement with the type specimen, commenting that 

the species has a wider distribution. Although J. huertae was 

reported from Quintana Roo (M. Aguilar-Rosas et al., 1998), 

Ortega et al. (2001) could not confirm its presence in Caribbean 

Mexico.

Jania longiarthra E. Y. Dawson

FIGURE 39C,E

Jania longiarthra E. Y. Dawson, 1953a:119, pl. 9: fig. 4, pl. 27: fig. 4; 

1957c:20; 1959a:22; 1959d:4; 1961b:420; Abbott and North, 

1972:76; Pedroche and González-González, 1981:66; Anderson, 

1991:29; Dreckmann, 1991:33; Serviere-Zaragoza et al., 1993a:484; 

González-González et al., 1996:229; Riosmena-Rodríguez and PaulChávez, 1997:71; Paul-Chávez and Riosmena-Rodríguez, 2000:147; 

FIGURE 40. Jania huertae (type): A. Subdichotomous branch. B. Trichotomous branching. C. Typical branching 

pattern (after Chávez-Barrear, 1972a: figs. 2, 4, 5).
NUMBER 96 • 9 1

Riosmena-Rodríguez and Woelkerling, 2000:326; Hernández-Herrera 

et al., 2005:148; Mateo-Cid et al., 2006:56; Bernecker, 2009:CD-Rom 

p. 59; Fernández-García et al., 2011:62.

Articulated coralline algae, erect, up to 2.5 cm tall, forming 

coarse tufts; usually densely dichotomously branched, sometimes 

irregularly decussate; branching at very narrow angles (much less 

than 30°); arising from a crustose base. Intergenicula cylindrical 

or occasionally compressed where branches arise, unconstricted, 

with smooth surfaces; (150–)200–500 μm in diameter, about 

6–11 times longer than wide (720–5500 μm in length). Genicula 

120–150(–210) μm long, about 125–260 μm in diameter.

Reproductive conceptacles not known.

Habitat. Growing among other turf algae; mid to 

low intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas; Isla Carmén to Isla Espíritu Santo; Nayarit to 

Jalisco. Eastern Pacific: Punta Banda (Baja California); Clipperton Island (Île de la Passion); Costa Rica.

Type Locality. Bahía San Gabriél, Isla Espíritu 

Santo, Baja California Sur, Gulf of California, Mexico.

Remarks. Originally described from the southern 

Gulf, Jania longiarthra has since been reported in the upper Gulf 

(Mateo-Cid et al., 2006). It differs from other species of Jania reported in the Gulf by its characteristically very long intergenicula 

(segments) and narrow angles of branching (Dawson, 1953a). 

A single Pacific Baja California specimen, from Bahía Sebastián 

Vizcaíno, was tentatively referred to J. longiarthra by Dawson 

(1953a). It has also been reported in the Indian Ocean (Silva et 

al., 1996a). Specimens of Gulf J. longiarthra can resemble the 

California Jania crassa J. V. Lamouroux (sensu Johansen, 1976a; 

Stewart, 1991), and their relationship to each other and especially to the type of J. crassa (Figure 39B; type locality: Dusky 

Sound, New Zealand) requires further study.

Jania mexicana W. R. Taylor

FIGURE 39F

Jania mexicana W. R. Taylor, 1945:197, pl. 60 [type specimen]; Dawson, 

1953a:119; 1961a:420; Huerta-Múzquiz and Tirado-Lizárraga, 

1970:128; Huerta-Múzquiz, 1978:339; Huerta-Múzquiz and 

Mendoza-González, 1985:50; Mendoza-González and Mateo-Cid, 

1986:423; Salcedo-Martínez et al., 1988:83; González-González et al., 

1996:229; Riosmena-Rodríguez et al., 2005a:34; Serviere-Zaragoza et 

al., 2007:10.

Articulated coralline algae forming small, erect, dense tufts, 

about 1.5–2.3 cm tall; subcorymbose; axes terete, intergenicular 

segments cylindrical, 240–425 μm long, 170–205 μm in diameter in lower portions, narrowed in upper portions, 120–150 μm 

in diameter; branch apices rounded.

Tetrasporangial conceptacles ovoid, about 300 μm in diameter, with two uppermost horn-like projections, later developing into antenna-like branchlets of 1 to several segments; each 

can repeatedly produce additional conceptacles, forming 1–4 

successive dichotomous divisions, making the reproductive 

branch more divergent than the vegetative branches. Cystocarpic 

branches not known. Spermatangial thalli of narrow branch angles; spermatangial conceptacles ellipsoidal, elongate, 450–600 

μm in length, 240–280 μm in diameter, with terminal acute apices (not antenna-like); spermatia fusiform, about 5 μm long, 2 

μm in diameter. (Description after Dawson, 1953a).

Habitat. Growing on rocks or sometimes attached 

to barnacles; intertidal.

Distribution. Gulf of California: Segundo Cerro 

Prieto to Roco Rojo, Bahia Kíno; Isla Tiburón and Estero Punta 

Perla (on Isla Tiburón); Báhia de La Paz; Mazatlán, Sinaloa to 

Jalisco. Eastern Pacific: Bahía de Ballenas, Baja California Sur; 

Colima to Oaxaca; Islas Revillagigedo.

Type Locality. Bahía de Petatlán, vicinity of Zihuatanejo, Guerrero, Pacific Mexico.

Remarks. Apparently more common on the tropical 

mainland coast of Pacific Mexico, Jania mexicana has also been 

reported in the northern Gulf by Mendoza-González and MateoCid (1986). A densely tufted species, the successive compounding of the tetrasporangial conceptacles is apparently unique to J. 

mexicana (Dawson, 1953a). Since I have not seen their collections, 

the description is based on Taylor (1945) and Dawson (1953a).

Jania mexicana (Figure 39F: isotype, MICH), described 

from Bahía de Petatlán, Guerrero (15°34′N, 101°29′W), needs 

critical comparison with another Pacific Mexico species, J. pacifica Areschoug (1852), described from Huatulco, Oaxaca 

(15°78′N, 96°27′W). Silva et al. (1987) had earlier considered 

these two to be conspecific, and their relationship needs to be 

further tested.

Jania tenella (Kützing) Grunow var. tenella

Corallina tenella Kützing, 1858:41, pl. 85: fig. 2; Grunow, 1867:78 [as “Corallina (Jania) tenella”].

Jania tenella (Kützing) Grunow, 1874:42; Dawson, 1949b:25; 1953a:120, 

pl. 9, fig. 3 [isotype branch of Corallina tenella Kützing]; 1957a:6; 

1959a:22; 1959d:4; Dawson et al., 1960b:7; Dawson, 1961b:420; 

1966a:17; Abbott and North, 1972:76; Johansen, 1976a:418, fig. 

372; Devinny, 1978:360; Huerta-Múzquiz, 1978:339; L. AguilarRosas, 1981:93; Stewart and Stewart, 1984:144; Huerta-Múzquiz 

and Mendoza-González, 1985:50; Santelices and Abbott, 1987:8; 

Sánchez-Rodríguez et al., 1989:43; Dreckmann et al., 1990:30; 

Martínez-Lozano et al., 1991:24; Ramírez and Santelices, 1991:208; 

Mateo-Cid and Mendoza-González, 1991:20; Dreckmann, 1991:33; 

Mateo-Cid and Mendoza-González, 1992:20; Mendoza-González 

and Mateo-Cid, 1992:18; Servière-Zaragoza et al., 1993a:484; LeónTejera et al., 1993:200; Stout and Dreckmann, 1993:12; MendozaGonzález et al., 1994:106; Mendoza-González and Mateo-Cid, 

1994:51; León-Álvarez and González-González, 1995:363; GonzálezGonzález et al., 1996:229; Silva et al., 1996b:232; Anaya-Reyna 

and Riosmena-Rodríguez, 1996:864, tbl. 1; Serviere-Zaragoza et al., 

1998:174; L. Aguilar-Rosas et al., 2000:131; Riosmena-Rodríguez 

and Woelkerling, 2000:331; Cruz-Ayala et al., 2001:191; L. AguilarRosas et al., 2002:234; López et al., 2004:12; Hernández-Herrera et 

al., 2005:148; Silva and Chacana, 2005:110, fig. 5; Mateo-Cid et al., 

2006:56; Schubert et al., 2006:1212; Serviere-Zaragoza et al., 2007:10; 
9 2 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Bernecker, 2009:CD-Rom p. 59; Castañeda-Fernández de Lara et al., 

2010:200; Fernández-García et al., 2011:62.

Jania rubens sensu Setchell and Gardner, 1930:179 [non Jania rubens (Linnaeus) J. V. Lamouroux, 1816:272; basionym: Corallina rubens Linnaeus, 1758:806].

Articulated coralline algae forming dense tufts of congested branches, 1.0–2.0 cm tall, usually epiphytic, occasionally 

on rocks; branching dichotomous, at narrow angles; attached 

by a usually inconspicuous disc. Intergenicula cylindrical (or 

sometimes with lower intergenicula very slightly compressed), 

60–100(–120) μm in diameter, mostly 2.5–5.0 times longer than 

wide, 150–600(–720) μm in length.

Tetrasporangial and carposporangial conceptacles, urn 

shaped, up to 250 μm in diameter, with long extensions from 

prominent shoulders. Spermatangial conceptacles, elongate ellipsoidal, about 300 μm in length, 150 μm in diameter.

Habitat. Epiphytic on various algae, often covering 

much of the host; occasionally on rocks; mid to low intertidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Puerto Peñasco; Bahía de La Paz to 

Cabo Pulmo; Mazatlán, Sinaloa to Jalisco. Eastern Pacific: Santa 

Catalina Island (California Channel Islands); southern California to Bahía Magdalena, Baja California Sur; Rocas Alijos; Isla 

San Benedicto (Islas Revillagigedo); Colima to Guerrero; Costa 

Rica; Chile; Rapa Nui (Easter Island; Isla de Pascua). Western 

Pacific: Japan.

Type Locality. Syntype localities: “in sinu neapolitano et ad oras mexicanas” (Kützing, 1858:41). Lectotype locality: Golfo di Napoli, Italy, given by Dawson (1953a; Silva et al., 

1996a), and later Mexico, cited by South and Skelton (2003).

Remarks. Jania tenella is apparently restricted to the 

warmer subtropical waters of the Gulf of California.

Jania tenella var. zacae E. Y. Dawson

Jania tenella var. zacae E. Y. Dawson, 1953a:121, pl. 8: fig. 3, pl. 31: fig. 

1; 1957c:20; 1961b:420; 1962d:394; Anderson, 1991:30; LeónÁlvarez and González-González, 1995:363; González-González et al., 

1996:230; Serviere-Zaragoza et al., 1998:174; Riosmena-Rodríguez 

and Woelkerling, 2000:333; Bernecker, 2009:CD-Rom p. 59; 

Fernández-García et al., 2011:62.

Articulated coralline algae forming small epiphytic tufts of 

several erect, branched thalli, up to 1–2 cm tall; arising on a small 

discoid base, up to 1 mm in diameter. Dichotomously branched 

at very narrow angles; branch intergenicula compressed to flattened throughout, 130–160 μm wide, 2.0–2.5 times longer than 

wide, about 250–460 μm in length; upper branches narrower, 

70–100 μm wide, about 140–250 μm long.

Tetrasporangial conceptacles urn shaped, slightly compressed, about 300 μm wide; rostrate, with a simple or forked 

antenna-like branch from each upper shoulder. Carpogonial 

conceptacles unknown. Spermatangial conceptacles, more or less 

cylindrical, ellipsoid, about 150 μm in diameter, 300 μm long; 

terminal on branches, without antenna-like branches.

Habitat. On Padina and possibly other algae; intertidal.

Distribution. Gulf of California: Isla San Ildefonso (off Gulf coast of Baja California Sur, northeast of Punta 

Púlpito). Eastern Pacific: Punta Malarrimo (Bahía Sebastián Vizcaíno), Baja California Sur; Zihuatanejo, Guerrero; Costa Rica; 

Nicaragua.

Type Locality. Epiphytic on Padina; Bahía Piedra 

de Blanca, Pacific Costa Rica.

Remarks. Jania tenella var. zacae is included since it 

may occur in the northern Gulf and to call attention to the need 

to investigate its taxonomic status. Its segments are markedly 

compressed, thus differing from those of J. tenella var. tenella,

which are primarily terete.

Corallinaceae subfam. Amphiroideae

Corallinaceae subfam. Amphiroideae H. W. Johansen, 1969a:47; Garbary 

and Johansen, 1987:1–10; D. S. Choi and Lee, 1988:111, figs. 1–9; 

Womersley and Johansen, 1996:283.

Algae are erect, of terete to compressed, usually dichotomous or subdichotomous (or occasionally whorled) articulated 

branches composed of genicula (uncalcified joints) that alternate 

with longer intergenicula (calcified segments) and arise above a 

crustose holdfast. Intergenicula and genicula in Amphiroa are

similar in structure; the medulla is of laterally adjoined filaments 

in one or more tiers of cells; there are secondary pit connections 

between medullary cells, but cell fusions are absent, and the cortex of calcified intergenicula cells is a single tier of short cells 

separated by two to seven tiers of longer cells in Amphiroa.

Life histories are of isomorphic sporophytes and gametophytes. Bisporangia and zonately divided tetrasporangia are produced in urn-shaped or embedded conceptacles. Gametophytes 

are monoecious or dioecious, with axial or lateral conceptacles. 

Carpogonial filaments are two-celled, borne on the conceptacle 

floor. Carposporangia are terminal on short gonimoblast filaments developed from the basal fusion cell. Spermatangia are on 

short filaments arising the from the floor or sides of conceptacle 

chamber.

Remarks. Corallinaceae subfam. Amphiroideae is 

separated on the basis of characteristics of Amphiroa (Johansen, 1969b, 1981). The C. subfam. Amphiroideae may be distinguished from the C. subfam. Corallinoideae (which includes 

Corallina and Jania) by characteristics that are mostly evident 

by microscopic study (Johansen, 1969a, 1981), i.e., the presence 

of secondary pit connections, medullary tiers of varying heights, 

intergenicula that often have several tiers, a unique mode of development of tetrasporangial conceptacles (Johansen, 1968), 

the form of spermatangial conceptacles, and other characteristics. In addition to the macroscopic and microscopic characters 

of Amphiroa, D. S. Choi and Lee (1988) proposed that structures observed by scanning electron microscopy are also useful 

diagnostic characters at the subfamily level. They observed an 

“Amphiroa-type” thallus surface of epithallial concavities separated by smooth, flat calcified cell walls and observed trichocytes 

in the cell wall region to apparently have a simple pore and lack 
NUMBER 96 • 9 3

a differentiated base, in contrast to the distinctive trichocyte base 

found in Corallina-type and Jania-type (Garbary and Johansen, 

1982). Recognization of the subfamily Amphiroidese is problematic. Cabioch (1972, 1988) considered this subfamily to be 

the same as C. subfam. Lithophylloideae, placing Amphiroa in 

Lithophylloideae tribe Amphiroeae Cabioch (1972:266), and genetic analyses of Bailey (1999) also seemingly supports their of 

distinctiveness.

Until further investigations can be completed, the subfamily 

is tentatively recognized. It is well represented by members of 

one genus in the Gulf of California.

Amphiroa J. V. Lamouroux

Amphiroa J. V. Lamouroux, 1812:185.

Calcified articulated algae that are erect or recumbent, composed of numerous cylindrical, compressed or flattened intergenicula (segments frequently considerably longer than broad) 

that are separated from one another by much shortened uncalcified genicula (joints). Thalli are branched irregularly, dichotomously or subdichotomously and arise from a base attached to 

rocks or other hard surfaces by a crustose holdfast or by an endophytic peglike holdfast. Medullary cells of the intergenicula are in 

tiers of varying heights. Trichocytes in surface view are rounded. 

Cortex of the medulla is made up of short, smaller cells, sharply 

delimited from the longer medulla cells. Cells are attached laterally to each other by secondary pit connections. The genicula consist of 1 to several medullary tiers, corticated to varying extents.

Conceptacles are usually borne on surfaces and margins of 

the intergenicula but are reported to be basal in at least one. 

Tetrasporangia and bisporangia are either developed only in the 

periphery or center of the sporangial conceptacle chamber, or, in 

some, from both the periphery and center. Sporangial pore canal 

of some may have large block cells, but these are not present in 

others. Carposporangial filaments, producing carposporangia, 

are developed either from the margins or the entire surface of the 

fusion cell in the basal region of the chamber floor. Spermatangial conceptacles are usually low and broad, with spermatangia 

produced on the chamber floor.

Remarks. Emphasizing the importance of the development of reproductive conceptacles in Amphiroa, RosasAlquicira et al. (2013) found different patterns of development 

of the sporangial and gametangial conceptacles to be diagnostic 

for species within the genus. They also described the reproductive development in more detail for several of the species, including four from the Gulf of California.

Superficially, some small species of Gulf Amphiroa, e.g., 

A. valonioides, may sometimes resemble some members of Jania,

but upon examination with a hand magnifying lens their distinctions become clear. Although both are dichotomously branched, 

the genicula (joints) and positions of the conceptacles differ. Reproductive conceptacles are on the intergenicula (segments) surfaces and margins in Amphiroa and at the apices in Jania.

Five taxa have been reported in the southern Gulf from 

Sinaloa to Jalisco (Mateo-Cid and Mendoza-González, 1992; 

Mendoza-González and Mateo-Cid, 1992, 1994; ServiereZaragoza et al., 1993a; Mendoza-González et al., 1994; 

Riosmena-Rodríguez and Woelkerling, 2000): Amphiroa compressa Me. Lemoine (1930), A. compressa var. tenuis W. R. Taylor (1945), A. foliacea J. V. Lamouroux (1824), A. polymorpha

Me. Lemoine (1930), and A. currae Ganesan (1971; note that 

this last record is questioned by Serviere-Zaragoza et al., 1993a).

Currently nine species of Amphiroa are recognized in the 

northern Gulf of California.

KEY TO THE SPECIES OF AMPHIROA IN THE NORTHERN GULF OF CALIFORNIA

1a. Calcified intergenicula (segments) distinctly compressed (never or rarely cylindrical) . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Calcified intergenicula (segments) cylindrical to subcylindrical throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2a. Fronds recumbent, spreading, and irregularly branched; intergenicula irregularly shaped, variable in size up to 7 mm long 

and 3–4 mm wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. misakiensis

2b. Fronds erect, clumps, regularly branched; intergenicula less than 1 mm wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Intergenicula cylindrical to subcylindrical or slightly compressed, mostly less than 1 mm in diameter (700–1200 μm); 

genicula (noncalcified joints) of 3–5 tiers of medullary cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 

3b. Intergenicula more than 1 mm wide; genicula (noncalcified joints) of 6 or more tiers of medullary cells . . . . . . . . . . . . 5

4a. Intergenicula cylindrical to subcylindrical, 0.8–1.2 mm in diameter, of more or less similar diameter throughout, but 

irregular in lengths, segments (0–)1.5–4.0 times as long as wide, not often forked; genicula dark, conspicuous . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. mexicana

4b. Intergenicula cylindrical to slightly compressed, 0.5–1.0 mm in diameter, intergenicular segments more than 4 (sometimes 

up to 10) times long as wide; more frequently forked; genicula apparent (but not as dark) . . . . . A. beauvoisii (in part)

5a. Intergenicula up to 3 mm long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. brevianceps

5b. Intergenicula more than 5 mm long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. magdalenensis

6a. Intergenicula more than 1 mm in diameter; genicula consisting of 5 or more tiers of medullary cells . . . . A. vanbosseae

6b. Intergenicula less than 1 mm in diameter; genicula consisting of 4 or fewer tiers of medullary cells . . . . . . . . . . . . . . . 7

7a. Intergenicula less than 0.5 mm in diameter; genicula of 1 tier of medullary cells. . . . . . . . . . . . . . . . . . . A. valonioides

7b. Intergenicula 0.5–1 mm in diameter; genicula of 2 or more tiers of medullary cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
9 4 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

8a. Fronds mostly 2–12 cm tall, branched more or less in 1 plane; genicula of 3–5 tiers of medullary cells . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. beauvoisii (in part)

8b. Fronds less than 2 cm tall; genicula of 2 tiers of medullary cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

9a. Branching alternately pinnate to irregular; rigid branches irregular placed, mostly not formed at the genicula, and usually 

at wide angles; genicula cells imbricated; intergenicula more or less straight, 500–1000 μm, of similar diameter throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. rigida

9b. Branched multifariously or pinnately to irregularly in lower portions, and unbranched to sparsely dichotomous in upper 

portions; genicula cells blunt (not imbricated); intergenicula 250–450 μm in diameter, usually crooked and not uniform 

in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. taylorii

Amphiroa beauvoisii J. V. Lamouroux

FIGURE 41

Amphiroa beauvoisii J. V. Lamouroux, 1816:299; Hamel and Lemoine, 

1953:42, fig. 7 [text], pl. 5: figs. 1, 7; Dawson, 1957c:18; 1961b:420; 

Norris and Johansen, 1981:6, figs. 1a, 2, 3, 4a–c, 5, 7b, 14b, 15b; 

Johansen, 1981:70, fig. 12A; Stewart and Stewart, 1984:144; Norris, 1985d:208; Lewis and Norris, 1987:18; Garbary and Johansen, 

1987:3, figs. 7, 14, 15; Stewart, 1991:80; Ramírez and Santelices, 

1991:195; Dreckmann, 1991:33; Mateo-Cid et al., 1993:46; LeónTejera et al., 1993:200; Serviere-Zaragoza et al., 1993a:482; Stout and 

Dreckmann, 1993:12; Mateo-Cid and Mendoza-González, 1994b:39; 

Mendoza-González and Mateo-Cid, 1994:51; Mendoza-González 

et al., 1994:106; León-Álvarez and González-González, 1995;363; 

González-González et al., 1996:301; Anaya-Reyna and RiosmenaRodríguez, 1996:864, tbl. 1; Riosmena-Rodríguez and SiqueirosBeltrones, 1996:137, figs. 2–5; Riosmena-Rodríguez and Paul-Chávez, 

1997:71; Serviere-Zaragoza et al., 1998:171; Abbott, 1999:177, figs. 

44A,B, 45A; Rodríguez-Morales and Siqueiros-Beltrones, 1999:23; 

L. Aguilar-Rosas et al., 2000:130; Mateo-Cid et al., 2000:64; PaulChávez and Riosmena-Rodríguez, 2000:147; Riosmena-Rodríguez 

and Woelkerling, 2000:321; Cruz-Ayala et al., 2001:190; CONANP, 

2002:139; L. Aguilar-Rosas et al., 2002:234; Pacheco-Ruíz and 

Zertuche-González, 2002:467; Abbott et al., 2002:302; López et al., 

2004:10; R. Aguilar-Rosas et al., 2005:32; Riosmena-Rodríguez et 

al., 2005a:33; Mateo-Cid et al., 2006:51, 55; Serviere-Zaragoza et al., 

2007:9; Y.-P. Lee, 2008:181, figs. A–D; Mateo-Cid et al., 2008:8, figs. 

1–17, 22–44; Pacheco-Ruíz et al., 2008:208; Rosas-Alquicira et al., 

2008:129; Bernecker, 2009:CD-Rom p. 59; Castañeda-Fernández de 

Lara et al., 2010:199; Rosas-Alquicira et al., 2013:698, figs. 3–6, 8, 10, 

15–19, 25–26, 28–31, 33, 39, 52, tbls. 1, 2.

Amphiroa zonata Yendo, 1902a:10, pl. 1: figs. 11–14, pl. 4: fig. 9; Dawson, 1944a:276; 1953a:146; 1959a:22; Dawson et al., 1960a:44, pl. 

23: fig. 6; Dawson, 1961b:421; 1966a:18; Abbott and North, 1972:75; 

Johansen, 1976a:400, fig. 349; Devinny, 1978:360; Murata and Masaki, 1978:403, figs. 3–7, 18, 26, 27; Littler and Littler, 1981:151; 

Littler and Arnold, 1982:309; Stewart and Stewart, 1984:144; Tseng, 

1983:86, pl. 46: fig. 4; Mendoza-González and Mateo-Cid, 1985:26; 

Mendoza-González and Mateo-Cid, 1986:422; Sánchez-Rodríguez et 

al., 1989:42; Martínez-Lozano et al., 1991:24; González-González et 

al., 1996:173; Yoshida, 1998:538, fig. 3-14C–F; Riosmena-Rodríguez 

and Woelkerling, 2000:333; Schubert et al., 2006:1212; Bernecker and 

Wehrtmann, 2009:225.

Amphiroa peninsularis W. R. Taylor, 1945:188, pl. 48: fig. 1; Norris and Johansen, 1981:6; Salcedo-Martínez et al., 1988:83; Anderson, 1991:15; 

Riosmena-Rodríguez and Woelkerling, 2000:328.

Amphiroa drouetii E. Y. Dawson, 1953a:140, pl. 27, figs. 5, 6; 1959a:21; 

1961b:420; 1966a:18; Huerta-Múzquiz and Garza-Barrientos, 1975:8; 

Huerta-Múzquiz, 1978:339; Martínez-Lozano et al., 1991:24.

Amphiroa franciscana var. robusta E. Y. Dawson, 1953a:150; 1961b:421; 

1966b:59; Anderson, 1991:15; González-González et al., 1996:171, 

383; Riosmena-Rodríguez and Woelkerling, 2000:330. 

Amphiroa linearis sensu Hariot, 1895:169; León-Tejera and GonzálezGonzález, 1993:496; González-González et al., 1996:171, 382 [non 

Amphiroa linearis Kützing, 1858:22, pl. 46: fig. 2a–c]. 

Amphiroa pusilla sensu Dawson, 1944a:276 [in part; non Amphiroa pusilla

Yendo, 1902a:13]. 

Amphiroa crosslandii sensu Dawson, 1953a:149; 1954d:136; 1957a:7; 

1961b:420; Mendoza-González and Mateo-Cid, 1986:422; SalcedoMartínez et al., 1988:83; Dreckmann, 1991:33; González-González 

et al., 1996:170 [non Amphiroa crosslandii Me. Lemoine, 1929a:50; 

Tittley et al., 1984:5].

Fronds 1.5–4.0(–6) cm high, usually more or less erect and 

open, sometimes in compact, pulvinate clumps; attached by a crustose disc to hard substratum. Branching dichotomous to irregular, 

more or less in 1 plane; branch intergenicula sometimes Y-shaped 

dichotomies, sometimes separated by 1 or more unbranched intergenicula. Intergenicula near base cylindrical to subcylindrical, up 

to 1.2(–1.7) mm in diameter and 2–3(–4) mm long. Mid to upper 

intergenicula cylindrical, subcylindrical, or compressed (especially 

near branch apices); mostly 0.5–l.0 mm broad and 3–5(–10) mm 

long; becoming more terete with age because of cortical thickening. 

Genicula between intergenicula barely visible externally because of 

covering calcification; becoming visible by cracking and sloughing of calcified cortical cells overlying their uncalcified 3–5 tiers of 

medullary cells and irregularly disposed patches of cortical cells.

Reproductive conceptacles scattered over intergenicular 

surfaces, protruding slightly. Tetrasporangial and bisporangial 

conceptacles 150–250(–300) μm inside diameter, 95–150 μm 

tall; tetrasporangia (40–)60–65 μm tall, 25–35 μm in diameter; 

bisporangia 40–80 μm tall, 22–40(–45) μm in diameter. Sporangial conceptacle canal with large block cells; sporangia only in 

periphery of cavity floor (Rosas-Alquicira et al., 2013: fig. 8). 

Carpogonial filaments develop from entire surface of fusion cell. 

Basal cells of spermatangial conceptacle form by basal division 

of cavity cells; each basal cell produces 2 spermatangial parent 

cells that develop simple spermatangial filaments; spermatangia release spermatia into conceptacle chamber (after RosasAlquicira et al., 2013).

Habitat. On rocks and tidal platforms and in tide 

pools; mid intertidal to shallow subtidal.
NUMBER 96 • 9 5

Distribution. Gulf of California: Piedras de la Salina (Gulfo de Santa Clara) to Cabo San Lucas; Mazatlán, Sinaloa 

to Jalisco. Islas Marías (Islas Tres Marías). Eastern Pacific: Santa 

Catalina Island (California Channel Islands) to Playa Los Cerritos, Baja California Sur; Isla Socorro (Islas Revillagigedo); Rocas 

Alijos; Jalisco to Oaxaca; Costa Rica to Ecuador; Galápagos Islands; Chile. Central Pacific: Hawaiian Islands. Western Pacific: 

China; Taiwan; Korea; Japan; Vietnam.

Type Locality. Coast of Portugal (Harvey et al., 

2009).

Remarks. Primarily on the basis of similar morphologies, Amphiroa beauvoisii, A. drouetii, and A. zonata were considered to be conspecifc by Norris and Johansen (1981); since 

then, most have continued to recognize A. beauvoisii in the Gulf 

of California (Riosmena-Rodríguez and Siqueiros-Beltrones, 

1996; Riosmena-Rodríguez and Woelkerling, 2000; Mateo-Cid 

et al., 2006, 2008; Rosas-Alquicira et al., 2013). Others have recognized the western Pacific A. zonata (syntype localities: Misaki, 

Shimoda, and Sunosaki, Japan), the eastern Atlantic A. beauvoisii (type locality: Portugal) (e.g., Tseng, 1983; Silva et al., 1987; 

Yoshida, 1998), and the northern Gulf of California A. drouetii

(type locality: Isla Turner, off Isla Tiburón) as separate species 

(Mendoza-González and Mateo-Cid, 1986; Salcedo-Martínez 

et al., 1988; Sánchez-Rodríguez et al., 1989; Mateo-Cid and 

Mendoza-González, 1991; 1992; Mendoza-González and 

Mateo-Cid, 1992; González-González et al., 1996). Differences 

have been observed in sporangial conceptacles of species presumed to be the same or related. Sporangia were only on the 

periphery of the chamber floor in A. beauvoisii from the Gulf of 

California (Rosas-Alquicira et al., 2013) and the eastern Atlantic 

from the Azores (Rosas-Alquicira et al., 2011); whereas sporangia were found in the center and periphery of the chamber floor 

in Japanese A. zonata (Murata and Masaki, 1978). For now, 

until they can be molecularly tested using type materials, those 

in the Gulf of California are treated as a single species.

Upper Gulf specimens referred to “Amphiroa franciscana

W. R. Taylor” from Bahía Kino (Mendoza-González and MateoCid, 1986) should be reexamined to determine if that species is 

present in the northern Gulf or if they may belong here as well.

Amphiroa brevianceps E. Y. Dawson

Amphiroa brevianceps E. Y. Dawson, 1953a:142, pl. 31: fig. 2; Dawson et al., 1960b:16; Dawson, 1961b:420; Norris and Johansen, 

1981:12, figs. 1b, 6, 9 [type specimen]; Mendoza-González and 

Mateo-Cid, 1986:422; Sánchez-Rodríguez et al., 1989:42; Anderson, 1991:14; Mateo-Cid and Mendoza-González, 1991:19; Dreckmann, 1991:33; Mendoza-González and Mateo-Cid, 1992:17; 

Serviere-Zaragoza et al., 1993a:482; León-Tejera et al., 1993:200; 

León-Tejera and González-González, 1993:496; MendozaGonzález et al., 1994:106; Mateo-Cid and Mendoza-González, 

FIGURE 41. Amphiroa beauvoisii, branch variability: A. Fronds from a single clump. B. A single branch (A, B, JN & HWJ-73-7-3, US 

Alg. Coll.).
9 6 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

1994a:51; González-González et al., 1996:169, 382; RiosmenaRodríguez and Siqueiros-Beltrones, 1996:140; Serviere-Zaragoza 

et al., 1998:171; L. Aguilar-Rosas et al., 2000:130; RiosmenaRodríguez and Woelkerling, 2000:322.

Calcified articulated fronds in small, densely branched 

clumps, up to 4 cm high. Branching more or less regularly dichotomous, in 1 plane. Intergenicula near base subterete or flat 

and up to 2 mm broad, in upper parts flat, short, and broad, up 

to 3 mm broad, usually less than 4 mm long, not differentiated 

(lack midrib and wings). Genicula externally prominent, uncalcified, dark colored, bracketed by calcified extensions of the adjacent intergenicula, 6 or more tiers of cells per geniculum.

Tetrasporangial and carposporangial conceptacles scattered 

over intergenicular surfaces (Dawson, 1953a); protruding above 

intergenicular surface, mostly 300–400 μm in diameter, with a 

small ostiole. Spermatangial conceptacles not reported.

Habitat. On rocks and tidal platforms; low intertidal to shallow subtidal.

Distribution. Gulf of California: El Coloradito to 

Guaymas; Punta Los Frailes; Mazatlán, Sinaloa to Jalisco. Eastern Pacific: Punta San Hipolito, Baja California to Bahía Magdalena Baja California Sur; Colima to Oaxaca.

Type Locality. On rocky shore just east of Salina 

Cruz, Oaxaca, Pacific Mexico.

Remarks. On the basis of morphological comparisons, Amphiroa brevianceps was considered to be conspecific 

with another flattened species also reported in the Gulf of California, the Japanese A. misakiensis (Riosmena-Rodríguez and 

Siqueiros-Beltrones, 1996). Although both have 5 or more tiers 

of medullary cells in the genicula, they can be separated by other 

features: A. brevianceps is erect and mostly regularly branched, 

with similar sized intergenicula throughout, 1.5–3.0 mm wide; 

A. misakiensis is recumbent, irregularly branched, and polymorphic, with irregularly shaped intergenicula that are variable in 

size, up to 7 mm long and mostly 3–4 mm wide. Until comparative molecular analyses are completed on Gulf specimens and the 

Japanese type of A. misakiensis to test their taxonomic status, 

they are herein recognized as separate taxa.

Amphiroa magdalenensis E. Y. Dawson

Amphiroa magdalenensis E. Y. Dawson, 1953a:143 [as “magdalensis”], 

pl. 30: fig. 2; 1959a:21; 1961b:421; Huerta-Múzquiz and TiradoLizárraga, 1970:128; Norris and Johansen, 1981:13, figs. 1c, 6, 10b 

[type specimen]; Stewart and Stewart, 1984:144; Sánchez-Rodríguez 

et al., 1989:42; Anderson, 1991:15; Dreckmann, 1991:33; LeónTejera and González-González, 1993:496; González-González et al., 

1996:171; Riosmena-Rodríguez and Siqueiros-Beltrones, 1996:137; 

Riosmena-Rodríguez and Woelkerling, 2000:326.

Calcified articulated fronds forming loose tufts, up to 5 cm 

high. Branching sparsely, dichotomous or irregular. Intergenicula 

terete near base, others becoming markedly flattened, 1.0–2.5 

mm broad, 3–6 times as long, (3–)7.5–15 mm in length. Genicula conspicuous because of broken out pieces of adjacent intergenicula in center of branch; up to or more than 10 cellular tiers 

per geniculum. 

Tetrasporangial conceptacles scattered on intergenicular 

surfaces, usually more on one side than the other; sexual thalli 

not encountered in the Gulf of California.

Habitat. Shallow subtidal.

Distribution. Gulf of California: Isla de Tortuga 

(about 24.1 km or 15 mi NE of Isla San Marcos) to Isla San 

Ildefonso; Punta Palmilla; Mazatlán. Eastern Pacific: Isla Guadalupe; Punta Abreojos to Isla Santa Margarita (west of Bahía 

Almejas), Baja California Sur; Golfo de Tehuantepec, Oaxaca.

Type Locality. Punta Entrada, Isla Magdalena 

(west side of Bahía Magdalena), Baja California Sur, Pacific 

Mexico.

Remarks. Amphiroa magdalenensis is one of the 

compressed species with characters similar to A. misakiensis, 

and both have been considered to be conspecific by RiosmenaRodríguez and Siqueiros-Beltrones (1996). For now the two are 

recognized as separate species until molecular studies are done to 

test the relationship of Gulf A. magdalenensis to Pacific Mexico 

(type locality) A. magdalenensis and Japanese A. misakiensis.

Amphiroa mexicana W. R. Taylor

Amphiroa mexicana W. R. Taylor, 1945:189, pl. 47; Dawson, 1961b:421; 

Huerta-Múzquiz and Tirado-Lizárraga, 1970:128; Chávez-Barrear, 

1972b:269; Huerta-Múzquiz, 1978:339; Norris and Johansen, 

1981:12, fig. 7a [type specimen]; Huerta-Múzquiz and MendozaGonzález, 1985:50; Mendoza-González and Mateo-Cid, 1985:26; 

Mendoza-González and Mateo-Cid, 1986:422; Salcedo-Martínez et 

al., 1988:83; Dreckmann et al., 1990:30, pl. 5: figs. 5, 6; RiosmenaRodríguez and Siqueiros-Beltrones, 1996:137; Anderson, 1991:15; 

Dreckmann, 1991:33; Mateo-Cid and Mendoza-González, 1992:20; 

Mendoza-González and Mateo-Cid, 1992:18; Serviere-Zaragoza et 

al., 1993a:483; Stout and Dreckmann, 1993:13; León-Tejera et al., 

1993:200; León-Tejera and González-González, 1993:496; MendozaGonzález and Mateo-Cid, 1994:51; González-González et al., 

1996:171; Riosmena-Rodríguez and Siqueiros-Beltrones, 1996:137; 

Riosmena-Rodríguez and Woelkerling, 2000:327; Tejada, 2003:11; 

Hernández-Herrera et al., 2005:147.

Amphiroa peninsularis sensu Taylor, 1945:188 [in part: Guerrero specimens 

only; non Amphiroa peninsularis W. R. Taylor, 1945:188].

Calcified articulated fronds, erect, up to 7 cm tall; densely 

dichotomously, much branched; intergenicula cylindrical to 

compressed of similar diameter throughout, 800–1200 μm in 

diameter; branch tips truncate, 500 μm (or more) in diameter 

(often faint zonal banding visible); intergenicula lengths variable, 

1.5–3.2 mm long, about (0–)1.5–4.0 times as long as wide; genicula dark colored (easily visible), of 4 tiers of medullary cells; 

branching at intervals of 1–3 segments, with branch angles usually less than 45°; arising from small crustose base. Intergenicula 

with relatively thick cortex of 3–5 layers of very small cells; with 

age, increasing up to 6–7 layers and cortical cells elongate anticlinally; multilayered medulla of 3–5 tiers of long cells alternating with a single tier of short cells.

Tetrasporangial and carposporangial conceptacles slightly 

elevated, about 250 μm in diameter, single pore, about 35 μm 

in diameter flush with conceptacle surface. Tetrasporangia, 
NUMBER 96 • 9 7

40–60 μm long borne among paraphyses on cavity floor. Carpospores subspherical, 2528 μm in diameter. Spermatangial conceptacles not known.

Habitat. On rocks, mostly in exposed rocky habitats; intertidal.

Distribution. Gulf of California: Isla Pelícanos 

and Roca Roja, Bahía Kino; Bahía de La Paz; Sinaloa to Jalisco.

Eastern Pacific: Baja California; Guerrero to Oaxaca.

Type Locality. Bahía Petatlán, Guerrero, Pacific 

Mexico.

Remarks. Amphiroa mexicana W. R. Taylor (1945) 

is included herein on the basis of its report in the northern Gulf 

(Mendoza-González and Mateo-Cid, 1986). Dawson (1953a) 

observed it to be locally abundant on the tropical mainland 

coasts of Pacific Mexico. Although similar to A. zonata, A. 

mexicana can be distinguished by its shorter intergenicula and 

more prominent genicula. Norris and Johansen (1981) suggested 

it may be conspecific with A. beauvoisii, and it was later treated 

as a synonym by Riosmena-Rodríguez and Siqueiros-Beltrones 

(1996). The taxonomic status of the northern Gulf A. mexicana 

and its relationships to Pacific Mexico A. mexicana, Eastern Atlantic A. beauvoisii, and Japanese A. zonata from their type localities need to be molecularly tested.

Amphiroa misakiensis Yendo

FIGURE 42

Amphiroa misakiensis Yendo, 1902a:14, pl. 1: figs. 24, 25, pl. 6: fig. 1; 

Yendo, 1902b:6; Norris and Johansen, 1981:15, figs. 1d, 6, 11, 12a, 

13a, 15c [lectotype illustration]; D. S. Choi and Lee, 1988:112, figs. 

4, 8; Riosmena-Rodríguez and Siqueiros-Beltrones, 1991:8; ServiereZaragoza et al., 1993a:483; León-Tejera et al., 1993:200; León-Tejera 

and González-González, 1993:496; Mateo-Cid et al., 1993:46; Stout 

and Dreckmann, 1993:13; Mendoza-González and Mateo-Cid, 1994:51 

Mateo-Cid and Mendoza-González, 1994b:39; Mendoza-González 

et al., 1994:106; León-Álvarez and González-González, 1995:363; 

González-González et al., 1996:171, 383; Anaya-Reyna and RiosmenaRodríguez, 1996:864, tbl. 1; Riosmena-Rodríguez and SiqueirosBeltrones, 1996:140, figs. 20–24 [in part]; Riosmena-Rodríguez and 

Paul-Chávez, 1997:71; Yoshida, 1998:534, fig. 3-13A–F; L. AguilarRosas et al., 2000:130; Mateo-Cid et al., 2000:64; Paul-Chávez and 

Riosmena-Rodríguez, 2000:147; Riosmena-Rodríguez and Woelkerling, 2000:327; Cruz-Ayala et al., 2001:190; CONANP, 2002:139; 

Pacheco-Ruíz and Zertuche-González, 2002:467; López et al., 

2004:10; Riosmena-Rodríguez et al., 2005a:33; Hernández-Herrera et 

al., 2005:147; Mateo-Cid et al., 2006:51, 55; Serviere-Zaragoza et al., 

2007:9; Pacheco-Ruíz et al., 2008:208; Y.-P. Lee, 2008:187, figs. A–C; 

Fernández-García et al., 2011:60; Rosas-Alquicira et al., 2013:698, 

figs. 9, 11–13, 20–24, tbls. 1, 2.

Amphiroa pusilla sensu Dawson, 1944a:276 [in part; not Amphiroa pusilla

Yendo, 1902a:13]. 

Amphiroa dimorpha sensu Taylor, 1945:192, pl. 55; Dawson, 1953a:141; 

1957c:19; Dawson et al., 1960a:44 pl. 23: fig. 5; 1960b:16; Dawson, 

1961b:420; 1961c:411; Dawson et al., 1964:47; Dawson, 1966a:18; 

Huerta-Múzquiz, 1978:337, 339; Pedroche and González-González, 

1981:66; Tittley et al., 1984:5; Mendoza-González and Mateo-Cid, 

1986:422; Salcedo-Martínez et al., 1988:83; Sánchez-Rodríguez et 

al., 1989:42; Dreckmann et al., 1990:30; Mateo-Cid and MendozaGonzález, 1991:19; Dreckmann, 1991:33; Mendoza-González and 

Mateo-Cid, 1992:17; Mateo-Cid and Mendoza-González, 1992:20; 

León-Tejera et al., 1993:200; Serviere-Zaragoza et al., 1993a:482; 

Mendoza-González et al., 1994:106; Mateo-Cid and MendozaGonzález, 1994b:39; Mateo-Cid et al., 2000:64; Riosmena-Rodríguez 

and Woelkerling, 2000:324; Hernández-Herrera et al., 2005:147 [non 

Amphiroa dimorpha Me. Lemoine, 1930:76].

Amphiroa dimorpha var. digitiformis E. Y. Dawson, 1959a:21, as “digitiforme”; 1961b:420; Espinoza-Avalos, 1993:333; González-González et 

al., 1996:170; Riosmena-Rodríguez and Siqueiros-Beltrones, 1996:140; 

Riosmena-Rodríguez and Woelkerling, 2000:324.

Fronds up to 4 cm tall; erect or more or less recumbent; 

branching dichotomous to trichotomous, but this pattern often 

obscure when adventitious branches arise irregularly from intergenicula; with flat and rounded apices; attached by discoid 

crustose holdfast. Intergenicula near base small and subcylindrical; in upper parts of fronds flat, irregularly shaped, size varying 

greatly but usually 3–4 mm wide and up to 7 mm long; of 2–6 

rows of long cells alternating with 1 short cell; cortex of 23–25 

FIGURE 42. Amphiroa misakiensis: A. Irregular branching patterns (JN-3674, US Alg. Coll.). B. Branches with conceptacles (JN-3684 US Alg. 

Coll.). C. Numerous small branches arising from some of the large flat intergenicula (JN-5102, US Alg. Coll.). 
9 8 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

squarish cortical cells; trichocytes rare. Genicula developed by 

cracking and sloughing of calcified cortical tissue overlying genicular tissue; composed of 5–8 tiers of cells, with patches of 

uncalcified cortical tissue.

Conceptacles immersed in cortex scattered over uppermost 

intergenicula surfaces (or lowermost according to Dawson, 

1953a:142) and protruding; verrucose appearance to branch intergenicula with gametangia; pore formed by coalition of two 

roof filaments. Tetrasporangial and bisporangial conceptacles 

oblong, (175–)200–300 μm inside diameter; with scattered paraphyses. Sporangial conceptacle canal with large block cells 

(Rosas-Alquicira et al., 2013); sporangia in center and periphery of cavity floor. Carposporangial conceptacles oblong to verrucose, up to 200 μm inside diameter; carpogonial filaments 

develop from margins of fusion cell (Riosmena-Rodríguez and 

Siqueiros-Beltrones, 1996) or its entire surface (Rosas-Alquicira 

et al., 2013). Spermatangial conceptacles verrucose, 75–125 μm 

inside diameter; spermatangia simple, borne on cavity floor.

Habitat. Low intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabo San Lucas; Mazatlán, Sinaloa to Jalisco; Isla María 

Cleofa (Islas Marías; Islas Tres Marías). Eastern Pacific: Isla Cedros (Baja California); Chester Islets (NE of Punta Falsa), Bahía 

Sebastián Vizcaíno to Todos Santos, Baja California Sur; Isla 

Socorro and Isla San Benedicto (Islas Revillagigedo); Jalisco to 

Oaxaca; El Salvador to Costa Rica; Panama; Peru. Western Pacific: Japan; Korea.

Type Locality. Misaki, Sagami Bay, Kanagawa 

Prefecture, Honshū, Japan.

Remarks. See also Remarks under Amphiroa 

brevianceps.

Amphiroa rigida J. V. Lamouroux

Amphiroa rigida J. V. Lamouroux, 1816:297, pl. 11: fig. 1; Yendo, 1902a:6, 

pl. 1: figs. 5, 6, pl. 4: fig. 4; Norris and Johansen, 1981:19, figs. 1e, 

6a, 14a, 14c; Garbary and Johansen, 1987:3, fig. 10; Mateo-Cid et 

al., 1993:46; Serviere-Zaragoza et al., 1993a:483; León-Tejera et al., 

1993:200; Stout and Dreckmann, 1993:13; Mateo-Cid and MendozaGonzález, 1994b:39; Mendoza-González and Mateo-Cid, 1994:51; 

Mendoza-González et al., 1994:106; González-González et al., 

1996:302; Riosmena-Rodríguez and Siqueiros-Beltrones, 1996:137, 

figs. 6–9; Riosmena-Rodríguez and Paul-Chávez, 1997:71; Yoshida, 

1998:537; Abbott, 1999:178, figs. 44D, 45C; Paul-Chávez and 

Riosmena-Rodríguez, 2000:147; Riosmena-Rodríguez and Woelkerling, 2000:330; CONANP, 2002:139; López et al., 2004:10; MateoCid et al., 2006:51, 55; Serviere-Zaragoza et al., 2007:9; Bernecker 

and Wehrtmann, 2009:225; Fernández-García et al., 2011:60; RosasAlquicira et al., 2013:698, fig. 48, tbl. 2.

Amphiroa rigida var. antillana Børgesen, 1917:182, figs. 171–173; RiosmenaRodríguez and Siqueiros-Beltrones, 1996:137; Riosmena-Rodríguez 

and Woelkerling, 2000:321.

Fronds up to 3 cm high, erect and isolated or sometimes in 

more or less erect clumps; attached by crustose holdfast. Branching alternately pinnate to irregular, sometimes dichotomous, and 

usually at wide angles, branch junctions usually not coinciding 

with genicula; branches with rounded apices. Intergenicula mostly 

cylindrical, occasionally subcylindrical, 0.4–1.0 mm diameter and 

variable in length; of 1–3 rows of long cells alternating with 1 row 

of short cells; cortex of 6 tiers of rounded cortical cells. Genicula 

often nearly invisible in young parts of fronds, becoming visible by 

separation of adjacent calcified segments; of 2 tiers of medullary 

cells, without cortication; cell wall ends mostly imbricate.

Tetrasporangial and bisporangial conceptacles embedded in 

cortex of the intergenicula, oblong cavities, 150–175 μm inside 

diameter, with scattered paraphyses; sporangia in center and periphery of chamber floor; chamber pore canal with block-shaped 

cells. Gametangial conceptacles embedded in the cortical cells 

of intergenicular margins; protruding, giving surface a verrucose 

appearance; with pores developed in cavity roof by repeated upward divisions of cortical cells, coalescing upward. Carpogonial 

conceptacles oblong to elliptical, 100–150 μm inside diameter; 

carpogonial filaments develop from entire surface of fusion cell. 

Spermatangial conceptacles oblong, 150–160 μm inside diameter; spermatangia simple, borne on cavity floor.

Habitat. On rocks; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco; 

Bahía Concepción to Cabeza Ballena; Mazatlán, Sinaloa to 

Jalisco; Isla María Magdalena (Islas Marías; Islas Tres Marías). 

Eastern Pacific: Playa Los Cerritos (south of Todos Santos), Baja 

California Sur; Isla Socorro and Isla San Benedicto (Islas Revillagigedo); Jalisco to Michoacán; Costa Rica; Nicaragua. Central 

Pacific: Hawaiian Islands. Western Pacific: Japan.

Type Locality. Mediterranean Sea (“Mediterranee”; Lamouroux, 1816:297).

Remarks. Some smaller specimens of Gulf Amphiroa 

rigida could be confused with A. valonioides. Amphiroa rigida

may be distinguished from A. valonioides by its rigid branches, 

which are irregular placed and usually not formed at the genicula, as in other species of Gulf Amphiroa. Also A. rigida is the 

only species of Amphiroa in the Gulf with unique imbricate end 

walls of the genicular cells (cf. Norris and Johansen, 1981: fig. 

14c). Reproductive and vegetative anatomy of Mediterranean 

specimens of A. rigida was studied by Suneson (1937). The Gulf 

A. rigida should be morphologically and molecularly tested with 

Mediterranean type material of A. rigida to resolve its phylogenetic and taxonomic status.

Amphiroa taylorii E. Y. Dawson

Amphiroa taylorii E. Y. Dawson, 1953a:138, pl. 26: fig. 1 [type specimen]; 1954b:137; 1957c:19; 1959a:22; 1961b:421; 1966a:18; 

Huerta-Múzquiz and Tirado-Lizárraga, 1970:128; Huerta-Múzquiz 

and Garza-Barrientos, 1975:8, 11; Mendoza-González and MateoCid, 1986:422; Sánchez-Rodríguez et al., 1989:42; Mateo-Cid and 

Mendoza-González, 1991:19; Anderson, 1991:15; Mendoza-González 

and Mateo-Cid, 1992:18; Serviere-Zaragoza et al., 1993a:483; 

González-González et al., 1996:172; Riosmena-Rodríguez and 

Siqueiros-Beltrones, 1996:137; Riosmena-Rodríguez and Woelkerling, 

2000:331; Bernecker, 2009:CD-Rom p. 59.

Amphiroa annulata sensu Taylor, 1945:188 [in part; Isla Socorro material 

only; non Amphiroa annulata Me. Lemoine, 1930:78].
NUMBER 96 • 9 9

Algae of tufts, up to 1.5 cm tall, of erect, more or less 

straight to curved axes; unbranched to sparsely dichotomously 

branched above; irregular, multifariously or pinnately branched 

below axes from a crustose base. Axes and branches cylindrical, 250–450 m in diameter, intergenicula usually crocked, not 

uniform in diameter throughout (portions irregular in diameter); 

cortex of 6–8 cortical cell layers. Intergenicula (2–)6–15 times 

longer than wide (500–)1200–5000 μm in length; prominently 

constricted at genicula. Genicula usually of 2 tiers of medullary cells; cell ends may be imbricated (cf. Norris and Johansen, 

1981: fig. 14c).

Habitat. On rocks; intertidal to shallow subtidal, 

down to 2 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to Puerto Escondido; Cabeza Ballena; Nayarit to Jalisco; Isla 

María Magdalena (Islas Marías; Islas Tres Marías). Eastern Pacific: Bahía Magdalena, Baja California Sur; Isla Socorro (Islas 

Revillagigedo); Jalisco to Colima; Costa Rica.

Type Locality. On intertidal rocks; Bahía Braithwaite, Isla Socorro, Islas Revillagigedo, Pacific Mexico.

Remarks. Dawson (1959a) noted southern Gulf Amphiroa taylorii were more regularly dichotomously branched than 

the Pacific Mexico type specimen and had cylindrical branches 

with constricted two-tiered genicula with smooth cells wall ends.

Amphiroa taylorii has been considered a synonym of 

A. rigida, another species with two tiers of genicular cells (Norris and Johansen, 1981; Riosmena-Rodríguez and SiqueirosBeltrones, 1996). Although the imbricate nature of the genicula 

cell wall ends was used to separate A. rigida (Norris and Johansen, 1981), Riosmena-Rodríguez and Siqueiros-Beltrones (1996) 

noted their southern Gulf specimens of A. rigida to have both 

smooth and imbricate cell wall ends in the genicula. The relationship of these two species should be reconsidered. Critical 

morphologically and molecular studies are needed that compare 

Gulf specimens with type locality materials of A. taylorii and 

A. rigida to resolve their taxonomic status.

Amphiroa valonioides Yendo

FIGURE 43

Amphiroa valonioides Yendo, 1902a:5, pl. 1: figs. 1–3, pl. 4: fig. 1; Norris and Johansen, 1981:20, figs. 1f, 6, 12d, 13b, 15a, 16, 17 [lectotype]; Johansen, 1981:68: fig. 10C; Stewart, 1982:54; Stewart and 

Stewart, 1984:144; D. S. Choi and Lee, 1988:112, figs. 9A–D; 

Dreckmann, 1991:33; León-Tejera et al., 1993:200; Mateo-Cid et 

al., 1993:46; Serviere-Zaragoza et al., 1993a:483; Mateo-Cid and 

Mendoza-González, 1994b:39; Mendoza-González and Mateo-Cid, 

1994:51; Mendoza-González et al., 1994:106; González-González 

et al., 1996:172, 384; D. S. Choi and Lee, 1996:269, figs. 3–4; 

Riosmena-Rodríguez and Siqueiros-Beltrones, 1996:136, figs. 2–5; 

Riosmena-Rodríguez and Paul-Chávez, 1997:71; Yoshida, 1998:537; 

Serviere-Zaragoza et al., 1998:171; Abbott, 1999:180, figs. 44E, 45D; 

L. Aguilar-Rosas et al., 2000:130; Mateo-Cid et al., 2000:64; PaulChávez and Riosmena-Rodríguez, 2000:147; Riosmena-Rodríguez 

and Woelkerling, 2000:332; Cruz-Ayala et al., 2001:190; CONANP, 

2002:139; Pacheco-Ruíz and Zertuche-González, 2002:467; Abbott 

et al., 2002:302; López et al., 2004:10; Mateo-Cid et al., 2006:51, 

55; Serviere-Zaragoza et al., 2007:9; Pacheco-Ruíz et al., 2008:208; 

Castañeda-Fernández de Lara et al., 2010:199; Fernández-García et al., 

2011:60; Rosas-Alquicira et al., 2013:698, tbl. 2.

Amphiroa annulata Me. Lemoine, 1930:78, fig. 34, pl. 4: fig. 1; Taylor, 

1945:188; Dawson, 1953a:136, pl. 29: fig. 3; 1959a:20; 1961b:420; 

1966a:18; Chávez-Barrear, 1972b:269; Stewart, 1982:54; Tittley et al., 

1984:4; Sánchez-Rodríguez et al., 1989:42; Mateo-Cid and MendozaGonzález, 1992:20; González-González et al., 1996:169, 382; Lamy 

and Woelkerling, 1998:140; Riosmena-Rodríguez and Woelkerling, 

2000:321; Bernecker, 2009:CD-Rom p. 59.

FIGURE 43. Amphiroa valonioides: A. Habit, tuft of fronds (JN-3146, US Alg. Coll.). B. Longitudinal section showing geniculum of a single 

tier of cells (JN & HWJ-73-7-4, US Alg. Coll.). C. Branches separated from the tuft; note the protruding conceptacles (JN & HWJ-73-7-33, US 

Alg. Coll.).
100 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Amphiroa annulata var. pinnata E. Y. Dawson, 1953a:137; 1957:19, with 

query; 1959a:20; 1961b:420; Anderson, 1991:14; González-González 

et al., 1996:169; Riosmena-Rodríguez and Woelkerling, 2000:328.

Fronds mostly 1–2 cm high (occasionally up to 3), more 

or less erect clumps or turfs, branching dichotomous to oppositely pinnate; branch apices cylindrical and rounded; attached 

by crustose holdfast. Intergenicula cylindrical or rarely compressed, mostly less than 0.5 mm diameter (rarely more) and 1–3 

mm long; of 1–3 rows of long cells that alternate with 1 row of 

short cells; cortex of 2–3 tiers of rectangular cells. Genicula of 

only 1 tier of cells; fully formed genicula barely visible in terete 

branches, more easily visible in compressed branches; secondary 

pit connections present between genicula cells.

Conceptacles often in a single row on intergenicula, protruding markedly; pore formed by degeneration of roof epithelial cells. Tetrasporangial and bisporangial conceptacles, oblong, 

200–300 μm inside diameter; sporangial canal pore with blockshaped cell. Carposporangial conceptacles oblong, 150–250 μm 

inside diameter; carpogonial filaments develop from entire surface of fusion cell. Spermatangial conceptacles unknown. 

Habitat. Often in sand-filled turfs, on rocks and 

tidal platforms; high to mid intertidal, occasionally in shallow 

subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabo Pulmo; Mazatlán. Eastern Pacific: Isla Guadalupe; Baja 

California to Panama. Central Pacific: Hawaiian Islands. Western Pacific: Japan; Korea; Taiwan; Vietnam.

Syntype Localities. Two localities in Japan were 

listed by Yendo (1902b:5): Province Hiuga (Hyūga) (now Miyazaki Prefecture), Kyûshû Island, and Misaki (Sagami Bay, 

Kanagawa Prefecture), Honshū Island. 

Remarks. Amphiroa valonioides is a warm temperate to tropical species. A common species of the intertidal, A. 

valonioides is most abundant in the winter and spring in the 

northern Gulf. It can be distinguished from similar forms of 

small A. beauvoisii by its genicula of a single row of medullary 

cells and its more conspicuous, protruding conceptacles.

 Although considered a synonym of A. valonioides (Norris 

and Johansen, 1981), the Gulf of California A. annulata var. pinnata E. Y. Dawson (1953a; type locality: Cabeza Ballena, Baja 

California Sur) should be reexamined and its taxonomic status 

tested with molecular phylogenetic comparisons to the types and 

type locality specimens of A. valonioides (Japan) and A. annulata Me. Lemoine (Isla Santiago, Galápagos Islands). 

Amphiroa vanbosseae Me. Lemoine

FIGURE 44

Amphiroa vanbosseae Me. Lemoine, 1930:73, fig. 30, pl. 3: fig. 7; Taylor, 

1945:192; Dawson, 1961b:421; Norris and Johansen, 1981:23, figs. 

1g, 4d, 6, 10a, 12b,c, 13c, 18; Littler and Littler, 1984:22; Tittley et al., 

1984:5; Norris, 1985d:208; Dreckmann, 1991:33; Serviere-Zaragoza 

et al., 1993a:483; Mateo-Cid et al., 1993:46; Mendoza-González 

and Mateo-Cid, 1994:51; González-González et al., 1996:385; 

Riosmena-Rodríguez and Siqueiros-Beltrones, 1996:138, figs. 15–19; 

Riosmena-Rodríguez and Paul-Chávez, 1997:71; Lamy and Woelkerling, 1998:140; Rodríguez-Morales and Siqueiros-Beltrones, 1999:23; 

Mateo-Cid et al., 2000:64; Aguilar-Rosas et al., 2000:131; PaulChávez and Riosmena-Rodríguez, 2000:147; Riosmena-Rodríguez 

and Woelkerling, 2000:332; Cruz-Ayala et al., 2001:190; CONANP, 

2002:139; Pacheco-Ruíz and Zertuche-González, 2002:467; RiveraCampos and Riosmena-Rodríguez, 2003:59; Mateo-Cid et al., 

2006:51, 56; Pacheco-Ruíz et al., 2008:208; Rosas-Alquicira et al., 

2013:698, figs. 7, 14, 27, 34, 40–47, 49–51, tbls. 1, 2. 

Amphiroa rigida sensu Dawson, 1944a:276 [non Amphiroa rigida Lamouroux, 1816:297].

Amphiroa subcylindrica E. Y. Dawson, 1953a:139, pl. 29: fig. 1; 1959a:10, 

22; 1966a:18; Huerta-Múzquiz, 1978:338; Littler and Littler, 

1981:151, 153–154; Johansen, 1981:68: fig. 10A; Huerta-Múzquiz 

and Mendoza-González, 1985:50; Mendoza-González and MateoCid, 1986:422; Salcedo-Martínez et al., 1988:83; Anderson, 1991:15; 

González-González et al., 1996:172, 383; Riosmena-Rodríguez and 

Woelkerling, 2000:330; Fernández-García et al., 2011:60.

Calcified articulated fronds up to 10 cm high, more or less 

erect, often in clumps; initially attached by a discoid holdfast, later 

becoming an expanding crustose holdfast. Branching dichotomous 

to trichotomous or sometimes polychotomous and becoming obscure and irregular; branches with rounded apices. Intergenicula cylindrical to subcylindrical, 1–2 mm diameter and variable in length, 

up to or more than 1.0 cm (length difficult to discern because genicula thickening with age are often barely visible); of 2–5 rows of 

long cells alternating with 1 row of short cells; cortex of 9 bands 

of oblong cortical cells. Genicula uncalcified, consisting of (4–)5–8

(–10) tiers of cells; fully formed genicula often barely visible between 

intergenicula near branch apices, becoming apparent by cracking 

and sloughing of calcified cortical tissue overlying intergenicula.

Conceptacles scattered over intergenicular surfaces, protruding only slightly, becoming buried by continuing cortical 

growth; pore formed by the coalescent repeated division of roof 

cells, oriented toward the margin. Tetrasporangial and bisporangial conceptacles 200–300 μm inside diameter. Sporangial 

conceptacle canal with large block cells; sporangia in center and 

periphery of cavity floor. Carpogonial filaments develop only on 

margins of fusion cell. Basal cells of spermatangial conceptacle 

form by basal division of cavity cells; each basal cell produces 

2 spermatangial parent cells that develop simple spermatangial 

filaments; spermatangia release spermatia that fill conceptacle 

chamber (reproduction after Rosas-Alquicira et al., 2013).

Habitat. Low intertidal to subtidal; on rocks.

Distribution. Gulf of California: Puerto Peñasco 

to Punta Palmilla; Nayarit to Jalisco. Eastern Pacific: Panama; 

Galápagos Islands.

Type Locality. “Recueillie juste audessous de la 

limite de la mer” (Lemoine, 1930:73); Bahía Correos (Post Office Bay), Isla Floreana (Isla Charles; Isla Santa María), Islas 

Galápagos, Ecuador.

Remarks. Temporal and spatial studies of Amphiroa 

vanbosseae at El Sargento in the southern Gulf (Rivera-Campos 

and Riosmena-Rodríguez, 2003) showed the species occurred 

throughout the year, with the largest thalli found in spring. Reproduction was throughout the year. The highest proportion of 
NUMBER 96 • 101

reproductive thalli (mostly bisporangia and tetrasporangia) was 

found in summer when other algal species decreased or disappeared, presumably because of environmental stress.

Norris and Johansen (1981), on the basis of morphological 

comparisons, concluded the northern Gulf of California A. subcylindrica E. Y. Dawson (1953a; type locality: Punta Colorado, 

near Guaymas, Sonora) was conspecific with the Galápagos 

A. vanbosseae (see also Riosmena-Rodríguez and SiqueirosBeltrones, 1996). It will be interesting to test if comparative molecular analyses could confirm their taxonomic status.

Corallinaceae subfam. Lithophylloideae

Corallinaceae subfam. Lithophylloideae Setchell, 1943:134, as ‘Lithophylleae’; Cabioch, 1972:261, 266; Harvey et al., 2003a:994.

The subfamily Lithophylloideae is characterized by genera 

that have thalli without genicula and that vary in form from 

horizontally flattened crusts to being composed mainly of protuberances. Crustose portions internally dorsiventrally organized, 

protuberances, when present, more or less radially organized. 

Some cells of contiguous vegetative filaments with secondary 

pit connections adjoining them; cell fusions are absent or rare. 

Sporangial conceptacles produced by filaments peripheral to 

the fertile area and interspersed among sporangial initials. Spermatangial filaments develop from the spermatangial conceptacle 

floor. 

Remarks. If Cabioch (1972) is followed with C. subfam. Amphiroideae treated within C. subfam. Lithophylloideae, 

it would include the articulated genus Amphiroa in addition to 

its nonarticulated (crustose) members. (See also Remarks under 

C. subfam. Amphiroideae.)

There are four genera represented in the northern Gulf of 

California. Two of these, tentatively placed in C. subfam. Lithophylloideae, remain problematic. Litholepis requires further 

FIGURE 44. Amphiroa vanbosseae: A. Habit (holotype of Amphiroa subcylindrica E. Y. Dawson, EYD-555, AHFH-4277, now UC). B. Branch 

intergenicula with conceptacles (JN & HWJ-73-7-1, US Alg. Coll.). C. Coarse cylindrical intergenicula of branches (JN-3050, US Alg. Coll.).
102 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

elucidation of its generic status, and Pseudolithophyllum, although traditionally included, appears not to belong in this subfamily on the basis of its morphological features. It too needs 

testing of its generic status and taxonomic position.

KEY TO THE GENERA OF CORALLINACEAE SUBFAM. LITHOPHYLLOIDEAE 

IN THE NORTHERN GULF OF CALIFORNIA

1a. Crusts thin, a single cell layer; on rocks, shells, or other corallines; individuals usually overgrowing each other to form 

2–4 layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Litholepis

1b. Crusts thicker, of 2 or more cell layers; epiphytic, epilithic, or partly to entirely unattached and nodular (rhodoliths) . . . 2

2a. Crusts of Gulf species epiphytic (somewhat loosely surrounding algal host), with smooth to irregular surfaces; primigenous (basal) filaments composed of palisade cells (vertically elongated) . . . . . . . . . . . . . . . . . . . . . . . . . . Titanoderma

2b. Gulf crustose species epilithic or partly to entirely free living nodules (rhodoliths), with protuberances of various sizes and

shapes; primigenous filaments mostly to entirely composed of nonpalisade cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Secondary pit connections present between some cells of contiguous filaments; intercellular fusions absent to rare, crustose portions with uni- or multistratose primigenous (basal) layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lithophyllum

3b. Secondary pit connections lacking; intercellular fusions present linking some cells of contiguous filaments ; crustose portions with unistratose primigenous layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pseudolithophyllum

Litholepis Foslie

Litholepis Foslie, 1905b:5.

Melobesia subgen. Litholepis (Foslie) Me. Lemoine, 1917:154, 176.

Calcified crusts are thin and delicate; composed of a single 

cell layer (except around the conceptacles). Monostromatic layer 

of thick-walled cells. Typically, overgrowth of a single crust by 

several other individuals results in a structure of 2–4 cell layers. 

Species mostly grow on rocks or shells.

Sporangial conceptacles protrude above surface and have a 

single pore (at least in Gulf of California L. sonorensis).

Remarks. Woelkerling (1986; 1988) concluded the 

lectotype of the genus, Litholepis caspica (Foslie) Foslie (1905b; 

basionym: Melobesia caspica Foslie, 1900a), belonged in the 

genus Titanoderma, as T. capsicum (Foslie) Woelkerling (1986). 

Later T. capsicum was considered conspecific with T. pustulatum 

(Foslie) Nägeli (in Nägeli and Cramer, 1858; see Chamberlain, 

1991), and subsequently with Lithophyllum pustulatum (J. V. 

Lamouroux) Foslie (1904; see Woelkerling and Campbell, 1992). 

Although Campbell and Woelkerling (1990) and Woelkerling 

(1996b) treated Titanoderma as congeneric with Lithophyllum, 

Titanoderma has been maintained by Chamberlain and Irvine 

(1994a; see Chamberlain et al., 1991). Molecular and morphological analyses are needed to elucidate species of Litholepis, 

their generic placement, and relationship to the Lithophyllum–

Titanoderma complex (Bittner et al. 2011; see also Remarks 

under Titanoderma).

Currently, one species of Litholepis is recognized in the Gulf 

of California. However, its generic status is uncertain.

Litholepis sonorensis E. Y. Dawson

FIGURE 45A

Litholepis sonorensis E. Y. Dawson, 1944a:275, pl. 63: fig. 1; 1960b:59, pl. 

48: fig. 1; 1961b:417; Anderson, 1991:31; Espinoza-Avalos, 1993:333; 

González-González et al., 1996:237, 400; Riosmena-Rodríguez and 

Paul-Chávez, 1997:71; L. Aguilar-Rosas et al., 2000:131; RiosmenaRodríguez and Woelkerling, 2000:345; Fragoso and Rodríguez, 

2002:107.

Lithophyllum sonorensis (Dawson) Woelkerling ex Dreckmann, 1991:34, 

comb. inval.; León-Álvarez and González-González, 1993:462; 

González-González et al., 1996:401; Fragoso and Rodríguez, 2002: 

105, 106, 113.

Crusts thin, delicate, gray-white, spreading; 1 cell layer in 

vegetative portions; thicker at conceptacle, 2–4 cell layers when 

thalli overgrow each other; cell layer of rectangular cells, variable in height, 11–25(–28) μm tall and 14–19 μm wide.

Sporangial conceptacles more or less conical, about 350–

400 μm outside diameter; only slightly protruding, up to 60 μm 

above crust surface; with a single pore; conceptacle 175 μm tall, 

300 μm inside diameter; with flat floor of single cell layer and 

roof of (1–)2–3 cell layers; tetrasporangia relatively small, approximately 50 μm long, 20 μm wide. Gametangial conceptacles 

unknown.

Habitat. On old mollusk shells; subtidal, dredged.

Distribution. Gulf of California: Canal de San 

Lorenzo, off Isla Espíritu Santo. Eastern Pacific: Zihuatanejo, 

Guerrero.

Type Locality. Dredged from 12–25 m depths; 

Canal de San Lorenzo (off the southern end of Isla Espíritu Santo), 

Bahía de La Paz, Baja California Sur, Gulf of California, Mexico.

Remarks. Litholepis sonorensis is only known from 

the type and its report in tropical Pacific Mexico from Guerrero. 

It is included herein in the hopes that it will again be collected, 

reevaluated, and tested to resolve its taxonomic status.

Lithophyllum Philippi

Lithophyllum Philippi, 1837:387.

Calcified crustose algae, usually found growing on varioussized rocks or shells and sometimes surrounding pebbles or 

forming free-lying nodules (rhodoliths). Members of the genus 

display a variety of forms from thin crusts to stony rhodoliths 
NUMBER 96 • 103

thick with protuberances of various sizes and shapes. Internal 

structure is pseudoparenchymatous, and construction is monomerous, dimerous, or both. A monomerous thallus consists of 

a single system of branched filaments that form a ventral and/

or central core and a peripheral area when portions of the core 

filaments shift outward toward the thallus surface. A dimerous thallus consists of two groups of filaments—a single layer 

of primigenous filaments (hypothallium) composed of squarish 

(nonpalisade) cells and a second order of filaments (postigenous) 

produced from the dorsal side of the basal (primigenous) filament cells—which grow perpendicular to the basal/ventral layer 

filaments. Secondary pit connections are present between some 

cells of contiguous filaments. Intercellular fusions are absent, 

and trichocytes are absent to rare. 

Sporangial conceptacles open by a single pore, internally 

with bisporangia or tetrasporangia scattered across conceptacle 

chamber floor or with a raised central columella containing a 

tuft of sterile filaments, with the sporangia restricted to the periphery of the chamber. Sporangial conceptacles produced by 

filaments peripheral to the fertile area and interspersed among 

sporangial initials. Gametophytes are usually dioecious; carposporangial and spermatangial conceptacles are also uniporate. 

Unbranched spermatangial filaments are developed from the 

conceptacle chamber floor. 

Remarks. Two species described from Bahía de La 

Paz in the southern Gulf of California have been excluded from 

the genus (Riosmena-Rodriguez et al., 1999). Though their generic 

placement was unresolved, Riosmena-Rodriguez and Woelkerling 

(2000) noted that Lithophyllum californiense Heydrich (1901b; 

treated as synonym of L. pallescens by Dawson, 1960a) belongs 

in Hapalidiaceae subfam. Melobesioideae; and L. brachiatum

(Heydrich) Me. Lemoine (1930; basionym: L. lithophylloides 

f. brachiatum Heydrich, 1901b; considered a synonym of L. lithophylloides by Dawson, 1960a) belongs in either Corallinaceae 

subfam. Mastophoroideae or H. subfam. Melobesioideae. 

Two other species have also been reported in the southern 

Gulf. Lithophyllum corallinae (P. Crouan et H. Crouan) Heydrich (1897b; basionym: Melobesia corallinae P. Crouan et 

H. Crouan, 1867) was reported by Dawson (1960b, as Dermatolithon corallinae (P. Crouan et H. Crouan) Foslie, 1909) and 

by Serviere-Zaragoza et al. (1993a, as Titanoderma corallinae

(P. Crouan et H. Crouan) Woelkerling, Chamberlain et P. C. 

Silva, 1985), and L. lichenare L. R. Mason (1953), a species that 

Riosmena-Rodríguez and Woelkerling (2000) noted requires 

further study, is recorded from Bahía Concepción (Mateo-Cid 

et al., 1993) and Mazatlán (Mendoza-González et al., 1994) 

and in Pacific Mexico from Baja California (R. Aguilar-Rosas 

and Aguilar-Rosas, 1994), Islas Revillagigedo (Huerta-Múzquiz 

and Garza-Barrientos, 1975), Nayarit and Jalisco (MendozaGonzález and Mateo-Cid, 1992; Serviere-Zaragoza et al., 

1993a), and Michoacán (Stout and Dreckmann, 1993).

Rhodoliths were known as “chicaron” on the former pearlfishing banks around La Paz (Dawson, 1944a). Living rhodolith or maerl (maërl) beds are unique marine ecosystems, widely 

distributed but particularly abundant in the Gulf of California, 

the Pacific off southern Japan, Atlantic waters off the coasts of 

Norway, Ireland, Scotland, northeast Canada, eastern Caribbean 

and Brazil, the Mediterranean and Red Seas, and Indian Ocean 

off the coast of western Australia (Foster, 2001; Amado-Filho et 

al., 2012). In the Gulf of California, rhodolith beds are often extensive, occurring from Puerto Peñasco, Sonora, to Islas Marietas, Jalisco (Foster et al., 1997; Riosmena-Rodríguez et al., 2010: 

fig. 3.1). With their high ecological and economic value they are 

now recognized as critical habitats in need of monitoring and 

FIGURE 45. Species of Litholepis and Heteroderma. A. Litholepis sonorensis: Transection through a tetrasporangial conceptacle (EYD592x-40, type AHFH, now UC). B. Heteroderma corallinicola: Transection through tetrasporangial conceptacle (Drouet & Richards-338a, 

type AHFH, now UC).
104 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

conservation (Ávila and Riosmena-Rodríguez, 2010; RiosmenaRodríguez et al., 2010).Six species of Lithophyllum are recognized to occur in the 

northern Gulf of California.

KEY TO THE CRUSTOSE AND RHODOLITH-FORMING SPECIES OF LITHOPHYLLUM,

PSEUDOLITHOPHYLLUM, AND NEOGONIOLITHON IN THE NORTHERN GULF OF CALIFORNIA

1a. Crusts with lateral cell fusions between cells of filaments; secondary pit connections absent . . . . . . . . . . . . . . . . . . . . 2

1b. Crusts without cell fusions between cells of filaments; secondary pit connections present . . . . . . . . . . . . . . . . . . . . . . . 3

2a. Crusts usually thin (some thicker); with low (up to 2 mm tall), short subspherical protuberances; sporangial conceptacles 

less than 250 μm in diameter; trichocytes absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pseudolithophyllum neofarlowii

2b. Crusts with prominent (up to 15 mm tall), subcylindrical to compressed, longer protuberances; sporangial conceptacles 

in apex of protuberances, large, up to 1000 μm in diameter; trichocytes present . . . . . . . Neogoniolithon trichotomum

3a. Rhodoliths either flat, broad fan-like to blade-like excrescences, with rounded edges, OR protuberant branches with 

broad compressed to flattened portions with angular branches that narrow to pointed apices . . . . . . . . . . . . . . . . . . . . 4

3b. Crusts or rhodoliths with slender subcylindrical branches to wart-like knobby protuberances (not flat or blade-like) . . . 5

4a. Rhodoliths predominantly fan-like to blade-like, of thin, broad flat, sometimes undulate, excrescences, some with ridges 

or channels and rounded edges . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. diguetii

4b. Rhodoliths with compressed to somewhat flattened portions; angular branches mostly narrowing upward to irregularly 

pointed apices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. margaritae

5a. Crusts with low, irregularly undulating surface; or, surface with simple, short (mostly 2–5 mm tall), subspherical or 

mound-like protuberances; base subcylindrical to broad; ends broad, irregularly rounded . . . . . . . . . . . . . . . L. imitans

5b. Crusts or rhodoliths either with taller, larger, more elaborate protuberant branches, or wart-like or knob-like protuberances; ends flattened or rounded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6a. Crusts shrubby with clusters of irregularly branched, subcylindrical, often anastomosed branches, but free in upper parts; 

wider at base, upward becoming slender (1.5 mm or less in diam.) with rounded or truncate tops . . . . . . . L. hancockii

6b. Crust or rhodoliths with stout wart-like or knob-like protuberances with rounded or broad, flattened tops (equal to or 

over 2 mm diam.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

7a. Crusts or rhodoliths with simple or forked, compressed to knob-like protuberances (up to 3 cm tall); mostly narrow bases 

(to 3 mm in diameter) widened upward, with truncate, broad flattened ends (4–5 or more mm wide), often with a central 

depression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. proboscideum

7b. Crusts and rhodoliths lumpy and knobby, with short (mostly less than 1.5 cm tall), simple, knob- to club-shaped protuberances (2–4 mm in diameter), with rounded to bulbous, slight to conspicuous swollen ends (not flattened) . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. pallescens

Lithophyllum diguetii (Hariot) Heydrich

FIGURE 46

Lithothamnion diguetii Hariot, 1895:167; Heydrich, 1901a:190; Woelkerling, 1984:50; Woelkerling, 1998:340; Woelkerling et al., 1998:529, 

figs. 240–241.

Lithophyllum diguetii (Hariot) Heydrich, 1901b:532; Foslie, 1909:26; Lemoine, 1911:120; Foslie, 1929:33, pl. 61: fig. 8; Dawson, 1944a:269, 

pl. 59: figs. 8, 11–16; 1960b:38, pl. 29: figs. 1–7; 1961b:416; Adey 

and Lebednik, 1967:45; Huerta-Múzquiz and Mendoza-González, 

1985:48; Dreckmann, 1991:34; Mateo-Cid et al., 1993:46; MendozaGonzález and Mateo-Cid, 1994:51; Steller and Foster, 1995:205, fig. 2; 

González-González et al., 1996:237; Foster et al., 1997:133; RiosmenaRodríguez and Paul-Chávez, 1997:71; Woelkerling, 1998:340; 

Riosmena-Rodríguez et al., 1999:403 [in part], fig. 6; RiosmenaRodríguez and Woelkerling, 2000:337; Pacheco-Ruíz and ZertucheGonzález, 2002:467; Schaeffer et al., 2002: fig. 2C.

Lithothamnion dentatum sensu Foslie, 1895b:5, pl. 1: fig. 15 [non Lithothamnion dentatum (Kützing) Areschoug, 1852:516; =Lithophyllum 

dentatum (Kützing) Foslie, 1900a:10].

Lithothamnion dentatum f. diguetii (Hariot) Foslie, 1901c:21.

Lithophyllum margaritae sensu Riosmena-Rodríguez et al., 1999:403, 411 

[in part: Lithophyllum diguetii and L. veleroae specimens only; non 

Lithophyllum margaritae (Hariot) Heydrich, 1901b:530].

Lithophyllum veleroae E. Y. Dawson, 1944a:270, pl. 55: fig. 5, pl. 56: figs. 

1–4; 1960b:52, pl. 47: figs. 1–4(type); 1961b:417; Huerta-Múzquiz and 

Mendoza-González, 1985:48; Ortega et al., 1987:74, pl. 4: fig. 22, pl. 

5: fig. 23; Anderson, 1991:32; Dreckmann, 1991:34; Mateo-Cid et al., 

1993:46; Mendoza-González and Mateo-Cid, 1994:51; Steller and Foster, 1995:205, fig. 2; González-González et al., 1996:239; Foster et al., 

1997:133; Riosmena-Rodríguez and Paul-Chávez, 1997:71; Woelkerling, 1998:328; Woelkerling et al., 1998:499, fig. 211; RiosmenaRodríguez et al., 1999:411, figs. 10–13; Riosmena-Rodríguez and 

Woelkerling, 2000:346.

Free-living crust, forming subspherical to irregularly shaped 

rhodoliths; of several thin foliose, simple to undulate or convoluted, anastomosing blade-likeextensions, up to 1–3 cm in length 

(seen from above), subcylindrical to compressed at their base and 

decreasing in thickness upward, 1.0–2.0 mm thick. Longitudinal 

sections of flat blade-like extensions internally with a distinct 

central core of filaments (medullary hypothallium) of more or 
NUMBER 96 • 105

less rectangular cells, 14–27 μm long, 9–11μm wide; perithallium thick, of rounded cells 12–17 μm long, 7.0–10 μm wide, 

with prominent pit connections linking some cells of adjacent 

filaments; filaments terminate at thallus surface in epithallial cells 

(wider than tall), about 3.5 μm tall, 9–12 μm wide.

Sporangial conceptacles scattered over flat, blade-like surfaces, embedded, nearly flush with surface, up to 100–125 μm 

tall, with a small central pore, chamber about 100 μm deep, up 

to 275 μm wide, with central columella; tetrasporangia (45–) 

60–70 μm long, (22–)35–45 μm in diameter. Carposporangial 

and spermatangial conceptacles not observed (description after 

Dawson, 1960b).

Habitat. Usually on sand plains; often component of 

extensive rhodolith beds; occasionally cast ashore; intertidal to 

subtidal, 2.0–13 m depths; dredged to 26 m depths.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda to Bahía de La Paz; Canal de San Lorenzo, Isla Espíritu Santo; Isla Partida; Laguna Agiabampo (Sonora and Sinaloa); Sinaloa to Jalisco.

Type Locality. La Paz, Baja California Sur, Gulf of 

California, Mexico.

Remarks. Dawson (1960b:44) observed Lithophyllum diguetii living in association with L. margaritae and L. 

lithophylloides (=L. pallescens) in the rhodolith beds in Canal de 

San Lorenzo, off Isla Espíritu Santo. 

Dawson (1960b:52) noted some specimens showed intermediate characters of L. diguetii, L. veleroae and L. lithophylloides and suggested there may be hybridization between them. 

These species were later considered to be within a broadly circumscribed “L. margaritae” (Riosmena-Rodríguez et al., 1999). 

Schaeffer et al. (2002, as L. margaritae) found two genetically 

distinct morphological forms. They questioned the validity of 

treating these as forms because of their genetic differences and 

the apparent limited genetic exchange between them. Although 

reproduction by vegetative fragmentation of these rhodoliths 

has been generally assumed, they found no genetic evidence of 

clones, suggesting there is little, if any, vegetative reproduction. 

Of the different morphologies they tested, their “foliose forms” 

(Schaeffer et al., 2002: fig. 2C) match L. diguetii. (See also Remarks under Lithophyllum margaritae and L. pallescens.)

Lithophyllum diguetii is recognized as a separate species on 

the basis of morphological and genetic differences.The type collection of another species, Lithophyllum veleroae E. Y. Dawson 

(1944a: pl. 56: figs. 1–4), a rhodolith described with channeled 

ridges, also seems morphologically close to L. diguetii. It is tentatively considered conspecific until molecular comparisons of 

FIGURE 46. Lithophyllum diguetii: A, C–G. Habit variability of rhodolith morphologies (EYD-591-40, AHFH, now UC). B. Isotype 

(L. Diguet-1894, UC).
106 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

their types and type locality material can assess their phylogenetic relationship and taxonomic status.

Lithophyllum hancockii E. Y. Dawson

FIGURE 47

Lithophyllum hancockii E. Y. Dawson, 1944a:268, pl. 55: fig. 1, pl. 62: fig. 

1; 1960b:40, pl. 31: fig. 1, pl. 24: fig. 2; 1961b:416; Salcedo-Martínez 

et al., 1988:83; Dreckmann, 1991:34; Anderson, 1991:31; EspinozaAvalos, 1993:333; León-Álvarez and González-González, 1993:461; 

González-González et al., 1996:238; Riosmena-Rodríguez and PaulChávez, 1997:71; Paul-Chávez and Riosmena-Rodríguez, 2000:147; 

Riosmena-Rodríguez and Woelkerling, 2000:340.

Crustose corallines forminga dense shrubby, irregularly 

branched cluster, up to 7 cm tall and up to 10 cm wide, attached 

to substratum by a thin, spreading crust. Branches subcylindrical 

and free of each other in upper portions, about 1.5 mm in diameter, with rounded or truncate apices; lower portion of branches 

wart-like or irregular in shape, often coalesced. Hypothallium 

in longitudinal section very thick, forming most of thallus, consisting of layers of elongate-rectangular cells, about 21 μm in 

length, 9–12 μm wide. Perithallium generally thin, or up to 250 

μm thick; of smaller rounded cells, 9–14 μm tall, 5–8 μm wide. 

Epithallium of cells, mostly 2.5 μm tall, 6–8 μm wide.

Sporangial conceptacles, immersed within thallus (with 

little to no surface bulge), 110–140 μm tall, 240–300 μm inside 

diameter, pore obscure; chamber floor with central columella 

surrounded by tetrasporangia, 50–60 μm tall, 25–30 μm in diameter; conceptacles become overgrown and deeply embedded 

within thallus with age. Gametangial conceptacles unknown 

(after Dawson, 1960b).

Habitat. On rocks and coral rubble; shallow subtidal.

Distribution. Gulf of California: Isla Espíritu 

Santo; Bahía de La Paz; Nayarit to Jalisco. Eastern Pacific: 

Guerrero.

Type Locality. Bahía San Gabriél, Isla Espíritu 

Santo, Baja California Sur, Gulf of California, Mexico.

Remarks. Lithophyllum hancockii is a little-known 

species in the Gulf of California and is included to call attention 

to the need for further study. It has also been reported in Pacific 

Mexico from Guerrero.

Lithophyllum imitans Foslie

FIGURE 48A,B

Lithophyllum imitans Foslie, 1909:13; 1929:35, pl. 54: figs. 10, 11; Dawson, 1945d:42; Mason, 1953:340, pl. 43; Dawson, 1960b:41, pl. 32: 

figs. 1–4, pl. 33: figs. 1–4, pl. 34: fig. 2, pl. 35: figs. 1, 2; Dawson et 

al., 1960a:68, pl. 20: fig 4; 1960b:16; Dawson, 1961a:416; Dawson et 

al., 1964:43, pl. 38: fig. A; Hollenberg and Abbott, 1966:62; Adey and 

Lebednik, 1967:18; Huerta-Múzquiz and Tirado-Lizárraga, 1970:128; 

Chávez-Barrear, 1972b:269; Huerta-Múzquiz and Garza-Barrientos, 

1975:8; Johansen, 1976a:393, fig. 338; Huerta-Múzquiz, 1978:335, 

340; Schnetter and Bula-Meyer, 1982:125, pl. 18, fig. A; PachecoRuíz and Aguilar-Rosas, 1984:72, 76; Stewart and Stewart, 1984:143; 

Huerta-Múzquiz and Mendoza-González, 1985:50; Mendoza-González 

and Mateo-Cid, 1986:423; Sánchez-Rodríguez et al., 1989:42; Stewart, 

1991:78; Ramírez and Santelices, 1991:211; Dreckmann, 1991:33; 

Mateo-Cid and Mendoza-González, 1991:20; Mendoza-González 

and Mateo-Cid, 1992:18; Mateo-Cid and Mendoza-González, 

1992:20; León-Álvarez and González-González, 1993:461; Woelkerling, 1993:121; Serviere-Zaragoza et al., 1993a:484; Mateo-Cid et al., 

1993:46; Stout and Dreckmann, 1993:14; Mateo-Cid and MendozaGonzález, 1994b:39; Mendoza-González et al., 1994:106; BulaMeyer, 1995:34; González-González et al., 1996:238, 401; RiosmenaRodríguez and Paul-Chávez, 1997:71; Rodríguez-Morales and 

Siqueiros-Beltrones, 1999:23; L. Aguilar-Rosas et al., 2000:131; MateoCid et al., 2000:64; Paul-Chávez and Riosmena-Rodríguez, 2000:147; 

Riosmena-Rodríguez and Woelkerling, 2000:340; Cruz-Ayala et al., 

2001:191; CONANP, 2002:139; Mateo-Cid et al., 2006:56; ServiereZaragoza et al., 2007:10; Fernández-García et al., 2011:62.

Crustose thalli up to 2 mm thick, pink; firmly adherent to 

subtratum, rocks, and shells; surfaces in some with low irregular 

surface undulations, others with lumpy surfaces of protuberances 

of variable size and shape. Protuberances simple, subcylindrical to 

broad based with lumpy rounded tops, mostly short, up to 5 mm 

(occasionally up to 10 mm) tall, and 2–3(–6) mm in diameter. 

Hypothallium not well developed, 35–220 μm thick (generally 

about 10%–12% of overall thallus thickness), of cells 13–27 μm 

long, 6–11(–14) μm wide. Perithallium forming major portion of 

crust, usually 400–1700 μm thick, of subquadrate cells, 9–11 μm 

in diameter, sometimes vertically elongated up to 18 μm.

FIGURE 47. Lithophyllum hancockii: Habit, crust beset with protuberances (holotype, EYD-619a-40, UC).
NUMBER 96 • 107

Sporangial conceptacles scattered, slightly protruding, up to 

400 μm outside diameter; chamber 180–330 μm inside diameter, 

51–117 μm high; tetrasporangia 40–60 μm long. Carposporangial conceptacles slightly prominent, about 200 μm inside diameter. Spermatangial conceptacles, chamber 120–167 μm inside 

diameter, 26–40 μm high, with flat floor. Old conceptacles becoming deeply buried in thallus.

Habitat. On rocks and shells and in tide pools; low 

intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabo Pulmo; Mazatlán, Sinaloa to Jalisco. Eastern Pacific: 

southern British Columbia to Todos Santos, Baja California 

Sur; Isla Guadalupe; Isla Clarión and Isla Socorro (Islas Revillagigedo); Colima to Oaxaca; El Salvador; Costa Rica; Panama; 

Isla de Gorgona, Colombia; Peru.

Type Locality. Pacific Beach (between La Jolla and 

Mission Beach, San Diego), San Diego County, southern California, USA.

Remarks. Lithophyllum imitans is one of the commonest crustose coralline species throughout the Gulf. In the 

field, L. imitans can be recognized by its surfaces: some with 

low, irregularly undulate, somewhat shiny surfaces, and others 

that have lumpy surfaces of narrow to broad protuberances with 

irregularly shaped rounded ends. All the other species of Lithophyllum in the Gulf of California have more densely crowded 

surfaces, with more elaborate protuberances.

Lithophyllum margaritae (Hariot) Heydrich

FIGURE 48C

Lithothamnion margaritae Hariot, 1895:167; Foslie, 1900e:20; Woelkerling, 

1998:354; Woelkerling et al., 1998:569, figs. 281–283; R. AguilarRosas et al., 2009:7, fig. 2f.

Lithophyllum margaritae (Hariot) Heydrich, 1901b:530; Lemoine, 

1911:174, fig. 100, pl. 2: fig. 2; Dawson, 1944a:266; 1960b:44, pl. 36: 

fig. 2; 1961b:416; Huerta-Múzquiz and Mendoza-González, 1985:48; 

Dreckmann, 1991:34; Mendoza-González and Mateo-Cid, 1994:51; 

FIGURE 48. Lithophyllum imitans: A. Close-up of numerous conceptacles, each with a single pore (JN & HWJ 73-7-11a, US Alg. Coll.). B. Surface view of crust (JN-4025, US Alg. Coll.). C. Lithophyllum margaritae: habit variations of four specimens (EYD-6942, AHFH, now UC).
108 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

González-González et al., 1996:238; Riosmena-Rodríguez and PaulChávez, 1997:71; Riosmena-Rodríguez et al., 1999:411 [in part; excluding L. diguetii and L. pallescens], figs. 2–5; Foster, 2001:660, 

fig. 1A; CONANP, 2002:139; Pacheco-Ruíz and Zertuche-González, 

2002:467; Pacheco-Ruíz et al., 2008:208; Riosmena-Rodríguez et al., 

2010:58; Ávila and Riosmena-Rodríguez, 2011:368, fig. 2.

Pseudolithophyllum margaritae (Hariot) Me. Lemoine, 1913:46. 

Lithothamnion elegans Foslie, 1895b:6; Heydrich, 1897b:64; 1897c:415; 

Woelkerling, 1984:52; Woelkerling, 1993:83; Riosmena-Rodríguez et 

al., 1999:411, fig. 8 (upper), Riosmena-Rodríguez and Woelkerling, 

2000:338.

Lithothamnion elegans f. angulata Foslie, 1895b:6, pl. 1: fig. 9, nom. superfl.; 

Woelkerling, 1993:27. 

Lithothamnion elegans f. complanata Foslie, 1895b:5, pl. 1: fig. 10; Heydrich, 1897b:64; 1897c:415; Adey and Lebednik, 1967:19; Adey, 

1970:19; Woelkerling, 1993:83.

Lithophyllum elegans (Foslie) Foslie, 1900e:20; 1909:27; 1929:34: pl. 63, 

figs. 1, 2; Setchell and Mason, 1943b:95; Adey and Lebednik, 1967:44; 

Riosmena-Rodríguez et al., 1999:411, fig. 8 (lower). 

Lithophyllum elegans f. angulata Foslie, 1900e:20, nom. superfl. [see Woelkerling, 1993:83]. 

Rhodoliths of compressed to flattened, variously shaped, 

angular plate-like portions, with irregular, subcylindrical to compressed, often elongated, branch-like extensions narrowing to 

pointed or sometimes truncate apices. Structurally monomerous, 

with a central core of filaments (=medullary hypothallium sensu 

Dawson, 1960b) of cells about 20 μm by 10 μm; filaments outwardly curve upward (=perithallium sensu Dawson, 1960b), with 

cells (about 15 μm by 8 μm) of adjacent filaments linked laterally 

by secondary pit connections; each filament terminating with a 

single (rarely 2) small flattened epithallial cell(s) at thallus surface.

Sporangial conceptacles within surfaces of branches, mostly 

flush or bulging very little on surface; chamber 140–200 μm 

inside diameter, somewhat dumbbell-shaped in vertical section 

with a central columella; chamber roof with a single pore. Tetrasporangia up to 50 μm long and about 25 μm in diameter. 

Gametangial conceptacles not known. 

Habitat. Free-living rhodoliths that may cover considerable areas, often growing with other rhodolith species; intertidal to subtidal.

Distribution. Gulf of California: Canal de San Lorenzo, off Isla San Espíritu Santo to Isla San Juan Nepomuceno; 

Bahía de La Paz. 

Type Locality. Subtidal bank off Isla San Juan 

Nepomuceno (“Nepomezeino”), off the coast about 4 km from 

Pichilinque (between Punta Colorado and Punta Base) north of 

La Paz, Baja California Sur, Gulf of California, Mexico.

Remarks. Dawson (1960b:44) noted problems identifying some forms of Gulf rhodoliths with apparent intergrading 

morphologies that made it difficult to distinguish species. He suggested Lithophyllum margaritae, L. diguetii, L. lithophylloides,

and L. veleroae possibly may be forms of a single polymorphic 

species but then concluded that those with distinct morphologies 

should be kept as separate species. Subsequent morphological 

studies of Riosmena-Rodríguez et al. (1999, as L. margaritae) 

considered these species and a few others to represent a single, 

broadly defined, highly variable species.

Schaeffer et al. (2002), however, found genetic differences 

and apparently little evidence of genetic mixing that supported 

separation of two morphological forms of L. margaritae: “fruticose forms, fig. 2A” that are closest to L. pallescens, and “foliose 

forms, fig. 2C” that agree with L. diguetii. They also had three 

“not-tested, intermediate forms, fig. 2B (upper left & two middle)” as “L. margaritae.” Of the several species considered conspecific by Riosmena-Rodríguez et al. (1999), L. margaritae, L. 

diguetii, and L. pallescens are recognized herein. Although these 

could be considered taxonomic varieties or subspecies, rather than 

propose new combinations, for now each is treated as a species 

until further molecular testing can elucidate their relationships 

and taxonomic status. (see also Remarks under L. diguetii and L. 

pallescens.)

Lithophyllum pallescens (Foslie) Foslie

FIGURE 49A–E

Lithothamnion pallescens Foslie, 1895b:4, pl. 1: figs. 11–13; 1897:13; Heydrich, 1897b:60; 1897c:413; Foslie, 1901a:20; 1909:36; Lemoine, 

1911:156, figs. 87–91; Foslie, 1929:37, pl. 64: figs. 15–17; Adey and 

Lebednik, 1967:42; Woelkerling, 1984:85; 1993:167; 1998:357; 

Woelkerling et al., 1998:577, figs. 289, 290; Riosmena-Rodríguez et 

al., 1999:411, fig. 9.

Lithophyllum pallescens (Foslie) Foslie, 1900a:20; Adey, 1970:5; Adey et 

al., 1982:40, figs. 23, 27; Schnetter and Bula-Meyer, 1982:126, pl. 15: 

figs. K, L, pl. 17: figs. D, E; Huerta-Múzquiz and Mendoza-González, 

1985:48; Mendoza-González and Mateo-Cid, 1986:423; Dreckmann, 

1991:34; Mendoza-González and Mateo-Cid, 1994:51; Steller and Foster, 1995:205, fig. 2; González-González et al., 1996:238; Foster et al., 

1997:133; Riosmena-Rodríguez and Paul-Chávez, 1997:71; L. AguilarRosas et al., 2000:131; Mateo-Cid et al., 2000:65; Schaeffer et al., 

2002: fig. 2A; Fernández-García et al., 2011:62. 

Lithophyllum pallescens (Foslie) Heydrich, 1901b:531; Dawson, 1944a:266, 

pl. 55: fig. 4; 1960a:45, pl. 31: fig. 2, pl. 38, pl. 39: figs. 1, 2; 1961b:416; 

1966a:19; Schwab, 1969:189, figs. 1–14; Mendoza-González and 

Mateo-Cid, 1986:423; Espinoza-Avalos, 1993:334; Mateo-Cid et al., 

1993:46; Bula-Meyer, 1995:34; Woelkerling et al., 1998:577, figs. 289, 

290; Riosmena-Rodríguez and Woelkerling, 2000:343; Cruz-Ayala et 

al., 2001:191. 

Goniolithon pallescens Foslie, 1898:9.

Lithophyllum lithophylloides Heydrich, 1901b:531; Dawson, 1944a:269, 

pl. 55: fig. 3, pl. 58: figs. 2, 3(type), 7, pl. 59: figs. 9, 10, pl. 61: fig. 

1; 1960b:43, pl. 16: fig. 2, pl. 29: figs. 8, 9; 1961b:416; Adey and 

Lebednik, 1967:48; Huerta-Múzquiz and Mendoza-González, 

1985:48; Dreckmann, 1991:34; León-Álvarez and González-González, 

1993:461; León-Tejera and González-González, 1993:497; Woelkerling, 1993:138, 172; Serviere-Zaragoza et al., 1993a:484; MendozaGonzález and Mateo-Cid, 1994:51; González-González et al., 

1996:238, 401; León-Tejera et al., 1996:164; Riosmena-Rodríguez 

and Paul-Chávez, 1997:71; Woelkerling, 1998:354; Woelkerling et al., 

1998:476, figs.188–189; Riosmena-Rodríguez et al., 1999:411, fig. 7; 

Riosmena-Rodríguez and Woelkerling, 2000:327; Pacheco-Ruíz and 

Zertuche-González, 2002:467.
NUMBER 96 • 109

Lithothamnion lithophylloides (Heydrich) Foslie, 1907:11.

Crusts spreading on hard substratum, rocks, shells, or coral 

fragments; surfaces crowded with short, subcylindrical knob-like 

protuberances; or free-living subspherical-shaped, knobby rhodoliths, up to 5 cm in diameter. Protuberances simple to little 

branched, 2–4 mm in diameter, anastomosing in lower portions, 

with rounded or knob-shaped to club-shaped tops; in longitudinal sections, with a thick central core of filaments (medullary 

hypothallium) of elongated cells, 14–20 μm long, 9–11μm wide; 

perithallium layers of filaments of ovate to subspherical cells 

about 7.0–10 μm in diameter; some cells of adjacent perithallial 

filaments laterally linked by pit connections; epithallium of cells 

(wider than tall), about 2.4–3.5 μm tall, 7–9 μm wide.

Reproductive conceptacles scattered over surfaces of protuberances, embedded, nearly flush with surface or very low dome 

shaped (not prominent), with small central pore. Sporangial 

conceptacle chambers about 100 μm deep, 225–300 μm inside 

diameter; tetrasporangia 50–60 μm tall, 35–45 μm in diameter. 

Carposporangial conceptacles about 80–100 μm tall, 200–280 

μm inside diameter, with nearly flat floor; a central fusion cell 

with peripheral gonimoblast filaments bearing terminal carposporangia. Spermatangial conceptacles chambers about 30–80 

μm tall, 150–175 μm inside diameter, with simple spermatangial 

filaments along the floor (description after Dawson, 1960b).

Habitat. Crusts on hard substratum in tide pools, 

partially attached to small pieces of rock, shells, or coral fragments, or free-living rhodoliths that may cover considerable areas; 

intertidal to shallow subtidal, 1–26 m depths (Dawson, 1960b).

Distribution. Gulf of California: Puerto Peñasco 

to Isla Pelícanos, Bahía Kino; El Machorro, San Felipe to Puerto 

Escondido; Isla Mejía and NW side of Puerto Refugio, Isla Ángel 

de la Guarda; south of Santa Rosalía to laguna San Gabriel and 

Canal de San Lorenzo, Isla Espíritu Santo; Isla Carmén; Bahía de 

La Paz to Cabo Pulmo; Laguna Agiabampo, Sinaloa to Jalisco; 

FIGURE 49. Lithophyllum pallescens: A, B, D. Variability of rhodolith morphologies (A, EYD-278-40; B, EYD-250-40; D, EYD-572-50, all 

AHFH, now UC). C, E. Close-up of protuberances (C, JN-3586; E, JN-3503, both US Alg. Coll.).
110 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Isla María Magdalena (Islas Marías; Islas Tres Marías). Eastern 

Pacific: Isla Clarión and Isla Socorro (Islas Revillagigedo); Jalisco 

to Oaxaca; Isla Brincanco and Isla Contreras, Panama; Isla de 

Gorgona, Colombia. Central Pacific: Hawaiian Islands.

Type Locality. Subtidal bank of west shore, off Isla 

Espíritu Santo, Baja California Sur, Gulf of California, Mexico 

(locale information from map of M. Diguet and transcribed by 

Madame Marie Lemoine (PC), Paris; Dawson, 1944a:266).

Remarks. In the field, some forms of Lithophyllum

pallescens may be confused with L. proboscideum. However, L.

pallescens lack the broad, flat-topped protuberances of L. proboscideum. Subsequent morphological studies of RiosmenaRodríguez et al. (1999, as Lithophyllum margaritae) considered 

these species and a few others to represent a single, broadly defined, highly variable species.

Schaeffer et al. (2002, as L. margaritae) found genetic differences and little apparent evidence of genetic mixing that supported separation of two morphological forms. Their “fruticose 

forms” (Schaeffer et al., 2002, fig. 2A) are closest to L. pallescens. (See also Remarks under L. margaritae and L. diguetii.) 

The type collection of L. lithophylloides appears to be close to 

L. pallescens, and L. lithophylloides is tentatively treated as a 

synonym until molecular analyses can be done on type material.

Lithophyllum proboscideum (Foslie) Foslie

FIGURE 50

Lithothamnion proboscideum Foslie, 1897:14; Heydrich, 1897c:414; 

Woelkerling, 1993:176.

Lithophyllum proboscideum (Foslie) Foslie, 1900a:18; 1929:37, pl. 63: figs. 

3, 4; Smith, 1944:227; Dawson, 1945d:42; Mason, 1953:342, pl. 46a, 

b; Dawson, 1960b:47, pl. 40: figs. 1–5, pl. 41: figs. 1, 2, pl. 42: figs. 

1, 2; 1961b:416; 1966a:19; Adey and Lebednik, 1967:44; Johansen, 

1976a:393, fig. 340; Adey, 1970:5; Littler and Littler, 1981:153; Lewber et al., 1983:164; Pacheco-Ruíz and Aguilar-Rosas, 1984:72, 76; 

Stewart and Stewart, 1984:143; Mendoza-González and Mateo-Cid, 

1986:423; Steneck and Paine, 1986:231; Ortega et al., 1987:73, pl. 5: 

fig. 24, pl. 6: fig. 25; R. Aguilar-Rosas et al., 1990:124; Dreckmann, 

1991:33; Stewart, 1991:78; León-Álvarez and González-González, 

1993:461; Serviere-Zaragoza et al., 1993a:484; Mateo-Cid et al., 

1993:46; Mendoza-González and Mateo-Cid, 1994:51; R. AguilarRosas and Aguilar-Rosas, 1994:520; González-González et al., 

1996:239, 401; L. Aguilar-Rosas et al., 2000:131; Riosmena-Rodríguez 

and Woelkerling, 2000:344; Cruz-Ayala et al., 2001:191; Mateo-Cid et 

al., 2006:56.

Crusts on hard substratum; spreading, covering up to 17 

cm or more, and to 2 mm or more thick; crowded with stout, 

subcylindrical flat-topped protuberances. Protuberances simple 

FIGURE 50. Lithophyllum proboscideum: A. Portion of crust showing broad-topped protuberances (JN-3825, US Alg. Coll.). B. Closeup of protuberances with conceptacles (JN-3471, US Alg. Coll.).
NUMBER 96 • 111

(undivided) to divided, frequently anastomosed; up to 3 cm high 

and to 3 mm in diameter at base; broadening upward, usually 

4–5 mm (occasionally more) in diameter at enlarged and typically flat-topped ends, sometimes with a central apical depression. Hypothallium well developed, of elongate cells 14–36 μm 

long, 7–12 μm wide. Perithallium of several layers; perithallial 

filaments similar in both crustose portion and protuberances, of 

squarish cells, 6–9 μm in diameter, or slightly vertically elongated, 9–11 μm long, (6–)7–9 μm wide; perithallial cells of protuberances, 8–16 long, 6–8 μm in diameter. Epithallium of 3–4 

layers of small cells (wider than tall), 2–4 μm tall, 6–8 μm wide 

(after Mason, 1953; Dawson, 1960b).

Sporangial conceptacles scattered over the lower surfaces of 

the protuberances, immersed, 190–300 μm in diameter, 95–125 

μm high; tetrasporangia 50–60 μm high, 30–35 μm in diameter. 

Gametangial thalli not reported in the northern Gulf.

Habitat. On rocks and in tide pools; intertidal to 

shallow subtidal.

Distribution. Gulf of California: Playa Arenosa 

(Norse Beach), Puerto Peñasco to Bahía Concepción; Bahía de 

La Paz; Bocochibampo (near Guaymas); Laguna Agiabampo; 

Mazatlán, Sinaloa to Jalisco. Eastern Pacific: southern British 

Columbia to Baja California; Islas Todos Santos and Isla Guadalupe, Baja California; Colima to Oaxaca.

Type Locality. Dredged off Monterey, Monterey 

County, central California, USA.

Remarks. Apparently a common crustose coralline 

in the Gulf, Lithophyllum proboscideum is conspicuous and 

recognized by its prominent and characteristic broad, usually 

flat-topped protuberances. The shape and size of these protuberances may vary considerably, sometimes even in a single 

specimen.

Pseudolithophyllum Me. Lemoine

Pseudolithophyllum Me. Lemoine, 1913:45, fig. 13A; Adey, 1966a:480; 

Cabioch, 1972:144, fig. 1A, figs. 1, 2–6 (generitype); Mendoza and 

Cabioch, 1985:144 [non Pseudolithophyllum sensu Adey, 1970:12].

Pseudolithophyllum Me. Lemoine, 1912:783, nom. illeg.

Crustose corallines are with or without protuberances. 

Crustose portion varies in thickness from very thin, 50–200 μm, 

to 1–2 mm. The hypothallium is a single layer of cells (but at 

least one, Pseudolithophyllum neofarlowii, may have up to three 

weakly developed layers; Dawson, 1960b) that produces ascending rows of perithallial filaments. The perithallium is well developed, comprising almost the entire thickness of the thallus, 

and is weakly to strongly layered, with the cells of the perithallial filaments not laterally aligned in horizontal rows. Secondary 

perithallial outgrowths are also present. Subepithallial initials 

(meristematic cells) are intercalary and directly below the epithallium. Epithallial cells are present but may degenerate or be 

lacking in portions of the thallus. Lateral cell fusions are present 

between cells of adjacent filaments. Trichocytes and secondary 

pit connections are absent. 

Sporangial conceptacles may be slightly sunken, flush with 

the surface, or in raised dome structures, and have a roof with 

a single pore.

Remarks. There have been questions about the taxonomy and nomenclature of Pseudolithophyllum Me. Lemoine 

(1913). The implicit generitype is Lithophyllum fuegianum Heydrich (1901b), which Foslie (1901c) considered conspecific with 

L. discoideum Foslie (1900f). Lemoine (1913:46) followed Foslie’s (1901c) synonomy in making the combination P. discoideum

(Foslie) Me. Lemoine. Later, Lemoine (1978), using cytological 

characters, recognized that L. fuegianum Heydrich and L. discoideum Foslie were two different species, noting L. fuegianum

Heydrich (1901b) was the type species for Pseudolithophyllum.

Mendoza and Cabioch (1985) also found Lithophyllum discoideum to comprise two species, and treated L. discoideum Foslie as Hydrolithon discoideum (Foslie) M. L. Mendoza et Cabioch 

(1985; later considered Spongites discoideus (Foslie) Penrose et 

Woelkerling, 1988, as ‘discoidea’). On the basis of their study of 

the type species, L. fuegianum Heydrich (1901b), Mendoza and 

Cabioch (1985) redescribed the genus and made the combination Pseudolithophyllum fuegianum (Heydrich) M. L. Mendoza 

et Cabioch. Silva (1986) and Silva (in Silva et al., 1996a) evaluated the confused nomenclature history of Pseudolithophyllum

and concluded the generic name in the sense of Lemoine can be 

used without being conserved and is typified by P. fuegianum.

The generic placement of some species within the Lithophyllum–Pseudolithophyllum complex is uncertain because the 

distinctiveness of the genera is in question. Penrose and Woelkerling (1988) treated the generitype, L. fuegianum Heydrich, as 

a Lithophyllum, which would make Pseudolithophyllum congeneric—a conclusion supported by Woelkerling (1988), Chamberlain and Irvine (1994a), and Athanasiadis (1999). Herein 

Pseudolithophyllum is tentatively recognized on the basis of its 

characters (see also Guiry and Guiry, 2012), until genetic analyses can clarify its taxonomic status.

The generic status of another, “Pseudolithophyllum sensu 

Adey,” is still problematic. Adey (1970) redefined Pseudolithophyllum based on Foslie’s collection of Lithothamnion orbiculatum Foslie (1895a; =Lithophyllum orbiculatum (Foslie) Foslie, 

1900e; =Pseudolithophyllum orbiculatum (Foslie) Me. Lemoine, 

1929b). Characters used by Adey (1970) did not agree with the 

genus as defined by Hamel and Lemoine (1953), Adey (1966a), 

or Cabioch (1972). If the generic concept of Pseudolithophyllum

sensu Adey should be accepted, it is seemingly without a type 

and will apparently need a new generic name.

One species of Pseudolithophyllum has been reported in the 

northern Gulf of California.

Pseudolithophyllum neofarlowii (Setchell et L. R. Mason) 

W. H. Adey

Lithophyllum neofarlowii Setchell et L. R. Mason, 1943b:95; Smith, 

1944:228; Mason, 1953:341, pl. 45a[isotype]–c; Dawson, 1960b:45, 

pl. 37: figs. 1–2, pl. 43: fig. 2; 1961b:416; Adey and Lebednik, 1967:17; 

González-González et al., 1996:238; Yoshida, 1998:576.
112 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Pseudolithophyllum neofarlowii (Setchell et L. R. Mason) W. H. Adey, 

1970:13; Johansen, 1976a:397, fig. 343; Silva, 1979:319; Steneck and 

Paine, 1986:227, figs. 10–12; Scagel et al., 1989:246; Stewart, 1991:79; 

González-González et al., 1996:261.

Lithophyllum farlowii Foslie, 1901a:12, nom. illeg.; 1929: pl. 54: figs. 5, 6; 

Woelkerling, 1993:90; 1998:310, fig. 173; Woelkerling et al., 1998:401, 

fig. 173 [non Lithophyllum farlowii Heydrich, 1901b:532; Woelkerling, 

1998:311; Woelkerling et al., 1998:462, figs. 174–175; which is now 

Lithophyllum decussatum (J. Ellis et Solander) Philippi, 1837:389; basionym: Millepora decussata J. Ellis et Solander, 1786:131, pl. 23: fig. 9].

Crustose coralline, initially discoid, later becoming irregular in outline, spreading up to 10 cm wide; 300–500(–1000) μm 

thick, with rough surface of low hemispherical to subspherical 

protuberances, mostly 1–2 mm in diameter, usually densely congested, sometimes growing together. Hypothallium either apparently lacking or weakly developed, of 1–3 cell layers; cells mostly 

7–10 μm long by 3–6 μm wide. Perithallium of several ascending 

layers; cells squarish but can be slightly wider than tall, 5–15 

μm tall by 6–12 μm wide. Epithallium usually a single layer, occasionally of 2 layers; upper surface of rounded and relatively 

thick-walled cells, 2–4 μm tall, 4–8 μm wide. Cell fusions abundant; trichocytes absent. 

Reproductive conceptacles on crust surface and at base of 

protuberances up to 250 μm in outside diameter, with a single 

pore opening. Sporangial conceptacles hemispherical, 180–225 

μm inside diameter, 50–100 μm deep; tetrasporangia 90–100 μm 

tall, 50–60 μm in diameter. Carposporangial conceptacles 190–

215 μm outside diameter (80–100 μm inside diameter; about 65 

μm deep). Spermatangial conceptacles 100–200 μm outside diameter (90–110 μm inside diameter; 40–50 μm deep). 

Habitat. On rocks and in tide pools; mid to low 

intertidal.

Distribution. Gulf of California: San Felipe to 

Punta Palmilla. Eastern Pacific: southern Alaska to Bahía Asunción, Baja California. Western Pacific: Japan. 

Type Locality. Monterey, Monterey County, California, USA. 

Titanoderma Nägeli

Titanoderma Nägeli in Nägeli and Cramer, 1858:532; Chamberlain, 

1991:13, 22, figs. 1–48, 50, 51; Irvine and Chamberlain, 1994:89.

Dermatolithon Foslie, 1898:11.

Crustose thalli that are irregular in outline (surface view), 

mostly with smooth to irregular surfaces, and some may have 

protuberances; attached loosely or tightly adherent on other 

algae, sometimes surrounding host branches, or some attached 

to hard substratum such as rocks. Crustose portions are dorsiventrally organized and dimerous or dimerous and monomerous; protuberances, if present, are radially organized and 

monomerous. In dimerous crusts, filaments of the first order 

(hypothallium) are composed of 1 layer of palisade cells (elongated cells) oriented obliquely to vertically to the substratum or 

host. Second-order filaments (perithallium) grow at right angles 

from the first-order filaments. In some species these filaments are 

unicellular (i.e., only an epithallial cell), while in others the filaments are multicellular with a subepithallial initial that issues 

epithallial cells outward toward the crust surface, and additional 

vegetative cells inward. Terminal epithallial cells are rounded or 

flattened. Secondary pit connections are present between some 

cells of adjoining filaments. Cell fusions are absent or rare. 

Trichocytes are absent in most members.

Sporangial conceptacles have a single pore, tetrasporangia 

and bisporangia are without apical plugs. The conceptacles may 

be with or without a central columella. Tetrasporangia and bisporangia develop around the chamber periphery if a columella 

is present; if absent, they are scattered across the conceptacle 

floor. Gametangial thalli are poorly known.

Remarks. Although some recognized Titanoderma as 

a distinct genus (e.g., Woelkerling, 1988; Chamberlain, 1991; Irvine and Chamberlain, 1994), others have questioned its generic 

status (e.g., Woelkerling et al., 1985; Bittner et al., 2011) or have 

considered it to be congeneric with Lithophyllum (e.g., Campbell 

and Woelkerling, 1990, Woelkerling and Campbell, 1992). Titanoderma is morphologically close to Lithophyllum in that both 

genera lack haustoria (specialized cells that are presumed to absorb nutrients from host) and are dorsiventrally (distinct dorsal 

and ventral sides) or radially organized. Perithallial cells of Titanoderma are frequently laterally connected to neighboring cells by 

secondary pit connections, a character also seen in Lithophyllum. 

Unlike Lithophyllum, the cells of primigenous filaments of Titanoderma are palisade (vertically elongated), forming a unistratose 

ventral cell layer; but use of this character to separate these genera 

has been questioned by Woelkerling et al. (1985, 2012).

Campbell and Woelkerling (1990), Woelkerling and Campbell (1992), and Woelkerling (1996a) considered the type of the 

genus, Titanoderma pustulatum (J. V. Lamouroux) Nägeli (in 

Nägeli and Cramer, 1858; basionym: Melobesia pustulata J. V. 

Lamouroux, 1816), to be conspecific with Lithophyllum pustulatum (J. V. Lamouroux) Foslie (1904). Thus the genus Titanoderma would be congeneric with Lithophyllum. Others have kept 

the genera separate (e.g., Adey, 1970; Irvine and Johansen, 1994; 

Silva et al., 1996a), and on the basis of the molecular analyses of 

T. pustulata (generitype), Bailey (1999) concluded Titanoderma

was genetically distinct from Lithophyllum but that the two genera were difficult to separate solely on morphology. Bittner et al. 

(2011) noted that while limited molecular data supported their 

separation, anatomical characters alone could not distinguish 

Titanoderma and Lithophyllym, and they similarly concluded 

that additional morphological, anatomical, and molecular studies 

were needed to better circumscribe these two genera.

Some species of Titanoderma have been referred to Dermatolithon Foslie (1898). However, the generitype, D. pustulatum

(J. V. Lamouroux) Foslie (1898; basionym: Melobesia pustulata

J. V. Lamouroux, 1816), is currently considered to be either 

Lithophyllum pustulatum (J. V. Lamouroux) Foslie (1904; see 

Campbell and Woelkerling, 1990) or Titanoderma pustulatum 

(see Chamberlain, 1991). For now, Titanoderma is herein recognized until critical studies, including molecular analyses, can be 

carried out on the generitypes and type locality material.
NUMBER 96 • 113

The generic placement of Dermatolithon veleroae E. Y. 

Dawson (1944a: 274), described from Bahía Agua Verde, Baja 

California Sur, also needs to be reevaluated. Other southern Gulf 

reports of D. veleroae are in Dawson (1960b, 1961b), EspinozaAvalos (1993), Riosmena-Rodríguez and Woelkerling (2000), 

and Dreckmann (1991, as Lithophyllum veleroae (E. Y. Dawson) 

Woelkerling ex Dreckmann, comb. invalid.; non Lithophyllum 

veleroae E. Y. Dawson, 1944a: 270). 

Three species of Titanoderma, including one with two varieties, are known to occur in the northern Gulf of California.

KEY TO THE SPECIES OF TITANODERMA IN THE NORTHERN GULF OF CALIFORNIA

1a. Crusts in transsections of 3 different types of cell layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Crusts in cross sections of 2 different types of cell layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2a. Crusts thin, less than 120 μm thick; sporangial conceptacles 300–350(–500) μm in outside diameter . . . . . T. canescens

2b. Crusts much thicker, up to 1(–2) mm thick; sporangial conceptacles 200–350 μm in diameter . . . . . . . . . . . . . T. dispar

3a. Sporangial conceptacle roof 3 cells thick throughout, cells in each layer of more or less consistent size and regular arrangement; top (epithallial) layer and bottom layer of small cells, middle layer of vertically elongated cells . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. pustulatum var. pustulatum

3b. Sporangial conceptacle roof 3–5 (or more) cells near pore; cells somewhat variable in size and irregular arrangement . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. pustulatum var. confine

Titanoderma canescens (Foslie) Woelkerling, Y. M. Chamberlain 

et P. C. Silva

Melobesia canescens Foslie, 1900d:6 [as “Melobesia (Heteroderma) canescens”]; Adey and Lebednik, 1967:37; Woelkerling, 1993:47.

Titanoderma canescens (Foslie) Woelkerling, Y. M. Chamberlain et P. C. 

Silva, 1985:333; Yoshida, 1998:333.

Lithophyllum canescens (Foslie) Foslie, 1905b:8; Foslie, 1929:32, pl. 72: 

fig. 3 [type]; Dreckmann, 1991:34; Bernecker, 2009:CD-Rom p. 59; 

Fernández-García et al., 2011:62. 

Dermatolithon canescens (Foslie) Foslie, 1909d:58; Dawson, 1955:274; 

1960b:33, pl. 21: fig. 3; Masaki and Tokida, 1960:38, pl. 1: figs. 2–3, 

pl. 2: figs. 4–7, pl. 5; Masaki, 1968:49. 

Tenarea canescens (Foslie) W. H. Adey, 1970:7; Stewart and Stewart, 

1984:143; Mateo-Cid and Mendoza-González, 1992:20; MendozaGonzález and Mateo-Cid, 1992:18; Mendoza-González and MateoCid, 1994:51; Mendoza-González et al., 1994:107; RiosmenaRodríguez and Woelkerling, 2000:335.

Crusts pink, epiphytic, orbicular on flat surfaces of algal 

host, up to 2 cm wide, or encircling host branches; mostly less 

than 120 μm thick; hypothallium of palisade cells 25–60(–100) 

μm tall; perithallium little developed; epithallium of small triangular cells (in cross section).

Tetrasporangial conceptacles protruding, more or less hemispherical, 300–350(–500) μm in outside diameter. Carposporangial and spermatangial conceptacles not observed.

Habitat. Epiphytic on Dictyota and Padina and 

probably on various other red and brown algae; intertidal to 

shallow subtidal.

Distribution. Gulf of California: Punta Colorado (Sonora); Isla Turner off SE end of Isla Tiburón; Mazatlán, Sinaloa. Eastern Pacific: Isla Guadalupe; El Salvador; Costa 

Rica. Western Pacific: Japan.

Type Locality. On Padina arborescens, [Manazuru] Marine Laboratory, Sagami Province (now Kanagawa Prefecture), Honshū, Japan.

Remarks. Dawson (1960b, as “Dermatolithon 

canescens”) noted Titanoderma canescens seems to be more 

characteristic of warmer waters. Johansen (1976a, as Tenarea 

canescens; see also Stewart, 1991) said the records of Dawson 

(1960b: Santa Cruz Island and Cardiff, San Diego) required 

further study to verify the presence of T. canescens in southern 

California.

Titanoderma dispar (Foslie) Woelkerling, Y. M. Chamberlain et 

P. C. Silva

FIGURE 51

Lithophyllum tumidulum Foslie f. dispar Foslie, 1907:29; Nichols, 

1909:357, pl. 10: fig. 6, pl. 11: figs. 11, 13, 14, pl. 13: figs. 26, 27; 

Mason, 1953:344 (lectotype).

Titanoderma dispar (Foslie) Woelkerling, Y. M. Chamberlain et P. C. Silva, 

1985:333; Scagel et al., 1989:262; Mateo-Cid and Mendoza-González, 

1994b:40; R. Aguilar-Rosas and Aguilar-Rosas, 1994:520; Mateo-Cid 

and Mendoza-González, 1997:57, pl. 1: fig. 5; Yoshida, 1998:619; 

L. Aguilar-Rosas et al., 2000:131; Riosmena-Rodríguez and Woelkerling, 2000:338; Y.-P. Lee, 2008:211, figs. A–E.

Lithophyllum dispar (Foslie) Foslie, 1909:50; 1929:33, pl. 72: fig. 14 (type); 

Adey and Lebednik, 1967:39; Woelkerling, 1993:77.

Dermatolithon dispar (Foslie) Foslie, 1909:58; Mason, 1953:343; Dawson, 

1960b:34, pl. 23: fig. 1, pl. 25: figs. 4, 5; Dawson et al., 1960a:16; Masaki and Tokida, 1960:37, pl. 1: fig. 1, pl. 2: figs. 1–3, pls. 3, 4; Dawson, 

1961b:415; Masaki, 1968:52; Mendoza-González and Mateo-Cid, 

1985:28; González-González et al., 1996:198.

Fosliella dispar (Foslie) G. M. Smith, 1944:225, pl. 50: fig. 6.

Tenarea dispar (Foslie) W. H. Adey, 1970:7; Johansen, 1976a:395, fig. 

342; Stewart, 1991:80; Mateo-Cid and Mendoza-González, 1992:20; 

Mendoza-González and Mateo-Cid, 1992:19; Mateo-Cid et al., 

1993:47; Serviere-Zaragoza et al., 1993a:484; Mendoza-González et 

al., 1994:107; González-González et al., 1996:272.

Thalli epiphytic, forming orbicular to irregularly shaped 

crusts, up to 1.0 cm in diameter, mostly less than 1 mm (occasionally up to 2 mm) thick; often partly to completely encircling 

host. Polystromatic: hypothallial filaments of obliquely elongated cells, 15–100 μm long by 2–11 μm diameter; perithallium 

of 2–7 cell layers, erect filaments of elongated cells, 12–120 μm 
114 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

long by 3–11 μm diameter; epithallium of rectangular cells, periclinally flattened, 2–10 μm wide by 2–3 μm tall.

Tetrasporangial and bisporangial conceptacles slightly convex, 120–210 μm tall and up to 375 μm outside diameter, with 

central columella; tetrasporangia 100–150 μm long by 50–70 

μm diameter. Carposporangial conceptacles slightly convex to 

slightly protruding, 225–260 μm inside diameter and 300–350 

μm outside diameter (after Dawson, 1960b). Spermatangial conceptacles 35–45 μm tall and 90–120 μm outside diameter (after 

Mason, 1953, as Dermatolithon dispar).

Habitat. Epiphytic on various algae, including 

Gelidium, Gracilaria, Laurencia, and Digenea; mid intertidal to 

shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco; 

Bahía Concepción to Guaymas; Cabeza Ballena; Mazatlán; 

Sinaloa to Nayarit. Eastern Pacific: Alaska to Todos Santos, Baja 

California Sur; Oaxaca. Western Pacific: Japan; Korea.

Type Locality. In drift, epiphytic on Ahnfeltia gigartinoides (=Ahnfeltiopsis gigartinoides (J. Agardh) P. C. Silva 

et DeCew); Whidbey (Whidby) Island, Island County, Puget 

Sound, Washington, USA.

Remarks. Relatively rare in the Gulf of California, 

specimens of Titanoderma dispar are more delicate than those 

from the colder waters of northern California and northward 

to Alaska. However, like many other crustose corallines on the 

Pacific coast of North America, the species limits of T. dispar are 

in need of elucidation. 

Titanoderma pustulatum (J. V. Lamouroux) Nägeli var. 

pustulatum

Melobesia pustulata J. V. Lamouroux, 1816:315, pl. XII: fig. 2; Adey and 

Lebednik, 1967:39.

Titanoderma pustulatum (J. V. Lamouroux) Nägeli in Nägeli and C. E. Cramer, 1858:532; Woelkerling et al., 1985:329, figs. 29 [lectotype], 30–

39; Chamberlain, 1991:26, figs. 2, 4, 7–15, 19–48, 52a–I, 53, 55–81; 

Chamberlain and Irvine, 1994a:96, figs. 39–49; Yoshida, 1998:620, fig. 

3-36C–G. 

Lithophyllum pustulatum (J. V. Lamouroux) Foslie, 1904:8; Campbell and 

Woelkerling, 1990:115, figs. 1, 4; Ramírez and Santelices, 1991:211; 

Dreckmann, 1991:34; Woelkerling and Campbell, 1992:80, fig. 50A; 

Woelkerling, 1996b:227, figs. 100, 101; Riosmena-Rodríguez et al., 

2005b:34.

Dermatolithon pustulatum (J. V. Lamouroux) Foslie, 1898:11; FernándezGarcía et al., 2011:61.

Lithophyllum pustulatum f. ascripticium Foslie, 1907:34; Foslie, 1909:47; 

Nichols, 1909:354, pl. 10: figs. 2, 3, pl. 11: fig. 10, pl. 12: figs. 18–20, 

pl. 13: fig. 28; Woelkerling, 1993:31; Riosmena-Rodríguez and Woelkerling, 2000:327.

Titanoderma ascripticium (Foslie) Woelkerling, Y. M. Chamberlain et P. 

C. Silva, 1985:333; Scagel et al., 1989:262; Stout and Dreckmann, 

1993:14.

Dermatolithon pustulatum f. ascripticium (Foslie) Foslie ex De Toni, 

1924:665; Dawson, 1960b:32, pl. 25: figs. 8, 9; León-Álvarez and 

González-González, 1993:461; Serviere-Zaragoza et al., 1993a:483.

Dermatolithon ascripticium (Foslie) Setchell et L. R. Mason, 1943b:96; 

Mason, 1953:344; Dawson, 1955:275; León-Álvarez and GonzálezGonzález, 1993:461; Serviere-Zaragoza et al., 2007:9.

Fosliella ascriptica (Foslie) G. M. Smith, 1944:224, pl. 50: fig. 7.

Tenarea ascriptica (Foslie) W. H. Adey, 1970:6; Johansen, 1976a:395, fig. 

341; Schnetter and Bula-Meyer, 1982:127, pl. 18: figs. B,C; Stewart and 

Stewart, 1984:143; Dreckmann, 1991:34 [as “Lithophyllum ascripticum”]; Mateo-Cid and Mendoza-González, 1991:20; Bula-Meyer, 

1995:34.

Crusts epiphytic, adherent to and sometimes surrounding 

host; up to 200 μm thick and to 1.2 cm in diameter. Hypothallium of a single layer of obliquely elongated, palisade cells, 

20–80(–115) μm tall and 4–15 μm wide; perithallium weakly developed, also of elongated cells of similar size, 28–60 μm long by 

4–15 μm wide. Epithallial cells small, 5–7 μm tall, 4–7 μm wide.

Tetrasporangial and bisporangial conceptacles protruding, 

200–350(–500) μm outside diameter. Sporangial conceptacle 

roof 3 cell layers thick; top (epithallial) and bottom layer of 

small cells, and a middle layer of vertically elongated cells (cf. 

Dawson, 1960b: pl. 25: fig. 9; Johansen, 1976a: fig. 341).

Habitat. On Corallina, Gelidium, and Pterocladia, 

and probably on other macroalgae; intertidal.

Distribution. Gulf of California: Puerto Peñasco; 

Jalisco. Eastern Pacific: Oregon to California; Isla Guadalupe to 

FIGURE 51. Titanoderma dispar: Epiphytic irregularly shaped 

crusts, some completely surrounding host branches (JN-4112, US 

Alg. Coll.).
NUMBER 96 • 115

Bahía de Ballenas (Baja California Sur); Isla San Benedicto (Islas 

Revillagigedo); Colima to Michoacán; Costa Rica; Chile. Western Pacific: Japan.

Type Locality. France.

Titanoderma pustulatum var. confine (P. Crouan et H. Crouan) 

Y. M. Chamberlain

Melobesia confinis P. Crouan et H. Crouan, 1867:150; Chamberlain, 

1991:50, figs. 155–158 [lectotype]; Woelkerling, 1998:369; Woelkerling et al., 1998:606, fig. 318.

Titanoderma pustulatum var. confine (P. Crouan et H. Crouan) Y. M. 

Chamberlain, 1991:50, figs. 59–204; Chamberlain and Irvine, 

1994a:102, figs. 43–46; Mendoza-González and Mateo-Cid, 

1996a:24, figs. 8–12; Babbini and Bressan, 1997:181; Mateo-Cid et 

al., 2006:56.

Lithophyllum hapalidiodides f. confine (P. Crouan et H. Crouan) Foslie, 

1909:12 [as “confinis”]; Lemoine, 1913:137, fig. 3; Foslie, 1929: pl. 

72: fig. 7.

Tenarea confinis(P. Crouan et H. Crouan) W. H. Adey et P. J. Adey, 1973:393.

Titanoderma confine (P. Crouan et H. Crouan) J. H. Price, D. M. John et 

G. W. Lawson, 1986:86.

Crusts epiphytic; initially discoid, becoming orbicular to 

confluent, surface flat to imbricate; expanding up to 1 cm or 

more, sometimes overlapping other thalli; up to 600(–900) μm 

thick; margins entire; loosely to moderately attached to host 

algae. Basal (hypothallium) filaments a single layer of oblique 

palisade cells, 25–125 μm long and 11–22 μm wide. Erect filaments (perithallium) either absent or, in some, up to 14 cells 

in length. Epithallial cells more or less triangular, rectangular, 

or domed. Trichocytes present, occasional in basal and erect 

filaments.

Sporangial conceptacles not seen in Gulf (as reported from 

Pacific Mexico [Mendoza-González and Mateo-Cid, 1996a]: 

320–360 μm in outside diameter; tetrasporangia 66–75 μm tall, 

27–45 μm in diameter). Bisporangial conceptacles widely spaced 

to dense, rounded-conical, protruding over surface, distinct periphery or sometimes a rim at base; 400–500 μm in diameter; 

chamber floor 2–3 cell layers below crust surface; chambers 

hemispherical to elliptical, 90–230 μm tall, 240–420 μm wide; 

roof of 3–5 (or more) cell layers, cells not in consistent arrangement by size; chamber with up to 60 bisporangia per conceptacle; 

bisporangia 62–104 μm long, 25–52 μm in diameter. Gametangial conceptacles not observed.

Habitat. Epiphytic on various algae, notably corallines, and rocks, stones, or shells; intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco; 

Jalisco. Eastern Pacific: northern Washington to Baja California 

Sur; Isla Guadalupe; Isla San Benedicto (Islas Revillagigedo); Colima; Oaxaca; Colombia; Chile. Western Pacific: Japan.

Type Locality. Presumably near Brest, Finistère, 

France (Chamberlain, 1991).

Remarks. Titanoderma pustulatum var. confine is 

one of the taxonomic varieties of T. pustulatum recognized by 

Irvine and Chamberlain (1994). The northern Gulf specimens 

(Mateo-Cid et al., 2006) should be molecularly compared with 

type locality material.

Corallinaceae subfam. Hydrolithoideae

Corallinaceae subfam. Hydrolithoideae A. Kato et M. Baba, in Kato, Baba 

and Suda, 2011:669.

Calcified crusts have lateral cell fusions joining cells of 

contiguous filaments. Trichocytes are present, but not in large, 

tightly packed horizontal fields. Secondary pit connections are 

absent, and the basal layer is without palisade cells. Sporangial 

conceptacles are produced both by filaments that are peripheral 

to the fertile area and interspersed among tetrasporangia and 

bisporangial initials. Spermatangial filaments develop on the 

chamber floor of the spermatangial conceptacle.

The C. subfam. Hydrolithoideae is represented by Hydrolithon in the northern Gulf of California (included in the Key 

with C. subfam. Mastophoroideae).

Hydrolithon (Foslie) Foslie

Goniolithon subgen. Hydrolithon Foslie, 1905b:7.

Hydrolithon (Foslie) Foslie, 1909:55; Bittner at al., 2011:710.

Crustose calcified thalli, which form thin crusts mostly on 

other algae, and are two or more cell layers thick, or may be 

thicker crusts with some becoming unattached rhodoliths. Thalli 

are primarily dimerous in construction, with a single layer (hypothallium) of nonpalisade basal filaments which may be with 

or without unicellular or multicellular filaments arising perpendicularly from this basal layer, forming the perithallium. Epithallial cells terminate the filaments at the thallus surface, usually a 

single layer with distal walls rounded or flattened (not flared). 

Trichocytes are present and may be singular, in pairs, and/or in 

small horizontal fields, trichocytes usually separated from each 

other by vegetative filaments. Secondary pit connections are absent. Intercellular fusions are present linking cells of adjacent 

filaments.

Sporangial and gametangial conceptacles are uniporate. The 

pore canals of tetrasporangial and bisporangial conceptacles are 

lined by elongate cells that do not protrude into the pore canal 

and are oriented somewhat perpendicularly to the roof surface. 

Each zonate tetrasporangium or bisporangium is without an apical plug. Gametophytes monoecious or dioecious. Gonimoblast 

filaments develop from the peripheral surface (margins) of the 

central fusion cell in the carposporangial conceptacles. Spermatangial filaments are unbranched and develop from the conceptacle chamber floor.

Remarks. Hydrolithon is distinguished from Heteroderma by the presence of large trichocytes. Penrose and 

Woelkerling (1988) merged the genera Hydrolithon (Foslie) Foslie (1909) and Porolithon Foslie (1909) with Spongites Kützing 

(1841). Later, Penrose and Woelkerling (1992) recognized Spongites but concluded that Hydrolithon was a discrete genus. Many 

recent treatments recognize the three to be distinct genera (cf. 
116 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Guiry and Guiry, 2008–2010). Woelkerling et al. (2012) concluded that anatomical characters alone could not separate two 

of the genera, referring to them as the “Hydrolithon–Porolithon

complex,” and stated that more morphological, anatomical, and 

molecular data were needed to better delineate this complex. In 

finding molecular support for its generic separation, Bittner et 

al. (2011) restricted Hydrolithon to include species having dimerous thallus construction and trichocytes that are singular, in 

pairs, and/or in small horizontal fields and usually interspersed 

with normal vegetative filaments. Bittner et al. (2011) also recognized Porolithon for species with a primarily monomerous thallus construction and trichocytes in large horizontal rows without 

any normal vegetative filaments between individual trichocytes. 

On the basis of these generic boundaries, Bittner et al. (2011) 

also suggested that some species of Hydrolithon should be reassigned to the genus Porolithon.

Two species have been reported in the southern Gulf of California from Bahía de La Paz: Hydrolithon chamaedoris (Foslie et M. Howe) M. J. Wynne (2005; basionym: Lithophyllum 

chamaedoris Foslie et M. Howe, 1906; =Heteroderma chamaedoris (Foslie et M. Howe) E. Y. Dawson, 1960a) by RiosmenaRodríguez and Paul-Chávez (1997, as Fosliella chamaedoris

(Foslie et M. Howe) M. Howe, 1920); and H. reinboldii (Webervan Bosse et Foslie) Foslie (1909; basionym: Lithophyllum reinboldii Weber-van Bosse et Foslie in Foslie, 1901b; Verheij and 

Woelkerling, 1992) by Cruz-Ayala et al. (2001). 

Two species of Hydrolithon are recognized in the northern 

Gulf of California.

KEY TO THE SPECIES OF HYDROLITHON AND “FOSLIELLA” IN THE NORTHERN GULF OF CALIFORNIA

1a. Crusts thicker; of multiple cell layers, typically 400–800 μm thick (sometimes up to 1 mm thick) . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydrolithon samoënse

1b. Crusts much thinner; of 1–3 cell layers in vegetative portions, less than 25 μm thick . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Crusts usually overgrowing or overlapping each other; sporangial conceptacles, 200–225 μm in outside diameter . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydrolithon farinosum

2b. Crusts not usually overgrowing each other; sporangial conceptacles smaller, 100–160 μm in diameter . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fosliella? paschalis

Hydrolithon farinosum (J. V. Lamouroux) D. Penrose et 

Y. M. Chamberlain

FIGURE 52

Melobesia farinosa J. V. Lamouroux, 1816:315, pl. 12: fig. 3; Okamura, 

1936:506; Hamel and Lemoine, 1953:102, fig. 64, pl. 21: figs. 1, 2; 

Masaki and Tokida, 1960:39, pl. 1: figs. 4, 5, pl. 2: figs. 8–12, pls. 6, 7; 

Adey and Lebednik, 1967:32; Chamberlain, 1983:343, fig. 19.

Hydrolithon farinosum (J. V. Lamouroux) D. Penrose et Y. M. Chamberlain, 1993:295, figs. 2–19; Irvine and Chamberlain, 1994:123, figs. 

3A, 54, 55; Riosmena-Rodríguez and Paul-Chávez, 1997:71; Yoshida, 

1998:559; Rodríguez-Morales and Siqueiros-Beltrones, 1999:23; 

L. Aguilar-Rosas et al., 2000:131; Riosmena-Rodríguez and Woelkerling, 2000:339; CONANP, 2002:139; Fragoso and Rodríguez, 

2002:119, figs. 20, 21; L. Aguilar-Rosas et al., 2002:234; Mateo-Cid et 

al., 2006:56; Serviere-Zaragoza et al., 2007:9; Y.-P. Lee, 2008:194, figs. 

A–D; Mendoza-González et al., 2009:223, figs. 3, 4. 

Fosliella farinosa (J. V. Lamouroux) M. Howe, 1920:587; Hamel and Lemoine, 1953:102, fig. 64, pl. 21, figs. 1, 2; Dawson, 1960b:30, pl. 21: fig. 1, 

pl. 22: fig. 1; Masaki, 1968:21; Huerta-Múzquiz and Tirado-Lizárraga, 

1970:128; Chávez-Barrear, 1972b:269; Huerta-Múzquiz and GarzaBarrientos, 1975:8, 11; Chamberlain, 1977:343; Coppejans, 1978:55; 

Johansen, 1981:34: figs. 19A,B, 45: fig. 4A; Chamberlain, 1983:343, 

fig. 19 [lectotype]; Tseng, 1983:76, pl. 41: fig. 4; Stewart and Stewart, 

1984:143; Mendoza-González and Mateo-Cid, 1986:423; SalcedoMartínez et al., 1988:83; Ramírez and Santelices, 1991:205; Dreckmann, 1991:34; León-Álvarez and González-González, 1993:461; 

Serviere-Zaragoza et al., 1993a:483; Mendoza-González and MateoCid, 1994:51; González-González et al., 1996:397.

Crusts epiphytic, very delicate, thin, of 2–3 cell layers, flat 

with a smooth surface; initially suborbicular, up to 4 mm broad, 

up to 20 μm thick, crust margins rounded, lobed; later expanding, up to 1–2 cm (or more), often overlapping or overgrowing 

each other, up to 90 μm thick. Single basal layer of branched filaments with quadrangular cells, in surface view 15–30 μm long 

by 5.0–15 μm in diameter; cell fusions present. Epithallium a 

single layer of rounded cells. Trichocytes frequent throughout 

crust, often terminating a basal filament; single, 20–30 μm tall 

by 13–16 μm in diameter (Figure 52B).

Reproductive conceptacles uniporate; protruding above surface. Sporangial conceptacles 85–100 μm tall, 180–250 μm outside diameter; chamber 140–165 μm inside diameter; roof of 2–3 

cell layers, about 15 μm thick; pore canal about 30 μm long and 

to 12 μm in diameter, lined with nonprotruding and more or less 

vertically oriented cells; tetrasporangia usually peripheral to central columella; zonately divided, (35–)70–80 μm tall, (20–)40–50 

μm in diameter. Gametangial conceptacles smaller; monoecious; 

carpogonia and spermatangia in separate conceptacles. Carposporangial conceptacles chambers 40–105 μm tall, 75–205 μm 

inside diameter; conceptacle roof of 3–6 cell layers, 10–21 μm 

thick; gonimoblast filaments develop from fusion cell margins 

(peripheral surfaces); carposporangia 25–50 μm long, 24–40 μm 

in diameter. Spermatangial conceptacle chamber 11–40 μm tall, 

45–75 μm inside diameter; conceptacle roof of 3 cell layers, roof 

pore about 6–12 μm in diameter, with mucilaginous spout extending to about 12 μm in length; spermatangial filaments produced only from chamber floor (gametangia not known in Gulf; 

after Mendoza-González et al., 2009, for Atlantic and Caribbean 

Mexico).

Habitat. Epiphytic on other algae, especially Padina, 

Dictyota, Dictyopteris, and Sargassum, and should be looked for 
NUMBER 96 • 117

on sea grasses as well; mid intertidal to shallow subtidal, down 

to 5 m depths.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Isla Tiburón; Bahía de Loreto; Punta 

Palmilla to Cabeza Ballena; Isla María Cleofa (Islas Marías; Islas 

Tres Marías); Nayarit to Jalisco. Eastern Pacific: Isla Guadalupe; 

Punta Santa Rosaliita (“Punta Santa Rosalía”) to Desembarcadero de Miller (Miller’s Landing), Baja California; Isla Socorro 

(Islas Revillagigedo); Jalisco to Oaxaca; Chile. Western Pacific: 

China; Vietnam; Japan; Korea.

Type Locality. “On Sargassum linifolium, Mediterranean” (Chamberlain, 1994:123); “probably from Adriatic 

Sea” (Dawson, 1960b:30; Chamberlain, 1983:341).

Remarks. Hydrolithon farinosum is presumed to be 

a cosmopolitan species found growing on various benthic algae 

and sea grasses. In the northern Gulf, H. farinosum is often associated with another epiphytic crustose coralline, Heteroderma 

gibbsii; both are sometimes found growing on species of Padina 

and Dictyota.

Melobesia farinosa J. V. Lamouroux (1816) is the type species of the generic name Fosliella M. Howe (1920). Studies by 

Penrose and Chamberlain (1993) determined that the type of 

M. farinosa belonged to the genus Hydrolithon, thus making 

Fosliella M. Howe a heterotypic synonym of Hydrolithon.

Hydrolithon samoënse (Foslie) Keats et Y. M. Chamberlain

Lithophyllum samoënse Foslie, 1906b:20; 1929:38, pl. 53: fig. 19 (lectotype); 

Adey and Lebednik, 1967:17; Masaki, 1968:37, pl. 20: figs. 3, 4, pl. 23: 

figs. 1–4, pl. 61: figs. 3–6, pl. 62: figs. 1–5; Guzmán del Próo et al., 

1972:259; Mendoza-González and Mateo-Cid, 1985:30; 1986:423; 

Ramírez and Santelices, 1991:212; Serviere-Zaragoza et al., 1993a:484; 

Woelkerling, 1993:193; González-González et al., 1996:239; Woelkerling, 1998:324; Woelkerling et al., 1998:493, fig. 205 (paratype).

Hydrolithon samoënse (Foslie) Keats et Y. M. Chamberlain, 1994:15, figs. 

31–54; Chamberlain, 1994:126, figs. 56, 57; Yoshida, 1998:563; 

Riosmena-Rodríguez and Woelkerling, 2000:344; Fragoso and Rodríguez, 2002:123, figs. 27, 28; Bittner et al., 2011:710.

Pseudolithophyllum samoënse (Foslie) W. H. Adey, 1970:13; Tseng, 1983:84, 

pl. 45: fig. 1.

Crusts pink, prostrate and spreading, with a relatively 

smooth surface (sometimes surface appearance somewhat irregular, resulting from uneven surface of substratum), 400–

800(–1100) μm thick; attached to rocks or mollusk shells. In 

vertical section: hypothallium of several layers of rectangular 

FIGURE 52. Hydrolithon farinosum: A. Surface view of decalcified crust showing prominent trichocytes (arrow). B. Surface view of decalcified 

crust showing cells of adjacent filaments conjoined by fusions and trichocytes at ends of filaments (JN-3169, US Alg. Coll.).
118 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

cells, (12–)15–20 μm tall and 5–7(–10) μm wide; perithallium 

forming largest portion of thallus, of small, squarish to rounded 

cells, 4–7 μm in diameter. Cell fusions frequent between cells in 

both hypothallial and perithallial filaments. Epithallium a single layer of rectangular cells, 2.5–4 μm tall and 4–7 μm wide. 

Trichocytes occasional, terminal on erect (perithallial) filaments 

at thallus surface sometimes singular or forming short, loose 

horizontal rows (Fragoso and Rodríguez, 2002).

Sporangial conceptacles in crust surface, convex and slightly 

protruding, each with a single pore; in vertical section, ovoid, 

93–102 μm in diameter, 37–66 μm tall; with zonately divided 

tetrasporangia. Conceptacle roof composed of an epithallial cell 

layer and an inner cell layer of tall thin elongated cells. Enlarged 

pore cells occur at base of conceptacle pore (Fragoso and Rodríguez, 2002). Spermatangial conceptacles in vertical section, 

50–80 μm in diameter.

Habitat. On rocks and shells; mid to low intertidal.

Type Locality. Sataua, Savai’i Island, Samoa (formerly Western Samoa).

Distribution. Gulf of California: Isla Pelícanos 

(Bahía Kino); Nayarit. Eastern Pacific: Isla Cedros (Baja California) to Bahía Tortugas, inside southeast Bahía San Bartolomé 

(Baja California Sur); Colima; Rapa Nui (Easter Island; Isla de 

Pascua). Western Pacific: China; Korea; Japan; Vietnam. Central 

Pacific: Samoa.

Remarks. Hydrolithon samoënse, recorded by 

Mendoza-González and Mateo-Cid (1986), is poorly known 

in the northern Gulf of California. Dawson (1960b, 1961b, as 

Lithophyllum samoënse) noted that his identification of this 

species from Isla Cedros (Pacific Mexico) was questionable and 

that more collections and critical comparisons were needed. A 

similar conclusion was made by Masaki (1968, as L. samoënse) 

who observed Japanese specimens were twice as thick as those of 

Dawson (1960b), and Keats and Chamberlain (1994) also suggested some of the specimens may not be this species. In their description of Hydrolithon samoënse from tropical Pacific Mexico, 

Fragoso and Rodríguez (2002) also noted that Dawson’s (1960b) 

specimens need to be reexamined. In another study, Bittner et al. 

(2011) suggested H. samoënse belongs in the genus Porolithon, 

but Kato et al. (2011) noted that its relationship to Porolithon 

was unresolved. All Gulf of California specimens identified as 

H. samoënse should be critically compared with type material.

Corallinaceae subfam. Mastophoroideae

Corallinaceae subfam. Mastophoroideae Setchell, 1943:134 [as “Mastophoreae”]; Woelkerling, 1996c:237. 

Members include crustose corallines that are prostrate to 

partially erect and may be discoid or spreading with more or less 

smooth to warty surfaces, or with short unbranched to branched 

protuberances. They grow on rocks or other hard substratum, 

some are free-living rhodoliths, and a few are reported to be 

endophytic. Thalli are dimerous (first-order filaments making 

a single layer and second-order filaments arising at right angle 

from the dorsal side of first-order filaments) or monomerous 

(single order of filaments) in construction or both. Some cells of 

adjacent filaments linked by cell fusions. Secondary pit connections are absent in most, or rare (known in one genus, Metamastophora Setchell, 1943). Sporangial conceptacles are uniporate, 

tetrasporangia and bisporangia are without apical plugs. Gametangial thalli, where known, are monoecious or dioecious. Carpogonial and spermatangial conceptacles are uniporate.

Remarks. Gene sequence analyses of Bailey et al. 

(2004) revealed C. subfam. Mastophoroideae to be polyphylectic, belonging to four distinct lineages. Kato et al. (2011) 

restricted the subfamily to include only Mastophora Decaisne 

(1842a; see Keats et al., 2009:417, for summary of genus characters) and Metamastophora Setchell (neither of which have been 

found in the Gulf of California), and left the placement of Spongites and Pneophyllum unresolved until their generitypes could be 

studied. Until the needed studies are completed, for convenience 

the other genera are treated in C. subfam. Mastophoroideae (following Woelkerling, 1996c). Much work remains to clarify the 

molecular systematics and phylogenetic relationships of the genera and species of Pneophyllum, Spongites, and Heteroderma, as 

well as the generic placement of one species of “Fosliella.”

The five genera reported in the northern Gulf of California 

are provisionally retained in the C. subfam. Mastophoroideae.

KEY TO THE GENERA IN C. SUBFAM. HYDROLITHOIDEAE AND THOSE TENTATIVELY 

IN C. SUBFAM. MASTOPHOROIDEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Crusts thin, usually less than 200 μm thick, without protuberances; often epiphytic, not forming free-living rhodoliths 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

1b. Crusts thicker, generally greater than 200 μm thick, may have protuberances; on rocks, epiphytic, or may form free-living 

rhodoliths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Sporangial conceptacle pore canal in vertical section lined with cells parallel to roof that protrude into pore canal; thallus 

construction either monomerous or dimerous, although in some may be both; trichocytes not observed in primigenous 

(first order; basal) filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spongites

2b. Sporangial conceptacle pore canal in vertical section lined with cells perpendicular to roof surface that do not protrude 

into pore canal; thallus construction primarily dimerous (can be monomerous and radially arranged in protuberances); 

trichocytes terminal on primigenous filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hydrolithon (in part) 

3a. Trichocytes absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Heteroderma

3b. Trichocytes present or absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
NUMBER 96 • 119

4a. Trichocytes when present, intercalary within primigenous filaments or terminal on postigenous (second order; erect) 

filaments; pore canal of sporangial conceptacles (in vertical section) lined, at least initially, by horizontally oriented cells 

(parallel to conceptacle roof surface); germination disc with 8-celled center . . . . . . . . . . . . . . . . . . . . . . . Pneophyllum

4b. Trichocytes when present, terminal on primigenous filaments or intercalary on postigenous filaments; pore canal of sporangial conceptacles (in vertical section) lined by enlarged vertically oriented cells (perpendicular to conceptacle roof); 

germination disc with 4-celled center . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5a. Thalli not extensively overlapping each other; sporangial conceptacles 200–225 μm in diameter . . . “Fosliella?” paschalis 

5b. Thalli often overlapping each other; sporangial conceptacles smaller, 100–160 μm in diameter . . . . Hydrolithon (in part) 

Heteroderma Foslie

Heteroderma Foslie, 1909:56. 

Crustose corallines are thin, 2–5 cells layers thick, and found 

growing as epiphytes on other macroalgae. Thallus construction is 

dimerous, composed of basal, first-order (primigenous) filaments, 

and second-order (postigenous) filaments. Trichocytes and secondary pit connections are absent. Intercellular fusions are present. 

Sporangial and gametangial conceptacles open by a single 

pore. In some species a gelatinous spout extends outward from 

pore of the spermatangial conceptacles.

Remarks. Heteroderma is tentatively recognized 

until the genus can be further clarified. The use of a single diagnostic character—the absence of trichocytes in Heteroderma

versus their presence in Hydrolithon—for their generic separation has been questioned by some. It has been suggested that 

presence or absence of trichocytes may reflect an environmental 

response. Others, however, contend that trichocytes represent a 

fundamental phylogenetic difference between these groups (e.g., 

Masaki, 1968:56). In recognizing Heteroderma as a genus, Foslie (1909) did not designate a type species (generitype). Setchell 

and Mason (1943b) later chose H. subtilissimum (Foslie) Foslie 

(1909; basionym: Melobesia subtilissima Foslie, in Weber-van 

Bosse and Foslie, 1904) to lectotypify the genus. Chamberlain 

(1983) examined the type collection of H. subtilissimum (Foslie) 

Foslie and considered it to be a minute Pneophyllum Kützing 

(1843) but did not transfer the species (Woelkerling, 1988). 

For now, the species from the Gulf of California are tentatively referred to Heteroderma until their generic status and 

phylogenetic relationships can be further elucidated, including 

genetic comparisons to the type from the reef at Atjatuning, off 

the west coast of New Guinea. 

Three species of Heteroderma, including two described from 

the Gulf of California, are known to occur in the northern Gulf. 

KEY TO THE SPECIES OF HETERODERMA IN THE NORTHERN GULF OF CALIFORNIA

1a. Crusts mostly a single cell layer; very thin, 7–10 μm thick; sporangial and carpogonial conceptacles small, 70–100 μm 

outside diameter; spermatangial conceptacles conical, small, base 45 μm in diameter, upward narrowed to 25–28 μm in 

diameter, pore often with extending gelatinous spout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. subtilissimum

1b. Crusts initially only 1 cell layer, later developing more cell layers; thicker, 10–50 μm thick; sporangial and carpogonial 

conceptacles slightly larger (mostly more than 90 μm outside diameter); spermatangial conceptacles not conical, pore 

without extending gelatinous spout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Crusts 25–50 μm thick, of 2–4 vegetative cell layers; reproductive portions of 10–12 cell layers and up to 100 μm thick; 

sporangial conceptacles up to 200 μm outside diameter, chamber about 100 μm inside diameter,70 μm tall; carposporangial conceptacle chambers 90 μm inside diameter, 80 μm tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. corallinicola

2b. Crusts mostly thinner, 10–30 μm thick, of 1–2 vegetative cell layers, reproductive and older portions of 3–5 cell layers; 

sporangial conceptacles larger, 250–300 μm outside diameter, chamber 210 μm inside diameter, 105 μm tall; carposporangial conceptacles larger, 225–275 μm outside diameter, chambers 140–200 μm inside diameter . . . . . . H. gibbsii

Heteroderma corallinicola E. Y. Dawson

FIGURE 45B

Heteroderma corallinicola E. Y. Dawson, 1944a:273, pl. 63: fig. 2; 1960b: 

53, pl. 48: fig. 2; 1961b:417; González-González et al., 1996:224; 

Riosmena-Rodríguez and Woelkerling, 2000:327.

Crusts epiphytic, minute, closely adherent on surfaces of 

host; monostromatic only in marginal portions; centrally, 25–50 

μm thick, usually of 2–4 layers of quadrangular cells, 9–14 μm 

in diameter; reproductive portions up to 100 μm thick, up to 

10–12 cell layers. Hypothallium of slightly horizontally broadened cells, up to 14 μm wide. Perithallium layers of squarish to 

slightly vertically elongated cells. Trichocytes absent.

Sporangial conceptacles dome shaped, up to 200 μm outside 

diameter; chamber about 100 μm inside diameter and 70–90 μm 

tall, with concave floor of 2 or more cell layers; tetrasporangia 

faintly divided or appearing undivided (possibly immature), up 

to 70 μm long, 30 μm in diameter. Carposporangial conceptacles 

more or less hemispherical; chambers about 90 μm in diameter, 

about 80–90 μm tall, with concave floor of 3 or more cell layers. 

Spermatangial conceptacles prominent, chamber 50–60 μm inside diameter, 40–50 μm tall, with a flat to slightly concave floor.

Habitat. Epiphytic on Corallina on rocks and in tide 

pools; mid to low intertidal.

Distribution. Gulf of California: Guaymas. 
120 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Type Locality. On Corallina in tide pools; cove 

north of Cabo Arco, Guaymas, Sonora, Gulf of California, 

Mexico. 

Remarks. Dawson (1960b) commented the Gulf 

endemic Heteroderma corallinicola grows on Corallina, has 

tetrasporangia, and is morphologically very similar to the western Atlantic H. chamaedoris (Foslie et M. Howe) E. Y. Dawson (1960b; basionym: Lithophyllum chamaedoris Foslie et 

M. Howe, 1906). Heteroderma chamaedoris, described from 

the Bahama Islands, is epiphytic on the green alga Chamaedoris 

peniculum (J. Ellis et Solander) Kuntze (1898) and has bisporangia. Apparently the type of sporangia, different algal hosts, 

and geographical separation are the primary differences between 

these two species.

Heteroderma gibbsii (Setchell et Foslie) Foslie

FIGURES 53, 54

Melobesia gibbsii Setchell et Foslie in Foslie 1907:26; Woelkerling 1993:106.

Heteroderma gibbsii (Setchell et Foslie) Foslie, 1909:56; Dawson, 1944a:272; 

1959a:20; 1960b:54, pl. 21: figs. 4–6, pl. 23: fig. 2; 1961b:417; 

1966a:19; Adey 1970:16; González-González et al., 1996:224; 

Riosmena-Rodríguez and Paul-Chávez, 1997:71; Riosmena-Rodríguez 

and Woelkerling, 2000:339; CONANP, 2002:139; Pacheco-Ruíz and 

Zertuche-González, 2002:467; Pacheco-Ruíz et al., 2008:208.

Coralline crusts, initially suborbicular in surface view, 

with lobed margins; basically monostromatic in young crusts 

and margins, thin, up to 30 μm thick; later becoming irregular in outline and increasing to 3–4 cell layers in reproductive 

and older portions; epiphytic on various brown and red algae; 

numerous individuals can cover extensive portions of host alga, 

usually with little overlap of one another. Hypothallium parallel 

to substratum, a single layer of filaments of horizontal elongated 

cells (11–16 μm long, 6–12 μm wide). Perithallium of 2–4 cell 

layers of squarish cells (about 7–12 μm in diameter); the uppermost layer of vertically elongated cells, 11–16 μm long, 6–12 μm 

in diameter. Epithallium irregularly developed, a single layer of 

small cells 2–4 μm high and 6–10 μm wide. Trichocytes absent.

Sporangial conceptacles dome-shaped above crust surface, 

250–300 μm outside diameter; chamber 210 μm inside diameter 

and 105 μm tall, with floor of 1–2 cell layers; zonate tetrasporangia about 50 μm long. Carposporangial conceptacles 225–275 

μm outside diameter; chambers 140–160(–200) μm inside diameter, 40–70 μm tall, with floor of 1–2 cell layers. Spermatangial 

conceptacles only slightly prominent; chambers 40–50 μm inside 

diameter, (12–) 16–30 μm tall. 

Habitat. Epiphytic on various red and brown algae, 

including Dictyota, Padina, Sargassum, Gracilaria, and Laurencia; often found growing along with other epiphytic species of 

crustose corallines on same host; intertidal (although probably 

restricted to the intertidal zone, it has also been dredged from 

40 m depth; Dawson, 1944a).

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas; Puerto Refugio, Isla Angel de la Guarda and Isla 

Turner (Islas de la Cintura); Isla San José to San José del Cabo.

Syntype Localities. Epiphytic on Sargassum: Isla 

San José (25o00’N; 110o38’W), and Isla Espíritu Santo (east of 

Bahía de La Paz: 24o30’N; 110o22’W), Baja California Sur, Gulf 

of California, Mexico.

Remarks. Dawson (1960b) observed that Gulf of 

California endemic Heteroderma gibbsii could resemble some 

Pneophyllum nicholsii. The most apparent differences are 

that H. gibbsii has larger sporangial conceptacles and smaller 

spermatangial conceptacles than those of P. nicholsii. Dawson 

(1960b) suggested the La Paz specimen identified by Mason 

(1953) as “H. nicholsii” [non H. nicholsii Setchell et L. Mason, 

1943b; now P. nicholsii (Setchell et L.R. Mason) P. C. Silva et 

P. W. Gabrielson, in Gabrielson et al., 2004] was in all probability also H. gibbsii.

Heteroderma subtilissimum (Foslie) Foslie

FIGURE 55

Melobesia subtilissima Foslie in Weber-van Bosse and Foslie, 1904:55; Foslie, 

1905b:8; Chamberlain, 1983:312; Woelkerling, 1993:218.

Heteroderma substilissimum (Foslie) Foslie, 1909:56; Dawson, 1956:48, 

fig. 41; 1960b:58, pl. 49: figs. 5, 6; 1961b:417; 1966a:20; Adey, 

1970:17; Stewart and Stewart, 1984:143; Dreckmann 1991:34, as 

“Pneophyllum subtilissima”; González-González et al., 1996:225; 

Riosmena-Rodríguez and Woelkerling, 2000:345; Fernández-García 

et al., 2011:62.

Crusts minute, epiphytic on various algae; initially more 

or less discoid, later forming lobed crusts up to 2 mm wide, 

very thin, 7–9 μm thick. Vegetative portion of crust essentially 

monostromatic; in vertical section, quadrangular cells squarish 

to rounded to slightly horizontally elongated, 7–12 μm in diameter; cells in surface view 11–17 μm long, 7–12 μm wide, 

arranged in radiating rows. Crust thicker near conceptacles. 

FIGURE 53. Heteroderma gibbsii: Habit of irregularly shaped crust 

epiphytic on Padina, mostly monostromatic, except for conceptacles 

(EYD-457, AHFH, now UC).
NUMBER 96 • 121

Erect filaments (perithallial and epithallial cells) mostly absent. 

Trichocytes absent.

Sporangial conceptacles dome-shaped, 70–100 μm in outside diameter; chamber 45–60 μm in diameter, with flat floor of 

one cell layer; tetrasporangia zonate, about 25 μm tall, 14–17 μm 

in diameter. Carposporangial conceptacles also dome-shaped, 

60–90 μm in outside diameter, nonrostrate to slightly rostrate. 

Spermatangial conceptacles small, conical, about 45 μm wide at 

base, narrowing upward to 25–28 μm in diameter; ostiolate with 

a gelatinous spout, up to 25 μm long (after Dawson 1960b).

Habitat. Epiphytic on Cladophoropsis, Halimeda,

leaf-like blades of Sargassum, Jania, and probably other algae as 

well; intertidal to shallow subtidal. 

Distribution. Gulf of California: Punta Pelícano, 

Puerto Peñasco; Bahía San Gabriél, Isla Espíritu Santo to Cabo 

Pulmo. Eastern Pacific: Isla Guadalupe (off Baja California); El 

Salvador. 

type Locality. Epiphytic on Corallina pilifera; reef 

off Atjatuning, west coast of New Guinea (Dawson, 1960b; Verheij and Woelkerling, 1992).

Remarks. The taxonomic status of Gulf of California specimens referred to H. subtilissima is in need of further 

elucidation (see also Remarks for Heteroderma).

Fosliella M. Howe

Fosliella M. Howe, 1920:587.

Algae are thin, calcified crusts, usually less than 200 μm 

thick, and epiphytic and firmly adherent on various macroalgae 

and seagrasses. Internally (as seen in vertical section), they are 

dorsiventrally organized and dimerous, composed of two types 

of filaments. Primigenous (first order) filaments form a single 

layer growing parallel (horizontal) on the host; and postigenous 

(second order) filaments grow more or less upward (vertical). 

Erect filaments may sometimes consist of only a single epithallial cell. Cells in adjacent filaments are sometimes joined by cell 

fusions, secondary pit connections are unknown. Trichocytes are 

sometimes present as terminal cells of the first-order filaments or 

intercalary in second-order filaments.

Tetrasporangia and sometimes bisporangia are developed 

within uniporate conceptacles, without apical sporangial plugs. 

Each spore germinates into a characteristic 4-celled sporeling, 

 FIGURE 54. Heteroderma gibbsii: A. Transection through algal host and decalcified crust with tetrasporangial conceptacle (JN & HWJ73-7-22c, US Alg. Coll.). B. Transection through algal host and decalcified crust with tetrasporangial conceptacle (JN & HWJ-73-7-15, 

US Alg. Coll.). 

FIGURE 55. Heteroderma subtilissimum: A. Transection through 

mature tetrasporangial conceptacle. B. Surface view of portion of 

crust (A, B, after Dawson, 1960a: pl. 49: figs. 5,6).
122 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

which then continues to develop the crustose thallus. Gametangia are poorly known.

Remarks. The taxonomic status of the genus Fosliella is problematic, since the generitype of Fosliella M. Howe 

(1920), F. farniosa (J.V. Lamouroux) M. Howe, has been considered to be a Hydrolithon, i.e., H. farinosum (J.V. Lamouroux) D. 

Penrose et Y.M. Chamberlain (1993). If these two are recognized 

as being congeneric, then the generic placement of the other species of “Fosliella” is in question, and those not already studied 

need to be reinvestigated, including the type of F. paschalis (Me. 

Lemoine) Setchell et N. L. Gardner, i. e., Melobesia paschalis 

Me. Lemoine (in Børgesen, 1924). Johansen (in Guiry and Guiry, 

2009) commented that Fosliella is most closely related to Pneophyllum and Spongites. 

There is one reported species of “Fosliella” in the northern 

Gulf of California (included in “Key to Genera of C. subfam. 

Mastophoroideae”).

Fosliella? paschalis (Me. Lemoine) Setchell et N. L. Gardner

Melobesia paschalis Me. Lemoine in Børgesen, 1924:289, figs. 32f,g; Santelices and Abbott, 1987:8; Andersson and Athanasiadis, 1992:31; Woelkerling, 1998:378; Woelkerling et al. 1998:624, fig. 336.

Fosliella paschalis (Me. Lemoine) Setchell et N. L. Gardner, 1930:176; Dawson, 1959c:4; 1960b:31; 1961b:415; Hollenberg, 1970:65; Johansen, 1976a:399, fig. 345; Stewart and Stewart, 1984:143; MendozaGonzález and Mateo-Cid, 1986:423; Afonso-Carrillo, 1989:331, figs. 

1–10 (holotype), 11–27; Sánchez-Rodríguez et al., 1989:42; R. AguilarRosas et al., 1990:124; Ramírez and Santelices, 1991:205; Dreckmann, 

1991:35; Mendoza-González and Mateo-Cid, 1992:18; Andersson 

and Athanasiadis, 1992:32; León-Álvarez and González-González, 

1993:461; Serviere-Zaragoza et al., 1993a:483; Stout and Dreckmann, 1993:14; Mateo-Cid et al., 1993:46; Mendoza-González and 

Mateo-Cid, 1994:51; González-González et al., 1996:397; Woelkerling, 1998:378; Rodríguez-Morales and Siqueiros-Beltrones, 1999:23; 

Riosmena-Rodríguez and Woelkerling, 2000:343; Fernández-García et 

al., 2011:61.

Crustose coralline, epiphytic on other macroalgae; crusts 

forming pink, prostrate patches, broadening up to a few mm in 

width, with rounded or lobed margins (not becoming superimposed), or may encircle algal host; monostromatic and very thin, 

irregularly arranged in more or less radiating rows, usually less 

than 25 μm thick in vegetative portions; with more cell layers 

in the vicinity of conceptacles. Cells in surface view, rounded, 

more or less quadrangular or irregular, 11–15 μm long, 7–8 μm 

wide, sometimes with cell fusions between cells of contiguous 

filaments. Trichocytes present, often frequent.

Sporangial conceptacles often crowded over surface; hemispherical to dome shaped, 100–160 μm in diameter, with a single 

pore; bisporangia and tetrasporangia up to about 60 μm long. 

Gametangial conceptacles not observed (after Dawson, 1960b).

Habitat. Epiphytic on Laurencia and Pterocladiella

and probably other macroalgae; mid to low intertidal.

Distribution. Gulf of California: Bahía Kino; 

Bahía Concepción; Isla San Ildefonso to Punta Palmilla; Nayarit 

to Jalisco. Eastern Pacific: Laguna Beach, southern California 

to Bahía Magdalena, Baja California Sur; Islas Todos Santos 

and Isla Guadalupe, off Baja California; Isla Clarión (Islas Revillagigedo); Colima to Oaxaca; Isla Clipperton; La Perouse to 

Hanga Piko, Rapa Nui (Easter Island; Isla de Pasqual), Chile.

Type Locality. Hanga Piko, Rapa Nui (Easter Island; Isla de Pasqual), Valparaíso Region, Chile.

Remarks. Fosliella? paschalis is included in the “Key 

to Species of Hydrolithon and Fosliella” (see herein under Hydrolithon). The generic status of the taxon F.? paschalis, as well 

as specimens from the Gulf of California referred to the species, 

should be reinvestigated (see also Remarks under Fosliella). Until 

its generic status is resolved, its placement remains uncertain.

Pneophyllum Kützing

Pneophyllum Kützing, 1843:385; Penrose and Woelkerling, 1991:495; Penrose, 1996b:266.

Calcified crusts are without protuberances, mostly epiphytic on other algae and seagrasses but some may grow on 

rocks, and strongly adhere to host or substratum by cell adhesion. Crusts are pseudoparenchymatous, some less than 200 μm 

thick and of 2–3(–5) cell layers, and others much thicker, of 

numerous cell layers in vegetative parts. Crusts develop from 

a germination disc with an 8-celled center. Crusts are dorsiventrally organized and dimerous in construction, with 2 orders 

of filaments; the first-order (primigenous) filaments produce a 

unistratose basal layer (hypothallium) of nonpalisade cells that 

gives rise to second-order (postigenous) filaments that grow 

perpendicular (usually more or less erect) to the substratum or 

host and form the perithallium. The erect filaments are either 

unicellular, consisting only of an epithallial cell, or multicellular with subepithallial meristematic cells of the filaments issuing 

epithallial cells toward the thallus surface and vegetative cells 

inward. Some cells in adjacent erect filaments are joined by cell 

fusions; secondary pit connections are absent. Outermost walls 

of epithallial cells are rounded or flattened, not flared. Trichocytes, when present, are intercalary within first-order filaments 

or terminal on second-order filaments; single or in groups at the 

crust surface.

Sporangial conceptacles are uniporate and are more or less 

even with or sunken below the crustal surface. Bisporangia or 

zonately divided tetrasporangia are developed over the chamber 

floor or peripheral to a central columella, and lack apical plugs. 

The conceptacle roof is formed by filaments that are peripheral to or interspersed between the sporangial initials. The pore 

canal is surrounded by numerous cells that are oriented parallel to the conceptacle roof or with upward extending filaments. 

Gametangial thalli are dioecious or monoecious (carpogonia 

and spermatangia rarely in the same conceptacle). Carposporophytes with carposporangia that develop on short gonimoblast 

filaments that arise from the peripheral margins of a large central 

fusion cell. Spermatangial conceptacles with unbranched spermatangial filaments produced from the chamber floor.
NUMBER 96 • 123

Remarks. Pneophyllum is differentiated from the 

genera Fosliella and Spongites by its 8-celled sporeling and by 

trichocytes that are intercalary in first-order filaments. However, molecular studies are needed to further evaluate the species and the distinction of these genera. At least one member 

of the genus consists of unconsolidated filaments, i.e., Pneophyllum confervicolum f. minutulum (Foslie) Y. M. Chamberlain 

(1983; basionym: Melobesia minutulum Foslie, 1904; =Heteroderma minutula (Foslie) Foslie, 1909; Fosliella minutula (Foslie) 

Ganesan, 1963).

Two species are reported in the southern Gulf of California 

and Pacific Mexico. Pneophyllum confervicolum (Kützing) Y. M. 

Chamberlain (1983; basionym: Phyllactidium confervicola Kützing, 1843) is recorded from Bahía de La Paz (Huerta-Múzquiz 

and Mendoza-González, 1985, as Heteroderma minutula; 

Riosmena-Rodríguez and Paul-Chávez, 1997; Mateo-Cid and 

Mendoza-González, 2009), Bahía San Quintín (R. Aguilar-Rosas 

et al., 2005) and Isla Guadalupe (Baja California), Bahía Tortugas, inside southeast Bahía San Bartolomé (Baja California Sur) 

(Dawson, 1960b), Michoacán (Stout and Dreckmann, 1993), 

and Oaxaca (Dawson, 1960b; Huerta-Múzquiz and TiradoLizárraga, 1970). The Pacific Mexico species Pneophyllum conicum (E. Y. Dawson) Keats, Y. M. Chamberlain et Baba (1997a; 

basionym: Hydrolithon conicum E. Y. Dawson, 1960b; type locality: Isla Socorro, Islas Revillagigedo) has also been reported 

from Bahía de La Paz (Cruz-Ayala et al., 2001), Punta Arena and 

Cabo Pulmo, and Nayarit to Jalisco (Mateo-Cid et al., 2000; 

Mateo-Cid and Mendoza-González, 2009).

Two species of Pneophyllum are reported in the northern 

Gulf of California.

KEY TO THE SPECIES OF PNEOPHYLLUM IN THE NORTHERN GULF OF CALIFORNIA

1a. Crusts thin, mostly 15–20 μm thick; sporangial conceptacle pore without extending upward filaments; sporangial conceptacle without columella; sporangial and carposporangial conceptacles not as wide, 60–100 μm in inside diameter, 

40–50 μm tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. fragile

1b. Crusts thicker, usually 30–50(–100) μm (or more) thick; conceptacle pore with extending upward filaments; sporangial 

conceptacle with columella; sporangial and carposporangial conceptacles larger, 160–210 μm inside diameter, 75–90 μm 

tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. nicholsii

Pneophyllum fragile Kützing

Pneophyllum fragile Kützing, 1843:385; 1869: pl. 93: figs. a–c; Chamberlain, 1983:356, figs. 24–27; Penrose and Woelkerling, 1991:495, figs. 

2–27; Chamberlain, 1994:141, figs. 64, 65; Penrose, 1996b:269, fig. 

123; Yoshida, 1998:609; Mendoza-González and Mateo-Cid, 1999:42, 

fig. 6; Mateo-Cid et al., 2000:65; Mateo-Cid and Mendoza-González, 

2003:11; Fragoso and Rodríguez, 2002:126, figs. 29–31; Mateo-Cid 

et al., 2006:56; Mateo-Cid and Mendoza-González, 2009:610, figs. 

13–16, 21.

Melobesia lejolisii Rosanoff, 1866:62, pl. 1: figs. 1–13, pl. 7: figs. 9–11; Suneson, 1937:7, figs. 1–5; Suneson, 1943:23, pl. 4: fig. 18, pl. 5: fig. 21.

Heteroderma lejolisii (Rosanoff) Foslie, 1909:56 [generitype of Heteroderma]; Dawson, 1960b:55, pl. 50: figs. 4–6;, 1961b:417; GonzálezGonzález et al., 1996:317.

Fosliella lejolisii (Rosanoff) M. Howe, 1920:588; Masaki, 1968:23, pls. 

12, 49, 50; Huerta-Múzquiz and Tirado-Lizárraga, 1970:128; Tseng, 

1983:78, pl. 42: fig. 1; Dreckmann, 1991:34; González-González et al., 

1996:311.

Pneophyllum lejolisii (Rosanoff) Y. M. Chamberlain, 1983:359, figs. 28–32; 

González-González et al., 1996:121.

Crusts very thin, small, purple-pinkish, of epiphytic, 1–2 cell 

layers in vegetative portions, 15–20 μm thick; 3–5 cell layers in 

reproductive regions, 20–30(–45) μm thick; initially subdiscoid 

(suborbicular), 2–4 mm in diameter; later expanding, occasionally covering most of host, often overlapping; firmly attached to 

host algae or sea grass by cell adhesion. Hypothallium a single, 

basal layer of first order filaments parallel to host; of squarish 

to slightly rectangular (nonpalisade) cells, (7–)10–13 μm long, 

(6–)10–12 μm in diameter. Perithallium of single cell layer or 

multicellular layers of second order simple or branched filaments 

more or less perpendicular to hypothallial filaments; of cells (3–)5–

11 μm tall, 5–14 μm in diameter. Cell fusions common, secondary pit connections absent. Epithallium a single layer of small cells, 

3–6 μm tall and 4–7 μm wide, terminal on perithallial filaments at 

thallus surface. Trichocytes absent, or if present, usually singular at 

surface, seen in surface view 15–19 μm long, 10–12 μm in diameter. 

Reproductive conceptacles with roof slightly protruding or 

more or less even with crust surface. Sporangial conceptacles 

uniporate, convex, protruding; inside chamber with or without 

columella, 40–80 μm tall, 130–160 μm in diameter; bisporangia 

or tetrasporangia on floor, 30–48 μm long, 22–29 μm in diameter. Carposporangial conceptacles more or less even with crust 

surface; with chambers (30–)50–150 μm tall and 110–200 μm in 

diameter, with tall cells at conceptacle periphery; carposporangia 

25–42 μm long, 30–45 μm in diameter. Spermatangial conceptacle chambers (30–)45–90 μm tall, (55–)80–110 μm in diameter; 

spermatangial filaments only develop from floor of chamber; pore 

of spermatangial conceptacle with a protruding, elongated mucilaginous tube (after Penrose, 1996b).

Habitat. Epiphytic on algae, such as Padina, and 

seagrasses; intertidal.

Distribution. Gulf of California: Puerto Peñasco; 

Punta Arena to Cabo Pulmo. Eastern Pacific: Bahía San Quintín, 

Baja California; Colima; Oaxaca. Western Pacific: China; Korea; 

Japan.

Type Locality. On Sphaerococcus coronopifolius; 

from an unknown locale in the Mediterranean Sea (Chamberlain, 1983).
124 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Remarks. Pneophyllum fragile is the type species of 

the genus (Chamberlain, 1983:356, figs. 26, 27).

Pneophyllum nicholsii (Setchell et L. R. Mason) P. C. Silva et 

P. W. Gabrielson

Heteroderma nicholsii Setchell et L. R. Mason, 1943b:96; Mason, 1953:336; 

Dawson, 1959a:20; 1960b:57; Dawson et al., 1960b:16; Dawson, 

1961b:417; Dawson et al., 1964:44, pl. 33: fig. A; Dawson, 1965:27; 

Hollenberg and Abbott, 1966:61; Johansen, 1976a:399, fig. 346; 

Sánchez-Rodríguez et al., 1989:42; Dreckmann et al., 1990:30, pl. 4: 

fig. 7; Ramírez and Santelices, 1991:207; Dreckmann, 1991:34; Stewart, 1991:78; Mateo-Cid and Mendoza-González, 1991:19; LeónÁlvarez and González-González, 1993:462; Serviere-Zaragoza et al., 

1993a:484; González-González et al., 1996:224; L. Aguilar-Rosas et 

al., 2000:131; Riosmena-Rodríguez and Woelkerling, 2000:343.

Pneophyllum nicholsii (Setchell et L. R. Mason) P. C. Silva et P. W. Gabrielson in Gabrielson et al., 2004:94; Mateo-Cid and Mendoza-González, 

2009:612, figs. 17–21.

Pneophyllum nicholsii (Setchell et L. R. Mason) Woelkerling ex Mateo-Cid 

and Mendoza-González, 1992:20, comb. invalid.

Pneophyllum nicholsii (Setchell et L. R. Mason) Chamberlain ex Dreckmann, 

1991:34 comb. invalid.; Mendoza-González and Mateo-Cid, 1992:18; 

Stout and Dreckmann, 1993:14; Mateo-Cid et al., 1993:47; LeónÁlvarez and González-González, 1993:462; Serviere-Zaragoza et al., 

1993a:484; Mateo-Cid and Mendoza-González, 1994b:40; MendozaGonzález et al., 1994:106; González-González et al., 1996:405.

Fosliella nicholsii (Setchell et L. R. Mason) G. M. Smith, 1944:225, pl. 50: 

fig. 8; Dawson, 1945d:43.

Lithophyllum pustulatum f. australis sensu Nichols, 1909:356, pl. 10: figs. 4, 

5, pl. 13: figs. 21–24 [non Lithophyllum pustulatum f. australis Foslie, 

1905a:117].

Crusts epiphytic on various algae; pinkish, mostly 30–50(–

100) μm thick (occasionally to 350 μm), initially in surface view 

more or less discoid, later becoming irregular in outline; composed of 4–7 cell layers; often becoming confluent with only margins monostromatic; construction dimerous, attached by a base 

layer (hypothallium) of small cells, 2.0–3.5 μm tall, 3.5–5.0 μm 

in diameter, parallel to host surface. Cells of erect postigenous 

filaments (2nd order, perithallium) 10–12 μm tall, 7.0–8.0 μm 

wide. Epithallium a single layer of cells 1.5–2.0 μm tall, 3.5–4.5 

μm wide. Cell fusions present; secondary pit connection absent. 

Trichocytes solitary and intercalary (Mateo-Cid and MendozaGonzález, 2009). 

Sporangial conceptacles protruding above vegetative surface, up to 200–350 μm outside diameter; hemispherical with a 

flattened top, and a single pore with extending filaments. Tetrasporangial conceptacle chamber, 40–60(–100) μm tall and 170–

215 μm inside diameter; with central columella and pore with 

extending filaments; tetrasporangia zonately divided, 35–45 μm 

tall, 18–20 μm in diameter. Gametangial thalli monoecious, with 

separate carposporangial and spermatangial conceptacles on 

same thallus, each with a single pore with extending filaments. 

Carposporangial conceptacle chamber elongate, 30–40 μm tall, 

185–230 μm in inside diameter; carposporangia about 30 μm 

tall, 22–25 μm in diameter. Spermatangial conceptacle chamber, 

ovoid, 40–45 μm tall and 60–65 μm inside diameter; spermatangial filaments arising from floor of chamber.

Habitat. On various brown algae, such as Padina,

Dictyota, and Dictyopteris, and probably also on red algae and 

seagrasses; intertidal to shallow subtidal.

Distribution. Gulf of California: El Coloradito 

to Bahía San Carlos; Isla Tiburón (Islas de la Cintura); Isla San 

Pedro Nolasco; Bahía Concepción to La Paz; Mazatlán, Sinaloa 

to Jalisco. Eastern Pacific: Del Norte County, northern California, 

to Todos Santos, Baja California Sur; Isla San Gerónimo and Isla 

Cedros (both off Baja California); Colima to Michoacán; Peru.

Type Locality. On Dictyota binghamiae (=Pachydictyon coriaceum), La Jolla, San Diego County, California, USA. 

Spongites Kützing

Spongites Kützing, 1841:30; Woelkerling, 1985a:123; Penrose and Woelkerling, 1992:87; Penrose, 1996c:273.

Melobesia sect. Spongites (Kützing) Decaisne, 1842b:126.

Crustose corallines vary from flattened crusts to warty 

or fruticose thalli to entirely composed of protuberances; may 

be epizoic, attached to substrate or others may be unattached, 

free-living rhodoliths. Crustose parts of thalli are dorsiventrally 

organized and may be monomerous, dimerous, or both; protuberances if present have radially arranged filaments and are 

monomerous. Monomerous portions composed of a core of 

noncoaxial filaments ventrally arranged, and a peripheral area 

where the distal portions of these filaments (or their derivatives) 

curve outward toward the surface. Dimerous portions composed 

of a single basal layer of primigenous filaments usually consisting 

of nonpalisade cells, and many layers of postigenous filaments 

which arise from the dorsal side of cells of the basal primigenous 

filaments. Postigenous filaments (2nd-order filaments, perithallium) generally greater than 10 cells thick and more than 200 μm 

thick. Some cells of adjacent filaments are joined by cell fusions, 

secondary pit connections are absent. Terminal or subepithallial 

meristematic cells produce epithallial cells outward and vegetative cells inward. The epithallium may be up to several cell layers 

thick, the outermost epithallial cells have rounded or flattened 

(not flared) walls. Trichocytes may be absent, or when present, 

may be single at the surface, or in vertical or horizontal rows, or 

in horizontal fields. Trichocytes have not been observed in primigenous filaments (hypothallium). 

Vegetative reproduction by fragmentation has been reported in some. Reproductive conceptacles have a uniporate 

roof. Sporangial conceptacles develop zonate tetrasporangia, or 

sometimes bisporangia, along the chamber floor or peripheral 

to a central columella. Each sporangium is without an apical 

plug. The conceptacle roof is formed by filaments peripheral 

to sporangial initials or by filaments peripheral and interspersed among sporangial initials. The roof pore has elongated 

cells protruding into the pore canal, and can be with or without extended filaments. Gametangial crusts are monoecious or 
NUMBER 96 • 125

dioecious. Carposporangia and spermatangia are developed in 

separate conceptacles. Carposporangial conceptacles contain a 

carposporophyte composed of gonimoblast filaments developing peripherally from a large central fusion cell bearing terminal 

carposporangia. Spermatangial conceptacles contain unbranched 

spermatangial filaments that develop only on the chamber floor.

There are two species of Spongites reported in the northern 

Gulf of California.

KEY TO THE SPECIES OF SPONGITES IN THE NORTHERN GULF OF CALIFORNIA

1a. Surface smooth; reproductive conceptacle chambers less than 200 μm in diameter; thallus construction dimerous; trichocytes absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S. decipiens

1b. Surface more or less smooth to grainy; reproductive conceptacle chambers up to 250 μm in diameter; thallus construction 

monomerous; trichocytes present at thallus surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S. yendoi

Spongites decipiens (Foslie) Y. M. Chamberlain

FIGURE 56

Lithothamnion decipiens Foslie, 1897:20; 1898:7; Woelkerling, 1993:70.

Spongites decipiens (Foslie) Y. M. Chamberlain, 1993:113, figs. 26, 27, 30, 

35, 36, 47–53; Dreckmann, 1990:35; León-Álvarez and GonzálezGonzález, 1993:462; Serviere-Zaragoza et al., 1993a:484; L. AguilarRosas et al., 2000:129, 131; Mateo-Cid et al., 2000:65; Paul-Chávez 

and Riosmena-Rodríguez, 2000:147; Riosmena-Rodríguez and 

Woelkerling, 2000:337; Serviere-Zaragoza et al., 2007:11; Vidal et al., 

2008:176, tbl. 1; Bernecker, 2009:CD-Rom p. 60; Fernández-García et 

al., 2011:64.

Lithophyllum decipiens (Foslie) Foslie, 1900f:71; 1929:33, pl. 53: fig. 14; 

Dawson, 1944a:270, pl. 57: fig. 20; Mason, 1953 [in part, only southern California specimens]:338, pl. 40 (isotype); Dawson, 1957a:5; 

1960b:37 [in part], pl. 26: figs. 1, 2, pl. 27: figs. 1–3; Dawson et al., 

1960a:16; Dawson, 1961a:416; 1966a:19; Adey and Lebednik, 

1967:16; Masaki, 1968:33, pl. 19, pl. 21: figs. 1–5, pl. 57: figs. 6–8; 

pl. 58; Smith, 1969 [in part, only southern California specimens]:672; 

Huerta-Múzquiz and Garza-Barrientos, 1975:8; Dreckmann, 1991:33;

Woelkerling, 1993:70; González-González et al., 1996:237, 401; AnayaReyna and Riosmena-Rodríguez, 1996:864, tbl. 1; Rodríguez-Morales 

and Siqueiros-Beltrones, 1999:23; Pacheco-Ruíz et al., 2008:208.

Hydrolithon decipiens (Foslie) W. H. Adey, 1970:11; Johansen, 1976a [in 

part, only southern California specimens]:399, fig. 347; Littler and 

Littler, 1981:153; 1984:22; Stewart, 1991:78; Dreckmann, 1991:34; 

Mateo-Cid and Mendoza-González, 1991:20; Mendoza-González and 

Mateo-Cid, 1992:18; Mateo-Cid and Mendoza-González, 1992:20; 

León-Álvarez and González-González, 1993:461; Mateo-Cid et al., 

1993:46; Mendoza-González and Mateo-Cid, 1994:51; MendozaGonzález et al., 1994:106; González-González et al., 1996:226, 397; 

Riosmena-Rodríguez et al., 1998:26; Cruz-Ayala et al., 2001:191; 

CONANP, 2002:139.

Pseudolithophyllum decipiens (Foslie) Steneck et R. T. Paine, 1986:237; 

Pacheco-Ruíz and Zertuche-González, 2002:467.

Crusts thin, (120–)150–240(–300) μm thick, with a relatively smooth surface without protuberances; attached directly 

to substratum. Construction dimerous with a single basal layer 

(hypothallium) of slightly elongated cells 6–10(–15) μm long by 

6–10 μm in diameter. Erect second-order filaments (perithallium) 

form the major portion of thallus thickness; of relatively squarish cells, 5–11 μm tall by 6–10 μm wide. Cell fusions common, 

secondary pit connections absent. Epithallium usually a single 

layer; upper surface of rounded and relatively thick-walled epithallial cells, 1–2 μm tall by 4 μm wide. Trichocytes absent.

Reproductive conceptacles small, mostly less than 200 μm 

outside diameter, with a single pore opening; roof usually white, 

more or less conspicuous against the crust. Sporangial conceptacles 50–100 μm tall, 100–175 μm inside diameter; tetrasporangia develop around chamber periphery. Carposporangial 

conceptacles 80–100 μm inside diameter. Spermatangial conceptacles 40–50 μm tall by 100–175 μm inside diameter. 

Habitat. On rocks, small stones, mollusk shells, 

shell fragments, and other hard surfaces and in tide pools; intertidal to shallow subtidal, probably down to 14 m depths (Dawson, 1960b).

Distribution. Gulf of California: Puerto Peñasco 

to Cabo San Lucas; Isla Ángel de la Guarda; Mazatlán; Sinaloa 

to Jalisco; Islas Marías (Islas Tres Marías). Eastern Pacific: southern California to Bahía Magdalena, Baja California Sur; Isla 

Socorro and Isla San Benedicto (Islas Revillagigedo); Jalisco to 

Oaxaca; Costa Rica; Panama; Colombia. Western Pacific: Japan.

Type Locality. On small stone; San Pedro, Los Angeles County, southern California, USA.

Remarks. Spongites decipiens had been reported in 

the markedly differing seawater temperatures of the boreal to 

cold temperate Pacific coast of British Columbia to Washington 

(e.g., Johansen, 1976a, as Hydrolithon decipiens), in the northern Gulf of California (Dawson, 1944a, 1966b), and the warm 

waters of the southern California (type locality). Steneck and 

Paine (1986, as Pseudolithophyllum decipiens (Foslie) Steneck et 

R. T. Paine) showed that specimens from the boreal northeastern 

Pacific were incorrectly identified, referred them to P. whidbeyense (Foslie) Steneck et R. T. Paine (1986; basionym: Lithophyllum whidbeyense Foslie, 1906a), and restricted the distribution 

of Spongites decipiens to those from southern California and 

Japan. This suggests there may be others mistakenly referred to 

S. decipiens. For the time being, those in the northern Gulf are 

tentatively referred to S. decipiens.

Although Gulf of California specimens can sometimes seem 

similar in the field, generally they can be separated on surface 

texture differences. Spongites decipiens has smooth surfaces and 

S. yendoi has less smooth to grainy surfaces. Internally S. decipiens is dimerous, has conceptales less than 200 μm in diameter, 

and lacks trichocytes, whereas S. yendoi is monomerous, has 
126 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

trichocytes, and usually has larger conceptacle chambers. The 

Gulf specimens need further study and molecular testing with 

types of each of these species to evaluate their taxonomic status 

and phylogenetic relationship.

Spongites yendoi (Foslie) Y. M. Chamberlain

Goniolithon yendoi Foslie, 1900a:25; 1904: pl. 11, fig. 1; Woelkerling, 

1993:238.

Spongites yendoi (Foslie) Y. M. Chamberlain, 1993:102, figs. 2–25, 34; Keats 

et al., 1993:143, figs. 4–23; Penrose, 1996c:280; Yoshida, 1998:615; L. 

Aguilar-Rosas et al., 2000:131; Fragoso and Rodríguez, 2002:127, fig. 

35; Mateo-Cid et al., 2006:56; Vidal et al., 2008:176, tbl. 1.

Lithophyllum yendoi (Foslie) Foslie, 1900a:20; 1929:pl. 53: fig. 16.

Lithothamnion yendoi (Foslie) Me. Lemoine, 1965:10.

Pseudolithophyllum yendoi (Foslie) W. H. Adey, 1970:14.

Lithophyllum decipiens sensu Dawson, 1944a:270 [in part]; 1960b:37 [in 

part; non Lithophyllum decipiens Foslie, 1897:20, which is now Spongites decipiens (Foslie) Y. M. Chamberlain, 1993:107, 113].

Crusts initially more or less discoid, later spreading to more 

than 2 cm; individuals of 3–4 cell layers, 200–500 μm thick; 

may overgrow each other, becoming up to 0.5 mm thick; surface smooth, or become irregular and grainy; firmly adherent to 

substratum. Construction monomerous, with a single system of 

continuously branched filaments that forms a ventral core parallel to the substrate, and then these filaments or their derivatives 

curve outward toward the thallus surface, forming the peripheral 

region. Cells of filaments oblong, 5–22 μm long, 2–6 μm in diameter. Epithallial cell terminating filaments at thallus surface. 

Cell fusions present between adjacent filaments, secondary pit 

connections absent. Trichocytes at dorsal surface, single or in 

horizontal fields.

Sporangia conceptacles more or less even with crust surface, mostly up to 250 μm outside diameter; chambers 80–85 

μm tall, 175–180 μm inside diameter; roof of 3–5 cells with a 

pore canal lined with elongated cells that protrude into pore 

canal but do not extend above pore opening; tetrasporangia 

FIGURE 56. Spongites decipiens: A. Habit (EYD-10967, AHFH, now UC). B. Crust covering rough surface of rock (JN-3839, US Alg. Coll.). 

C. Transection of decalcified crust (JN-3932, US Alg. Coll.). D. Surface detail of crust (JN-3504, US Alg. Coll.).
NUMBER 96 • 127

zonately divided (after Penrose, 1996c). Gametangial thalli unknown in northern Gulf.

Habitat. On rocks or shells or epizoic on mollusks, 

such as Fissurella; intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas. Eastern Pacific: Islas Los Coronados (off northern 

Baja California) to Isla Margarita, Bahía Magdalena (Baja California Sur); Guerrero. Western Pacific: Japan.

Lectotype Locality. Shimoda, Shizuoka Prefecture, southern Japan.

Remarks. The presence of Spongites yendoi , a tropical to subtropical species, is based on its report in the northern 

Gulf from Puerto Peñasco (Mateo-Cid et al., 2006). Chamberlain (1993) referred some of the earlier Mexican specimens of 

Dawson (1960b:38, as “Lithophyllum decipiens”) to Spongites 

yendoi. Upon reexamining some of the same Mexican specimens 

of Dawson (1960b), Fragoso and Rodríguez (2002) found that 

some were species of Hydrolithon, but none of those they examined were Spongites. Thus the presence and distribution of 

S. yendoi the northern Gulf requires further study. 

Uncertain Record:

Spongites fruticulosa Kützing

Spongites fruticulosa Kützing, 1841:33; Woelkerling, 1985a:123, figs. 23–

32; Penrose, 1991:438, figs. 1–3; 1996c:277, fig. 126.

Lithothamnion fruticulosum (Kützing) Foslie, 1895a:46; Dawson, 1960b: 

14 [in part, southern Gulf of California specimens only], pl. 4: figs. 

21–25.

Remarks. Spongites fruticulosa, a rhodolith described from the Mediterranean Sea (Woelkerling, 1993; Basso 

and Rodondi, 2006), is the lectotype species of the genus 

(Woelkerling, 1985a). It has been reported in the southern 

Gulf from Isla Carmén and Punta Los Frailes (Dawson, 1960b, 

1961b, as “Lithothamnion fruticulosum”). However, the presence of S. fruticulosa in the Gulf needs to be verified since the 

“L. fruticulosum” specimens of Dawson (1960b) were later 

identified to be Mesophyllum crassiusculum (Foslie) Lebednik 

(in Athanasiadis et al., 2004) by Johansen (1976a, as L. crassiusculum (Foslie) L. R. Mason, in Setchell and Mason, 1943b). If 

that is correct and no other records are found, it would exclude 

S. fruticulosa from the Gulf of California.

Corallinaceae subfam. Neogoniolithoideae

Corallinaceae subfam. Neogoniolithoideae A. Kato et M. Baba, in Kato, 

Baba and Suda, 2011:669.

Calcified crusts and rhodoliths have lateral cell fusions joining cells of contiguous filaments. Secondary pit connections are 

absent, and the basal layer is without palisade cells. Trichocytes 

may be present or absent, but if present, not in tightly packed 

horizontal fields. Sporangial conceptacles are produced by filaments peripheral to the fertile area. Spermatangial filaments develop from both the floor and roof of spermatangial conceptacle 

chambers.

A recently described monotypic subfamily, C. subfam. Neogoniolithoideae is represented by its single genus in the northern 

Gulf of California.

Neogoniolithon Setchell et L. R. Mason

Neogoniolithon Setchell et L. R. Mason, 1943a:92; Johansen, 1976b: tbl. 2, 

figs. 9, 10, 32; Penrose, 1992:339, figs. 1–29.

Calcified crusts vary from flattened crusts to fruticose 

thalli with protuberances, attached directly to substratum (lack 

haustoria) or may grow as free living, unattached rhodoliths. 

Crustose portions are dorsiventrally organized, constructed of 

a single system of continuously branching filaments (monomerous), with a ventral core of coaxial or noncoaxial filaments (see 

Kato et al., 2013: figs. 16, 17), which curve outward toward 

the thallus surface, forming a wide region. Protuberances, when 

present, have filaments that are radially arranged, with a central core of filaments that curve outward. Each vegetative filament has a terminal or subterminal meristematic cell that divides 

to produce epithallial cells outward to the thallus surface and 

additional vegetative cells inward. Some cells of adjacent filaments are linked by lateral cell fusions, and without secondary 

pit connections. Epithallial cells are rounded or flattened (not 

flared). Trichocytes are intercalary or terminal, may occur singly, 

in vertical rows, or in horizontal fields, but not in large or tightly 

packed horizontal fields.

Vegetative reproduction presumably occurs by fragmentation. Reproductive cells develop within conspicuously protruding, uniporate conceptacles. Sporangial conceptacles are borne 

on separate crusts from the gametophytic crusts. The sporangial 

chamber roof is developed by filaments either surrounding or 

interspersed among sporangial initials, and several cells thick (up 

to 25 cells thick), with a single, prominent pore lined with cells 

laterally extending into the pore canal. Zonate tetrasporangia or 

bisporangial are produced along the chamber floor and walls, 

either without a columella or, if present, develop peripheral to 

central columella. Each sporangium is without an apical plug. 

Gametophytes are monoecious or dioecious, with carposporangia and spermatangia usually in separate conceptacles (rarely 

within the same conceptacle). Carposporophytes have terminal 

carposporangia borne on short gonimoblast filaments that arise 

from the dorsal surface of a thin, flattened fusion cell on the 

chamber floor (cf. Masaki, 1968; Penrose, 1992). Unbranched 

spermatangial filaments develop from the floor, walls and roof of 

the male conceptacle chamber (Penrose, 1992).

Remarks. There is one species recognized in the 

southern Gulf of California: Neogoniolithon setchellii (Foslie) W. 

H. Adey (1970; basionym: Lithothamnion setchellii Foslie, 1897; 

=Hydrolithon setchellii (Foslie) Setchell et L. R. Mason, 1943a), 

reported from Punta Arena to Cabo Pulmo (Mateo-Cid et al., 

2000; Cruz-Ayala et al., 2001), Mazatlán (Mendoza-González et 

al., 1994), Bahía de Banderas (Serviere-Zaragoza et al., 1993a), 

Nayarit (Mateo-Cid and Mendoza-Gonzalez, 1992; León-Álvarez 

and González-González, 1993), and Jalisco (Mendoza-González 
128 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

and Mateo-Cid, 1992), and in Pacific Mexico from Isla Guadalupe (Dawson, 1960b; Stewart and Stewart, 1984).

One species of Neogoniolithon is recorded in the northern 

Gulf of California.

Neogoniolithon trichotomum (Heydrich) Setchell et L. R. Mason

FIGURE 57

Lithothamnion trichotomum Heydrich, 1901b:538; Woelkerling, 1998:364; 

Woelkerling et al., 1998:592, figs. 304–306.

Neogoniolithon trichotomum (Heydrich) Setchell et L. R. Mason, 

1943a:92; Tseng, 1983:82, pl. 44: fig.2; Mendoza-González and 

Mateo-Cid, 1992:18; Mateo-Cid et al., 1993:46; León-Álvarez and 

González-González, 1993:462; Serviere-Zaragoza et al., 1993a:484; 

Mendoza-González and Mateo-Cid, 1994:51; Mendoza-González 

et al., 1994:106; Riosmena-Rodríguez and Paul-Chávez, 1997:71; 

Rodríguez-Morales and Siqueiros-Beltrones, 1999:23; L. Aguilar-Rosas 

et al., 2000:131; Cruz-Ayala et al., 2001:191; Riosmena-Rodríguez and 

Woelkerling, 2000:346; Hinojosa-Arango and Riosmena-Rodríguez, 

2004:110, 118; Mateo-Cid et al., 2006:56; Serviere-Zaragoza et al., 

2007:11; Bernecker, 2009:CD-Rom p. 60; Fernández-García et al., 

2011:62; Kato et al., 2013:18, figs. 3–15, tbl. 2.

Lithophyllum trichotomum (Heydrich) Me. Lemoine, 1929a:45; Dawson, 

1944a:267, pl. 55, fig. 2: pl. 58: figs. 1(lectotype), 4–6, pl. 60; Taylor, 1945:180; Dawson, 1959a:20; 1960b:51, pl. 44, figs. 2, 3, pl. 45: 

figs. 1, 2, pl. 46; 1961b:417; 1966a:19; Huerta-Múzquiz and TiradoLizárraga, 1970:128; Huerta-Múzquiz and Mendoza-González, 

1985:48; Dreckmann, 1991:33; León-Álvarez and González-González, 

1993:462; Serviere-Zaragoza et al., 1993a:484; González-González et 

al., 1996:239, 401; Mateo-Cid et al., 2000:65.

Crustose corallines 100–1000 μm or more thick, ranging from 10–110 cell layers; fruticose, with numerous, slender, 

subcylindrical to compressed protuberances. Initially a small 

encrusting form, later may spread up to 10 cm or more, with 

lobed margins; surface with simple to subdichotomously or trichotomously branched protuberances of more or less uniform 

diameter. Some may become free living rhodoliths, up to 5 cm 

or more in diameter. Protuberances 1.0–1.5 mm in diameter 

and up to 15 mm in length, with rounded or truncated apices; 

FIGURE 57. Neogoniolithon trichotomum: A. Habit (isotype, L. Diguet-1894, UC). B. Habit (EYD-619-40, AHFH, now UC). C. Close-up 

showing surface detail of tips of branches (EYD-1972, AHFH, now UC). D. Longitudinal section through an erect divided fertile branch, with 

empty conceptacle (EYD-226-40, AHFH, now UC).
NUMBER 96 • 129

becoming abundant or densely congested or sometimes anastomosing. Monomerous; crustose portions with a ventral core of 

filaments oriented parallel to the substratum (hypothallium) up 

to 13 cell layers thick, of cells 12–40 μm long, about 10–17 μm 

in diameter; upward curved filaments (perithallium) of cells progressively decreasing in size toward thallus surface, 6–25 μm tall 

by 5–17 μm in diameter. Filaments of protuberances of quadrangular cells, 17–40 μm tall by 8–14 μm wide in central portions; 

outward cells smaller, 14–18 μm long, 9–14 μm wide, in fewer, 

less-defined layers. Epithallial cells about 4.5–7 μm tall and 9–12 

μm wide, terminal on each filament at thallus surface, forming a 

single layer above elongated subepithallial cells, 7–20 μm tall by 

8–15 μm wide. Cellular fusions present between some cells of adjacent filaments. Secondary pit connections absent. Trichocytes 

present, scattered and in vertical rows (after Dawson, 1960b; 

and in part Kato et al., 2013).

Reproductive conceptacles conical to dome-shaped, often 

terminal on branch apices. Sporangial conceptacles large, about 

350 μm in length, usually single and terminal on the tips of the 

protuberances; chambers up to 290 μm tall by 450–1000 μm inside diameter, without a central columella; roof with a prominent 

central pore. Zonate tetrasporangia, 30–60(–100) μm tall and 

60–160 μm in diameter; on floor and walls of conceptacle chamber. Gametophytes not known in northern Gulf of California. 

Carposporangial conceptacles with chambers, 120–310 μm tall 

by 310–640 μm inside diameter; gonimoblast filaments arising 

from a flattened fusion cell over the chamber floor, with terminal carposporangia about 25–50 μm in diameter. Spermatangial 

conceptacles with chambers 125–160 μm tall and about 370 

μm inside diameter; unbranched spermatangial filaments along 

floor, walls, and roof of chamber; spermatangial parent cells cut 

off from basal cell of filaments; each spermatangial parent cell 

produces 2–3 spermatangia, 2–3 μm tall by 3–5 μm in diameter 

(gametophytes descriptions after Kato et al., 2013).

Habitat. On rocks, shells, or corals; in sand-covered 

tidal crevices and in tide pools; or as free-living rhodoliths; intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabo Pulmo; Mazatlán, Sinaloa to Jalisco; Isla María Magdalena (Islas Marías). Eastern Pacific: Isla Clarión and Isla Socorro 

(Islas Revillagigedo); Baja California; Jalisco to Oaxaca; Costa 

Rica; Panama. Western Pacific: China (Zhang and Zhou, 1980); 

Vietnam; Japan.

Type Locality. Near La Paz, Baja California Sur, 

Gulf of California, Mexico (Heydrich, 1901b; Woelkerling, 

1998).

Remarks. Described from the southern Gulf of 

California, Neogoniolithon trichotomum is relatively common 

throughout the Gulf. In the field it is distinguished from other 

Gulf crustose corallines by its characteristic slender, mostly subcylindrical protuberances and the large terminal conceptacles of 

up to 450–1000 μm inside diameter. Although N. trichotomum 

can sometimes resemble some Lithophyllum pallescens, microscope examination will distinguish L. pallescens by its secondary 

pit connections linking adjacent cells of the perithallial filaments 

(cell fusions absent) and much smaller sporangial conceptacles 

less than 400 μm inside diameter.

Corallinaceae subfam. Porolithoideae

Corallinaceae subfam. Porolithoideae A. Kato et M. Baba, in Kato, Baba and 

Suda, 2011:669.

Calcified crusts have lateral cell fusions between some cells 

of adjacent filaments. Trichocytes are present in large, tightly 

packed horizontal fields. Secondary pit connections are absent, 

and the basal layer is composed of nonpalisade cells. Sporangial 

conceptacles are produced by filaments peripheral to the fertile 

area and interspersed among tetrasporangial initials. Spermatangial filaments develop on the chamber floor of the spermatangial 

conceptacle. 

The C. subfam. Porolithoideae is represented by Porolithon

in the Gulf of California.

Porolithon Foslie

Porolithon Foslie, 1909:57; Kato et al., 2011:669; Bittner et al., 2011:710.

Crusts usually found growing on rocks, shells, or other 

hard surfaces. Anatomically, thalli are primarily monomerous in 

construction. The hypothallium is up to several cell layers thick, 

composed of a noncoaxial core of filaments parallel to the substrate. The perithallium is multilayered, consisting of the continuation of the core filaments and their branches as they curve 

upward toward the dorsal thallus surface. Lateral cell fusions are 

present between some cells of adjacent filaments, and secondary 

pit connections are absent. Trichocytes are present in large, horizontal, postulate (=pustulous of Adey, 1970) fields without any 

filaments between the individual trichocytes. The epithallium is 

of 1–3 cell layers.

Sporangial conceptacles formed by filaments peripheral to 

the fertile area and interspersed among the sporangial initials, 

conceptacles open by a single pore. Spermatangial filaments develop from the floor of the male conceptacle chamber.

Remarks. Penrose and Woelkerling (1992) considered the generitype, Porolithon onkodes (Heydrich) Foslie 

(1909), to be congeneric with Hydrolithon, as H. onkodes (Heydrich) D. Penrose et Woelkerling (1992). If this is followed, then 

the other taxa placed in Porolithon, including the Gulf of California P. sonorense, would need to have their generic placement 

clarified.

On the basis of their morphological and molecular analyses 

Porolithon has been resurrected by Kato et al. (2011). Bittner et 

al. (2011) restricted Porolithon to include members that were 

primarily monomerous in construction and with trichocytes in 

large, horizontal, postulate fields that lack any vegetative filaments between the individual trichocytes. Kato et al. (2011) studied Japanese specimens of P. onkodes, and Bittner et al. (2011) 

studied specimens from New Caledonia. In order to corroborate 

their conclusions, morphological and molecular studies need to 
130 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

be undertaken on the type and topotype material of P. onkodes

(type locality: Tami Island, Gulf of Huon, Papua New Guinea). 

Bittner et al. (2011) also suggested, along with several other taxa, 

that Hydrolithon samoënse should be referred to Porolithon. 

Woelkerling et al. (2012) did not accept them as distinct genera, 

noting that the “Hydrolithon–Porolithon complex,” needs more 

morphological, anatomical and molecular analyses to resolve 

their taxonomic status.

Two species of Porolithon are present in the northern Gulf 

of California.

KEY TO THE SPECIES OF POROLITHON IN THE NORTHERN GULF OF CALIFORNIA

1a. Crust surface of undulate or wavy to convoluted raised ridges (up to 1 cm high), plate-like crusts with distinct rounded, 

lighter-colored margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. sonorense

1b. Crust surface relatively smooth; later expanding and overlapping, surface becoming somewhat warty or lumpy . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. onkodes

Porolithon onkodes (Heydrich) Foslie

Lithothamnion onkodes Heydrich, 1897a:6, pl. 1: fig. 11a, b; 1897c:410 [as 

“L. oncodes”]; Woelkerling, 1993:164; 1998:357; Woelkerling et al., 

1998:575–576, figs. 287–288. 

Porolithon onkodes (Heydrich) Foslie, 1909:57; Taylor, 1950:125, pl. 9, 

pl. 61: figs. 1–2, pl. 62: figs. 1–2, pl. 63: figs. 1–2; Lemoine, 1966:10, 

figs. 5–6, pl. 1: figs. B–D; Dawson, 1959d:4; 1960a:43; 1961b:415; 

Adey and Lebednik, 1967:46; Littler, 1971:92; Adey et al., 1982:7, 

figs. 2–4; Tseng, 1983:82, pl. 3: fig. 2, pl. 44: fig. 4; Santelices and Abbott, 1987:8; Ramírez and Santelices, 1991:223; León-Álvarez and 

González-González, 1993:462; González-González et al., 1996:257; 

Kato et al., 2011:669.

Hydrolithon onkodes (Heydrich) D. Penrose et Woelkerling, 1992:83, figs. 

4, 5; Penrose, 1996a:261, fig. 119A–D; Keats et al., 1997b:281, figs. 

7–10; Yoshida, 1998:561, fig. 3-22(A–D); Fragoso and Rodríguez, 

2002:120, figs. 22–24; Mateo-Cid et al., 2006:56; Mendoza-González 

et al., 2009:225, figs. 4–5; Bernecker, 2009:CD-Rom p. 59; FernándezGarcía et al., 2011:62.

Goniolithon onkodes (Heydrich) Foslie, 1898:8; 1899:5.

Lithophyllum onkodes(Heydrich) Foslie, 1900c:8; 1909:38; 1929:36, pl. 67: 

figs. 3–4, 6–7.

Lithophyllum onkodes (Heydrich) Heydrich, 1901b:533.

Spongites onkodes (Heydrich) D. Penrose et Woelkerling, 1988:159, 173, tbl. 

2, figs. 10–14; Dreckmann, 1991:35.

Crusts pink to yellowish pink, initially subspherical, later 

expanding and overgrowing layers; surface somewhat flat to 

warty or lumpy, rough appearance due to abundant trichocyte 

fields (groups); variable in thickness, (105–)200–950 μm (in Gulf 

mostly less than 1.0 mm thick) as reported elsewhere from a 

few millimeters thick (Mendoza-González et al., 2009) and up 

to several centimeters thick (Adey et al., 1982). Epithallium of 

1–2(–3) cell layers; composed of rounded cells, 2–6 μm tall and 

5–9 μm in diameter. Intercalary meristematic cells below epithallium, of cells 4–11 μm long, 4–8 μm in diameter. Perithallium 

multilayered, of cells 4–13 μm long and 4–10 μm in diameter; 

cell fusions abundant. Trichocytes 10–30 μm long and 4–15 μm 

in diameter; forming compact linear fields (groups) of 4–12 cells, 

up to 100 μm in diameter throughout perithallium. Hypothallium multilayered, 50–150(–350) μm thick; of cells 11–24 μm 

long and 5–14 μm in diameter.

Reproductive conceptacles usually slightly raised above 

surface; conceptacle roofs of 3–6 cell layers; uniporate. Tetrasporangial conceptacles scattered; 110–230 μm inside diameter; 

tetrasporangia zonately divided, 50–75 μm long, 20–40 μm in 

diameter. Cystocarpic conceptacles 150–210 μm inside diameter; 

carposporangia 35–70 μm long, 25–70 μm in diameter. Spermatangial conceptacles 130–210 μm inside diameter; spermatia 

elongated to ellipsoidal, 3–5 μm long, 1–2 μm in diameter. 

Habitat. On rocks and shells and other hard substratum; intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco. 

Eastern Pacific: southern California; Guerrero to Chiapas; Clipperton Island; Costa Rica; Rapa Nui (Easter Island; Isla de Pascua). Central Pacific: Hawaiian Islands. Western Pacific: China; 

Japan; Papua New Guinea.

Type Locality. Tami Island, northwest side of Gulf 

of Huon, Papua New Guinea.

Remarks. The generitype of Porolithon is Lithothamnion onkodes. Porolithon onkodes was reported in the upper Gulf 

from Puerto Peñasco by Mateo-Cid et al. (2006); as I have not 

seen their material, the description for the species is based in part 

on Adey et al. (1982) and Mendoza-González et al. (2009).

Porolithon sonorense E. Y. Dawson

FIGURES 8F, 58

Porolithon sonorense E. Y. Dawson, 1944a:273 [as “P. sonorensis”], pl. 

57: figs. 17–19, pl. 61: fig. 2; 1960b:25, pl. 15: figs. 1, 2, pl. 16: fig. 

1; 1961b:415; 1966a:19; Littler and Littler, 1981:153; Johansen, 

1981:2, fig. 2D; Littler and Littler, 1984:27; Anderson, 1991:35; 

Dreckmann, 1991:35 [as “Spongites sonorensis”]; González-González 

et al., 1996:257; Riosmena-Rodríguez and Paul-Chávez, 1997:71; 

Rodríguez-Morales and Siqueiros-Beltrones, 1999:23; L. Aguilar-Rosas 

et al., 2000:131; Riosmena-Rodríguez and Woelkerling, 2000:345; 

Cruz-Ayala et al., 2001:191; CONANP, 2002;139; Pacheco-Ruíz and 

Zertuche-González, 2002:467.

Crusts forming plate-like lobes, loosely attached, with a tendency to overgrow each other and to form upraised, undulate or 

wavy ridges where they meet, becoming convoluted, up to 1 cm 

high. Individual crusts 150–200 μm thick, with distinct rounded, 

light-colored margins. Hypothallium, where evident, 8–10 cell 

layers thick; cells 18–26 μm long by 9–14 μm wide. Perithallium of squarish cells, 6–9 μm long by 6–7 μm wide. Epithallium of 2–4 layers of flattened cells, 4–5 μm tall by 6 μm wide. 

Trichocytes 20–25 μm long by 9–12 μm wide, grouped together 
NUMBER 96 • 131

in horizontal rows of 6–7 cells; sometimes visible near the surface, or deep within the perithallium.

Tetrasporangial conceptacles immersed or slightly protruding, and scattered over surface, 175–250 μm in diameter, with 

a single pore opening; tetrasporangia 60 μm in length or more. 

Gametangial thalli not yet reported.

Habitat. Usually common where found; loosely attached to hard surfaces; mid to low intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de La Paz. Eastern Pacific: Bahía Sebastián Vizcaíno, 

Baja California.

Type Locality. On rocky shore; west side of Puerto 

Refugio, Isla Ángel de la Guarda (Islas de la Cintura), Gulf of 

California, Mexico.

Remarks. Porolithon sonorense is recognized in the 

field by its upraised, undulate or wavy to convoluted ridges (up 

to 1 cm high), with distinct rounded, lighter-colored margins 

(Figure 58C, D). Of the known species of Porolithon, P. sonorense is a relatively thin crust in comparison to other members 

of the genus, which includes the massive species that occur in 

exposed reef fronts of the central Pacific (Adey et al., 1982).

Hapalidiaceae

Hapalidiaceae J. E. Gray, 1865 [1864]:22; Harvey et al., 2003a:995.

The Hapalidiaceae include taxa of the Corallinales whose 

tetrasporangia produce zonately arranged spores and whose tetrasporangia and/or bisporangia are borne in conceptacles with a 

multiporate plate. Each sporangium produces an apical plug at 

the multiporate plate.

Remarks. Doweld (2012) proposed the name Melobesiaceae Früh (1891) for conservation over Hapalidiaceae J. E. Gray 

(1865) and Lithothamniaceae H. J. Haas (1886, as ‘Lithothamnieae’; fide Doweld, 2012:680). Herein Hapalidiaceae J. E. Gray is 

FIGURE 58. Porolithon sonorense: A, B. Habits of type collection (EYD-226a-40, AHFH-25, now UC). C. Detail of crusts, showing adjacent 

undulating plates abutting each other (JN-3775, US Alg. Coll.). D. Close up of erect, outer edges of abutting undulate plates (EYD-984, AHFH, 

now UC).
132 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

used, following Harvey et al. (2003a), until the proposal has been 

considered by the International Botanical Nomenclature Committee. 

There are two subfamilies of the Hapalidiaceae represented 

in the northern Gulf of California.

KEY TO THE SUBFAMILIES OF THE HAPALIDIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Thallus without cell fusions and without secondary pit connections between cells of adjacent filaments; sporangial conceptacles with multiporate plate that is acellular at maturity, composed of a calcium carbonate matrix recessed below a 

single pore opening . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. subfam. Choreonematoideae

1b. Thallus with cell fusions adjoining some cells of adjacent vegetative filaments, secondary pit connections absent; sporangial conceptacle roof with a multiporate plate that is cellular at maturity . . . . . . . . . . . . . . H. subfam. Melobesioideae

Hapalidiaceae subfam. Choreonematoideae

Hapalidiaceae subfam. Choreonematoideae Woelkerling, 1987a:125; Harvey et al., 2003a:994.

The subfamily Choreonematoideae is characterized by nongeniculate thalli; without cell fusions and without secondary pit 

connections between cells of vegetative filaments; conceptacle roof 

and walls composed of a single cell layer; presence of an apical 

plug terminal on each tetrasporangium or bisporangium. Sporangial conceptacle roof with an inner multiporate plate, composed 

only of a calcium carbonate matrix (acellular) at maturity, recessed 

below a single pore opening. Spermatangial filaments developed on 

the floor, walls, and roof of the spermatangial conceptacles.

Remarks. The Choreonematoideae includes a single 

genus and species, Choreonema thuretii, known to occur on the articulated coralline genera Jania, Haliptilon, and Cheilosporum, all 

members of Corallinaceae subfam. Corallinoideae tribus Janieae 

(Johansen, 1981). Choreonema has also been reported on Corallina (Setchell and Gardner, 1930) and Amphiroa (Dawson, 1960b). 

Choreonema F. Schmitz

Choreonema F. Schmitz, 1889:455; Woelkerling, 1987a:122; Broadwater et 

al., 2002:1157.

Endosiphonia Ardissone, 1883:450, nom. illeg. [non Endosiphonia Zanardini, 1878:35].

Minute subspherical conceptacles are the only visible portion of the thallus, whereas the vegetative portions are endophytic within the algal host’s tissue. Reproductive conceptacles 

are lightly calcified and protrude above the intergenicula surface 

of the host articulated coralline. The vegetative portion is filamentous with largely diffuse and unconsolidated, mostly simple 

or branching filaments that penetrate into its host; these filaments become pseudoparenchymatous to consolidated in areas 

of conceptacle production. Lenticular cells on the endophytic 

filaments produce processes (visible only with transmission electron microscope) that become connected to host cells, indicating its parasitism. Epithallial cells are absent from endophytic 

filaments but present on conceptacles. Haustoria and trichocytes 

are lacking. Cells of contiguous filaments are not linked by cell 

fusions or secondary pit connections. 

Reproductive structures develop within the hemispherical to 

spherical, calcified conceptacles on the host. Conceptacles arise 

from groups of noncalcified, endophytic filaments cells to form 

a pseudoparenchymatous patch just below the surface of the 

coralline host. Sporangial conceptacle roofs are composed of a 

single layer of cells produced from the filaments peripheral to the 

sporangial initials. Tetrasporangial initials are developed without 

columella from the chamber floor of their conceptacles. Each tetrasporangium is zonately divided and produces a mucilaginous 

apical plug that blocks its pore in the multiporate plate above 

them; the mucilage of the group of plugs extends outward, obstructing the single outer conceptacle opening prior to sporangia 

release. Carpogonia and spermatangia are produced within separate uniporate conceptacles on different individuals (dioecious). 

Each carpogonial conceptacle contains carpogonia that are terminal on 2–3 celled unbranched filaments arising from the chamber 

floor. Carposporophytes develop after presumed fertilization and, 

when mature, are composed of a central fusion cell and severalcelled filaments that bear terminal carposporangia. Spermatangia are produced on unbranched filaments arising from the floor, 

walls, and roofs of the spermatangial conceptacle chamber. 

Remarks. Choreonema is a monotypic genus. The 

only known species is currently considered to be cosmopolitan. 

Reported in the southern Gulf, it likely occurs in the northern 

Gulf of California as well.

Choreonema thuretii (Bornet) F. Schmitz

Melobesia thuretii Bornet in Thuret et Bornet, 1878:96, pl. 50: figs. 1–8; 

Woelkerling, 1998:381; Woelkerling et al., 1998:629, fig. 341.

Choreonema thuretii (Bornet) F. Schmitz, 1889:455; Suneson, 1937:53, figs. 

33–35, pl. 3: figs. 10–12; Hamel and Lemoine, 1953:110, figs. 74–76, 

pl. 22: fig. 3; Setchell and Gardner, 1930:175; Taylor, 1945:184, pl. 45; 

Hollenberg, 1948:157; Dawson, 1960b:60, pl. 1: figs. 1–3; 1961b:417; 

Johansen, 1976a:397, fig. 344; Cabioch, 1980:707; Johansen, 1981:54: 

fig. 9A,B; Schnetter and Bula-Meyer, 1982:128, pl. 23: fig. B; Stewart 

and Stewart, 1984:143; Woelkerling, 1987a:113, figs. 1–5; 1988:90; 

Dreckmann et al., 1990:30; Ramírez and Santelices, 1991:201; Dreckmann, 1991:35; León-Álvarez and González-González, 1993:461; 

Bula-Meyer, 1995:34; González-González et al., 1996:191, 388; 

Mendoza-González and Mateo-Cid, 1996a:23, figs. 1–7; Broadwater 

and La Pointe, 1997:396, figs. 1–27; Yoshida, 1998:548, fig. 3-18A–F; 

Dreckmann and Gamboa-Contreras, 1998:75; Riosmena-Rodríguez 

and Woelkerling, 2000:346; Broadwater et al., 2002:1157, figs. 1–8; 

Dreckmann et al., 2006:154; Fernández-García et al., 2011:61.

Melobesia deformans Solms-Laubach, 1881:53, 57, pl. 1: fig. 5, pl. 3: figs. 

12, 26; Woelkerling, 1987b:277, figs. 1–7; 1998:371; Woelkerling et 

al., 1998:611, fig. 323.
NUMBER 96 • 133

Minute semi-endophytic parasite on articulated corallines; 

reproductive conceptacles, subspherical lightly calcified, external 

to host (only visible portion of the thallus). Thallus construction 

mostly diffuse, with pseudoparenchymatous areas that produce the 

conceptacles. Endophytic, noncalcified, filaments of elongated cells, 

unconsolidated, and simple or branched; endophytic filaments penetrate tissue of the algal host with lenticular cells and processes 

(only seen with TEM) connecting its cells to host cells; supporting 

its probable parasitism. Filaments lack cell fusions or secondary pit 

connections; cells multinucleate and without mature plastids.

Reproductive conceptacles (seen with SEM) have a reticulate 

surface pattern of calcified ridges above a layer of calcified plates 

(see Broadwater et al., 2002: fig. 2a–f ). Sporangial conceptacles 

(50–)75–100 μm tall and 90–120 μm outside diameter; chamber 

about 75 μm inside diameter, walls about 13 μm thick; exit pore in 

outermost region of the conceptacle is a single opening, but inside 

the opening is a slightly recessed, inner multipore plate with about 

15–30 sieve-like openings (see Broadwater et al., 2002: figs. 2f, 

3a–c). Tetrasporangia zonately divided, 45–55 μm long, 18–22 μm 

in diameter, along conceptacle floor, each with terminal mucilaginous plug at the multiporate plate. Gametangial thalli dioecious. 

Carposporangial conceptacles 105–120 μm tall, 105–126 μm 

outside diameter; inside chambers about 60 μm tall, 56 μm inside 

diameter, walls about 30 μm thick; with central fusion cell and 

gonimoblast filaments consisting of several cells, cells progressively 

larger upward to terminal carposporangium. Spermatangial conceptacles, 96–135 μm tall, about 100–125 μm outside diameter; 

inside chamber flask shaped, about 45 μm tall, about 60–70 μm 

wide, with roof about 20 μm thick; spermatia spherical to ovoid, 

in chain-like rows (reproductive characters after Chamberlain and 

Irvine, 1994a; Mendoza-González and Mateo-Cid, 1996a).

Habitat. Semi-endophytic parasite on species of 

Corallina, Jania, and Amphiroa; intertidal.

Distribution. Gulf of California: Bahía Agua 

Verde to Cabeza Ballena. Eastern Pacific: Santa Catalina Island 

and San Clemente Island (California Channel Islands); Corona 

del Mar (Newport Beach) to La Jolla (southern California); Isla 

Guadalupe; Punta Santa Rosaliita (Baja California) to Punta 

Malarrimo, Bahía Sebastián Vizcaíno (Baja California Sur); Isla 

Socorro (Islas Revillagigedo); Colima to Oaxaca; Costa Rica; 

Isla de Gorgona, Colombia; Galapágos Islands; Chile; Rapa Nui 

(Easter Island; Isla de Pascua). Western Pacific: Japan.

Type Locality. On the coralline Haliptilon squamatum (Linnaeus) H. W. Johansen, L. M. Irvine et A. Webster; Pointe 

de Querqueville, WNW of Cherbourg, Normandy, Atlantic France.

Hapalidiaceae subfam. Melobesioideae

Corallinaceae subfam. Melobesioideae Bizzozero, 1885:109.

Hapalidiaceae subfam. Melobesioideae (Bizzozero) A. S. Harvey, Broadwater, Woelkerling et Mitrovski, 2003a:995; Harvey et al., 2003b: 

648, 652.

Corallinaceae subfam. Lithothamnioideae Foslie, 1908:19.

The subfamily Melobesioideae is characterized by nongeniculate thalli; some cells of adjacent vegetative filaments adjoined 

by cell fusions; lack of secondary pit connections; and sporangial 

conceptacle roofs with multiporate plate composed of cells at 

maturity. Sporangial conceptacles with tetrasporangia (zonately 

divided) or bisporangia, underneath the multiporate plate, each 

sporangium has a terminal apical plug below its outer pore in 

the conceptacle roof. Carpogonial and spermatangial conceptacles are uniporate. Spermatangia are developed on unbranched 

or branched filaments issued from the chamber floor, walls, and 

roof of the spermatangial conceptacles.

The Hapalidiaceae subfam. Melobesioideae is represented 

by three genera in the Gulf of California.

KEY TO THE GENERA OF HAPALIDIACEAE SUBFAM. MELOBESIOIDEAE 

IN THE NORTHERN GULF OF CALIFORNIA

1a. Thin, lightly calcified crusts, usually epiphytic; thallus construction dimerous, consisting of 2 distinct groups of filaments: a 

lowermost hypothallium of a monostromatic layer of palisade or nonpalisade cells and second order of filaments forming 

the perithallium or epithallium arising more or less perpendicular from the cells of the lowermost layer . . . . . . Melobesia

1b. Thallus construction monomerous, consisting of a single system of branching filaments that form a ventral or central core 

and a peripheral region where portions of the core filaments curve outward toward the thallus surface; crusts growing on 

rocks or as unattached nodules (rhodoliths) or epiphytic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Crusts on rocks or epiphytic on articulated corallines; with margins free; may be rhodoliths in other places; thallus contains a ventral and/or central core of coaxial filaments; in vertical section outermost cell walls of terminal epithallial cells

rounded or flattened but not flared . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mesophyllum

2b. Crusts with different surfaces: some smooth; others with extended protuberances; firmly attached to hard substratum 

or free-living, unattached nodules (rhodoliths); hypothallium of noncoaxial filaments; in vertical section, outermost cell 

walls of terminal epithallial cells normally flattened and flared . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lithothamnion

Lithothamnion Heydrich

Lithothamnion Heydrich, 1897c:412, nom. cons.

Lithothamnium Philippi, 1837:387, nom. rej. [see Woelkerling, 1985b:303, 

1988:169].

Thalli are crustose and spreading, with an upper surface 

that may be smooth to irregular or may be entirely composed 

of simple to branched protuberances, often short, wart-like, 

knobby, or stubby. Many are firmly attached to hard substratum, such as rocks, shells, or other hard surfaces. Some species 
134 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

become unattached and form irregularly shaped, free-living nodules (rhodoliths). All are pseudoparenchymatous in structure, 

with a dorsiventral organization in crustose portions, and radially arranged in the protuberances. Thalli are monomerous; 

internally composed of branching, laterally adjoined filaments, 

noncoaxial, in lower (ventral) core or central core, and then filaments outwardly curving toward the thallus surface, forming a 

peripheral area (perithallium), with filaments terminating with 

epithallial cells. Some cells of filaments are joined by cell fusions; 

secondary pit connections are absent; and trichocytes are absent 

in most species, occasional in some. Epithallium a unistratose 

layer of cells that are distinctively angular in vertical section; outermost walls of terminal epithallial cells are uniquely flattened 

and flared (see Woelkerling, 1988: fig. 192). 

Assumed vegetative reproduction is apparently by fragmentation. Sporangial conceptacles, multiporate and without columella, develop zonately divided tetrasporangia or bisporangia 

on the chamber floor. Each tetrasporangium or bisporangium 

produces an apical plug that blocks its roof pore prior to spore 

release. The conceptacle roof is formed by thick-walled apices 

of sporangial filaments that are interspersed among the sporangia but do not persist among sporangia. Gametangial thalli may 

be dioecious or monoecious, with carpogonia and spermatangia 

developed in separate uniporate conceptacles. Carpogonia terminate 2- to 3-celled filaments that develop from the conceptacle 

chamber floor. Carposporophytes are composed of short, gonimoblast filaments that bear terminal carposporangia and lack a 

conspicuous fusion cell. Roofs of spermatangial and carposporangial conceptacles are formed by overgrowth of surrounding 

tissue. Spermatangia filaments may be unbranched or branched 

and bear spermatia in clusters and arise from the conceptacle 

floor, sides, and roof. 

Currently, three species of Lithothamnion are known in the 

northern Gulf of California. 

KEY TO THE SPECIES OF LITHOTHAMNION AND MESOPHYLLUM 

IN THE NORTHERN GULF OF CALIFORNIA

1a. Crusts relatively thin, up to 200 μm thick; with smooth to slightly irregular surfaces, lacking any protuberances or 

branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lithothamnion microsporum 

1b. Crusts thicker, with protuberances or protuberant branches; encrusting or free-living, unattached rhodoliths . . . . . . . . 2

2a. Crusts or rhodoliths with small, close together protuberances of more or less similar size; hypothallium composed of 

patches of coaxial filaments (arching tiers of laterally aligned cells) . . . . . . . . . . . . . . . . . . Mesophyllum crassiusculum 

2b. Crusts or rhodoliths with protuberances not as above; hypothallium filaments mostly noncoaxial (cells not laterally 

aligned in arching tiers) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Rhodoliths; rounded to irregularly shaped nodules either with short, knobby protuberant branches (2–3 mm in diameter), 

or slender subcylindrical branched protuberances longer than 6 mm, 1–2 mm in diameter . . . . . . Lithothamnion australe

3b. Rhodoliths; rounded, lumpy-shaped nodules, with extending simple or branched warty protuberances, shorter, up to 

6 mm tall; . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lithothamnion muelleri

Lithothamnion australe Foslie

FIGURE 59

Lithothamnion australe Foslie in Weber-van Bosse and Foslie, 1904:24, pl. 

2: fig. 10; Dawson, 1960b:11, pl. 4: figs. 1–20, pl. 5: fig. 2, pl. 47: figs. 

5–10; 1961b:413; Adey and Lebednik, 1967:82; Adey, 1970:19; HuertaMúzquiz and Tirado-Lizárraga, 1970:128; Johansen, 1976a:383, fig. 

322; Huerta-Múzquiz, 1978:340; Adey et al., 1982:53, figs. 37, 39, 40; 

Stewart and Stewart, 1984:143; Ortega et al., 1987:73 [with query], 

pl. 4: fig. 21; Stewart, 1991:78; Dreckmann, 1991:34; Woelkerling, 

1993:34; Serviere-Zaragoza et al., 1993a:484; Mendoza-González and 

Mateo-Cid, 1994:51; González-González et al., 1996:239; Foster et al., 

1997:133; Riosmena-Rodríguez and Paul-Chávez, 1997:71; Woelkerling, 1998:330; Riosmena-Rodríguez and Woelkerling, 2000:334; 

Serviere-Zaragoza et al., 2007:10; Fernández-García et al., 2011:62.

Lithothamnion corallioides f. australis Foslie, 1895b:8, figs. 6, 7.

Lithothamnion australe Foslie,1900e:13, nom. nud.

Lithophyllum australe (Foslie) Me. Lemoine, 1917:131; Chávez-Barrear, 

1972b:269; Huerta-Múzquiz, 1978:340; Huerta-Múzquiz and 

Mendoza-González, 1985:48; León-Álvarez and González-González, 

1993:461.

Lithothamnion australe f. americana Foslie in Weber-van Bosse and Foslie, 

1904:25; Dawson, 1944a:271, pl. 56: figs. 5–10, pl. 57: figs. 11–16; 

Taylor, 1945:173; Dreckmann, 1991:34; León-Álvarez and GonzálezGonzález, 1993:462; González-González et al., 1993:240; RiosmenaRodríguez and Woelkerling, 2000:334.

Lithothamnion australe f. americana Foslie, 1904:25, nom. invalid. [see 

Woelkerling, 1993:25].

Crusts unattached rhodoliths, variable in form; some compact rounded to irregularly shaped nodules (up to 4 cm long, 

0.5–2.5 cm in diameter) with conspicuous short, irregular 

knobby protuberant branches 2–3 mm in diameter; others forming irregularly organized clumps (or individual branches) of long, 

mostly slender, divaricate to irregular branched, subcylindrical 

branches, 0.5–2 mm diameter. Hypothallium cells 10–20(–24) 

μm long by 7–11(–14) μm wide. Perithallium relatively thin, of 

quadrangular cells, 6–11 μm long by 5–11 μm in diameter.

Sporangial conceptacles apparently rare in Gulf of California, slightly protruding, 400–550 μm in outside diameter; multiporate. Gametangial thalli not recorded in Gulf of California 

(Dawson, 1960b).

Habitat. Rhodolith nodules; subtidal, 4–12 m 

depths, dredged down to 30 m depths.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda (Islas de la Cintura); Bahía Concepción 
NUMBER 96 • 135

to Isla Espíritu Santo and La Paz; Laguna Agiabampo; Sinaloa 

to Jalisco; Isla María Magdalena (Islas Marias). Eastern Pacific: 

Santa Catalina and Anacapa Island (California Channel Islands) 

to northern Baja California; Isla Guadalupe; Isla Cedros; Isla 

Clarión and Isla Socorro (Islas Revillagigedo); Guerrero; Panama.

Type Locality. Gulf of California (Foslie in Webervan Bosse and Foslie, 1904:25); “Probably on sublittoral banks,” 

vicinity of La Paz (Dawson, 1960b:11), Baja California Sur, Gulf 

of California, Mexico.

Remarks. Free-living nodules of Lithothamnion australe can often form extensive rhodolith beds at 10–30 m depths. 

Their movement within the benthic rhodolith beds may exclude 

the growth of some other algae and invertebrates, as well as remove them, either seasonally or during storms, such as the chubascos (violent squalls with rough seas) that originate in the Gulf 

of California or off Pacific Mexico and move into the Gulf. 

Lithothamnion microsporum (Foslie) Foslie

FIGURE 60

Lithothamnion californicum Foslie f. microsporum Foslie, 1902:5; Woelkerling, 1993:149. 

Lithothamnion microsporum (Foslie) Foslie, 1929:51; Johansen, 1976a:386, 

fig. 326; Pacheco-Ruíz and Aguilar-Rosas, 1984:76; Stewart and 

Stewart, 1984:143; Dreckmann, 1991:34; Mateo-Cid and MendozaGonzález, 1991:20; Stewart, 1991:79; González-González et al., 

1996:241; L. Aguilar-Rosas et al., 2000:131; Riosmena-Rodríguez and 

Woelkerling, 2000:342; Fernández-García et al., 2011:62.

Leptophytum microsporum (Foslie) Athanasiadis et W. H. Adey, 2006:101, 

figs. 123–125 [lectotype], 126–141; Athanasiadis, 2007:240.

Lithothamnion lenormandii sensu Dawson, 1960b:20, pl. 11: figs. 4–6, pl. 

14: fig. 2; 1961b:414 [non Lithothamnion lenormandii (Areschoug) 

Foslie, 1895a:178; basionym: Melobesia lenormandii Areschoug, 

1852:514; =Phymatolithon lenormandii (Areschoug) W. H. Adey, 

1966b:325 (see Johansen, 1976a:386)].

Crusts pinkish to rose, often spreading 2 cm or more in 

diameter, with smooth surface (or sometimes slightly irregular 

or squamulose under magnification); thin, Gulf material mostly 

100–200 μm thick; closely adherent to substratum. Hypothallium mostly 50–70(–100) μm thick; of 7–8 layers of small cells; 

cells about 12 μm long, 5 μm wide; with occasional patches 

of coaxial filaments (arching tiers of laterally aligned cells). 

Perithallium 25–100(–200) μm thick; of subspherical, periclinally slightly compressed or ovoid cells, 3–6 μm tall, (4–)5–7 

μm wide. Epithallium of flattened cells (in vertical section), although often missing due to sloughing. 

Reproductive conceptacles flush with the surface or only 

very slightly raised (up to 80 μm above surface); 160–280(–330) 

μm in outside diameter. Sporangial conceptacles multiporate, 

with (16–)25–40 pores per conceptacle; each pore in surface view 

surrounded by a rosette of 6–7 epithallial cells; tetrasporangia 

70–90 μm long, 20–40 μm in diameter; bisporangia 60–110 μm 

FIGURE 59. Lithothamnion australe: Free-living rhodoliths, subcylindrical branches with a wide range of forms. A, B. EYD-61-

40; C. EYD-593a (AHFH, now UC).

FIGURE 60. Lithothamnion microsporum: Surface view of two crusts. A. JN-3532; B. JN-3462 (both US Alg. Coll.).
136 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

long, 15–50 μm in diameter. Carposporangial conceptacles uniporate, “about 300 μm in outside diameter” (Dawson, 1960b:20; 

but not found on his material by Athanasiadis and Adey, 2006). 

Spermatangia unknown in Gulf (description after Athanasiadis 

and Adey, 2006, as Leptophytum microsporum).

Habitat. On hard surfaces, usually on pebbles or 

rocks or sometimes on other crustose corallines; intertidal to 

shallow subtidal. 

Distribution. Gulf of California: Puerto Peñasco 

to San Felipe; Guaymas. Eastern Pacific: Puget Sound, Washington, to Santa Catalina Island (California Channel Islands); 

Popotla (south of Rosarito), Baja California; Isla Magdalena 

(west side of Bahía Magdalena), Baja California Sur; Isla Guadalupe; Colima; Oaxaca. 

Type Locality. On pebbles and sandstone; Pacific 

Beach, near San Diego, San Diego County, southern California, 

USA.

Remarks. Distinctions between the Gulf of California Lithothamnion microsporum and some of the other species 

with smooth surfaces are often unclear, and its species limits and 

taxonomy need to be clarified in comparisons with type materials. In the field it can sometimes be confused with Spongites 

decipiens; however, differences in the sporangial conceptacles, 

seen with hand lens or microscope, distinguish these two: the 

multiporate conceptacles of L. microsporum versus uniporate 

tetrasporangial conceptacles in S. decipiens.

Lithothamnion microsporum has been treated as Leptophytum microsporum (Foslie) Athanasiadis et W. H. Adey 

(2006). However, the generitype, Leptophytum leave (Strömfelt) 

W. H. Adey (1966b) was based on Lithophyllum leave Strömfelt (1886), which as a later homonym of Lithophyllum leave

Kützing (1847) is an illegitimate name. Düwel and Wegeberg 

(1996) treated Leptophytum W. H. Adey as a new name based 

on a designated epitype, and concluded the type materials were 

conspecific with Phymatolithon lenormandii (Areschoug) W. H. 

Adey (1966b), making Leptophytum a heterotypic synonym of 

Phymatolithon Foslie (1898; see also: Woelkerling et al., 2002; 

Maneveldt et al., 2008; Guiry and Guiry, 2011). An earlier proposal by Athanasiadis and Adey (2003) to conserve Lithophyllum leave with a new conserved type was rejected (Compère, 

2004; Barrie, 2006; Prud’homme van Reine, 2011). Therefore a 

new genus may be needed for the generic concept of “Leptophytum sensu Adey” (Adey, 1966b; Adey et al., 2001; Athanasiadis 

and Adey, 2003; Athanasiadis, 2004; Athanasiadis and Adey, 

2006). The other species, including L. microsporum, need reinvestigation to determine whether they belong in Lithothamnion, 

Phymatolithon, in another genus, or possibly a new one.

Lithothamnion muelleri Lenormand ex Rosanoff

Lithothamnion muelleri Lenormand ex Rosanoff in Rosanoff, 1866:101, pl. 

6: figs. 8–11; Woelkerling, 1983b:190, figs. 29–33; Wilks and Woelkerling, 1995:553, figs. 1–6; Woelkerling, 1996a:181, figs. 76A–E, 77A–B; 

Rivera et al., 2004:235; Foster et al., 2007:367; Riosmena-Rodríguez et 

al., 2010:58, tbl. 3.1, fig. 3.3C.

Lithothamnion crassiusculum sensu Frantz et al., 2000:1773 [non Lithothamnion crassiusculum (Foslie) L. R. Mason, in Setchell and Mason, 

1943b:93; basionym: Lithothamnion rugosum f. crassiusculum Foslie, 

1901a:4, which is now Mesophyllum crassiusculum (Foslie) Lebednik 

in Athanasiadis et al., 2004:152; Athanasiadis, 2007:223].

Crusts spreading on substratum or forming rhodoliths; 1.0–

4.0 cm wide, 0.1–4 mm thick, with a lumpy surface; protuberances simple to branched, 1–6 mm long, 1–4 mm in diameter; 

attached by cell adhesion. Structure pseudoparenchymatous; dorsiventrally organized in crustose portions; radially arranged in 

protuberances. Thallus construction monomerous, with a single 

system of branched filaments giving rise to a ventral core in crustose portions and central core in protuberant branches and forming the peripheral areas where portions of core filaments or their 

branches curve outward to thallus surface; some cells of adjacent 

filaments adjoined by cell fusions; cells of filaments, 2.0–15 μm 

in diameter and to 2.0–30 μm long. Epithallial cells, 1.0–8.0 μm 

long and 2.0–8.0 μm in diameter, terminating most filaments at 

thallus surface, with distal cell walls flattened and flared. Secondary pit connections, haustoria, and trichocytes unknown.

Sporangia developed in multiporate conceptacles, with flush 

to protruding roofs; zonately divided tetrasporangia, 100–175 

μm tall, 30–140 μm in diameter, with an apical plug that blocks 

the roof pore prior to spore release. Pore canals, in vertical section, with bordering filaments with cells similar in size and shape 

to other roof filaments. Gametangial thalli not reported in Gulf 

(description of species after Woelkerling, 1996a).

Habitat. Usually a rhodolith, often in sediment 

patches and among rocks and Sargassum, mostly in wave-exposed 

sites; intertidal to shallow subtidal, down to 12 m depths.

Distribution. Gulf of California: Cabo Los Mochis (entrance to Bahía Concepción) to La Paz.

Type Locality. Western Port Bay, Victoria, Australia.

Remarks. Lithothamnion muelleri has been recently 

reported in the Gulf of California (Foster et al., 2007; RiosmenaRodríguez et al., 2010). Usually considered a cool-water species, 

L. muelleri had been known from southern Western Australia 

to South Australia and Tasmania and Victoria (Woelkerling, 

1996a). Woelkerling (1996a) also noted that records of L. muelleri from the subantarctic (Papenfuss, 1964b) and southern Chile 

(Hariot, 1895; Ramírez and Santelices, 1991) need to be confirmed. The finding of L. muelleri in the warm waters of the Gulf 

is interesting and, if confirmed, represents an extraordinary disjunct distribution from Australia and in the Gulf of California.

Melobesia J. V. Lamouroux

Melobesia J. V. Lamouroux, 1812:186 [see Mason, 1953:320, 335; Woelkerling, 1988: 113, 119, 186].

Melobesia Heydrich, 1897c:408, nom. illeg. [later homonym of Melobesia

J. V. Lamouroux, 1812]; Mason, 1953:320, 335.

Melobesia Foslie, 1898:10, nom. illeg. [later homonym of Melobesia J. V. 

Lamouroux, 1812]; Foslie, 1909:56; Mason, 1953:320, 335; Woelkerling, 1988:119; Woelkerling and Lamy, 1998:278].
NUMBER 96 • 137

Epilithon Heydrich, 1897c:408.

Hapalidium Kützing, 1843:385. 

Crusts thin, lightly calcified, usually epiphytic on other 

algae (or rarely epizoic), normally encrusting and attached to the 

surface of various hosts or substrates. Crusts flat or with undulating surfaces; without protuberances or branches. Thalli dorsiventrally organized and dimerous in construction. A single basal 

layer of first-order (primigenous) filaments is composed of palisade or nonpalisade cells. Second-order (postigenous) filaments 

of one or more cells may arise perpendicularly from the dorsal 

surface of the cells of the basal primigenous filaments. Some cells 

of adjacent filaments are adjoined by cell fusions; secondary pit 

connections and trichocytes are unknown. Each upright row of 

cells (filament) usually terminates with an outermost round or 

flattened epithallial cell or cells. 

Sporangial conceptacles are multiporate and produce zonately divided tetrasporangia or bisporangia. Each sporangium 

produces an apical plug that blocks its pore in the conceptacle 

roof prior to its release. Gametophytes are monoecious or dioecious. Carpogonia and spermatangia (where known) are 

developed in separate, uniporate conceptacles. Unbranched 

carpogonial filaments of 2–3 cells develop from the chamber 

floor within carposporangial conceptacles. Carposporophytes 

have 1 or possibly more inconspicuous fusion cells (or lack an 

evident fusion cell), with gonimoblast filaments of several cells 

that bear terminal carposporangia. Spermatangia are developed 

on unbranched filaments arising from the chamber floor, walls, 

and roof of the spermatangial conceptacle (after Harvey et al., 

2003a).

Remarks. The generic name Melobesia has been 

used three times to describe different taxa, i.e., Lamouroux 

(1812), Heydrich (1897c), and Foslie (1898). The last two are 

later homonyms, which are not to be taxonomically confused 

with Melobesia J. V. Lamouroux (Woelkerling in Guiry and 

Guiry, 2009). This has led to a confused taxonomic history and 

associated nomenclature (Mason, 1953; Woelkerling, 1988). 

Taxonomic and morphological data elucidating Melobesia can 

be found in Chamberlain (1985), Wilks and Woelkerling (1991), 

Woelkerling (1996, 1998), Woelkerling and Lamy (1998), Harvey et al. (2003a, 2003b), Woelkerling and Chamberlain (2007), 

Le Gall and Saunders (2007), and Woelkerling et al. (2008). 

Five species of Melobesia are presumed to be in the Gulf of 

California. In this treatment, two of these species are reported in 

the southern Gulf, and one is from the oceanographic entrance 

to the Gulf of California. They are all included since these small, 

often delicate, epiphytic crusts are easily overlooked and are 

probably more widespread in the Gulf of California than current 

records indicate. All Gulf specimens are in need of critical morphological and genetic study to determine their generic placement and specific status.

KEY TO THE SPECIES OF MELOBESIA IN THE GULF OF CALIFORNIA

1a. Crusts of only 1–2 layers of cells in vegetative portions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Crusts more than 2 layers thick, multilayered, of 7–25 layers of cells in vegetative portions . . . . . . . . . . . . . . . . . . . . . 3

2a. Crust only a single layer of cells in vegetative portions (overgrowth of individuals may form up to 5–6 layers); conceptacles hemispherical, 100–180 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. accola

2b. Crusts of 1–2 cell layers (50–100 μm thick) in vegetative portions; sporangial conceptacles mostly 110–130 μm in 

diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. membranacea

3a. Mature crusts of 12–25 layers of cells; conceptacles immersed (not prominent), with many cell layers below chamber 

floor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. polystromatica

3b. Mature crusts usually thinner; up to 12 cell layers thick; conceptacles protruding above surface (not immersed), with only 

1–2 cell layers below chamber floor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Epiphytic on various, noncalcified algae; juvenile crusts orbicular in outline, later forming confluent, irregularly shaped 

patches, up to 9 mm across; 50–150 μm thick; sporangial conceptacles up to 120 (rarely to 150) μm in outside diameter, 

with 10–12 pores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. marginata

4b. Epiphytic on sea grass blades; irregular in outline, up to 2 mm wide; usually less than 50 μm thick; overlapping individuals coalescing, up to 200 μm thick; sporangial conceptacles up to 210 μm in outside diameter, with 9–14 pores . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. mediocris

Melobesia accola (Foslie) Me. Lemoine

Litholepis accola Foslie, 1907:22; Setchell and Gardner, 1930:176; Dawson, 1960b:59; 1961b:417; Adey and Lebednik, 1967:36; Stewart and 

Stewart, 1984:143; Woelkerling, 1993:15; González-González et al., 

1996:237,400; Woelkerling, 1998:296, 397, figs. 140 (holotype), 141; 

Serviere-Zaragoza et al., 2007:10.

Melobesia accola (Foslie) Me. Lemoine, 1924:289, fig. 32e.

Lithoporella accola (Foslie) W. H. Adey, 1970:14; Ramírez and Santelices, 

1991:213.

Lithophyllum accola (Foslie) Woelkerling ex Dreckmann, 1991:34, comb. 

inval.; León-Álvarez and González-González, 1993:470; Fragoso and 

Rodríguez, 2002:112.

Crusts small, epiphytic on other crustose corallines; thin, 

monostromatic (a single layer of cells), individual crusts overgrowing each other and becoming up to 5–6 cell layers thick. Cells 

(in vertical section) rectangular to slightly vertically elongated or 

irregular, 5–10 μm tall, 5–12 μm wide; cells (in surface view) rectangular to rounded, 7–10 μm by 5–7 μm, arranged in rows.
138 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Conceptacles numerous, hemispherical-conical, 100–180 

μm in diameter, with a single pore. Gametangial conceptacles 

unknown (after Dawson, 1960b).

Habitat. Growing on other crustose coralline algae; 

intertidal.

Distribution. Gulf of California: Jalisco. Eastern 

Pacific: Isla Guadalupe; Isla Clarión and Isla San Benedicto (Islas 

Revillagigedo); Colima to Oaxaca; Hanga Piko, Rapa Nui (Easter Island; Isla de Pascua).

Type Locality. Tahiti (Dawson, 1960b); Hao (Haorangi), east of Tahiti, coral atoll in central part of Tuamotou 

Archipelago, French Polynesia (Woelkerling, 1998).

Remarks. Melobesia accola has not been recently 

collected, and it remains poorly known in the Gulf (Dawson, 

1960b, as Litholepis accola). Dawson (1960b) noted conceptacles 

with a single pore in Pacific Mexico specimens and questioned if 

they were asexual. However, only multiporate sporangial conceptacles are known in the genus Melobesia. The specimens and 

more collections are needed for further study to confirm their 

identification and its presence in the Gulf of California.

Melobesia marginata Setchell et Foslie

Melobesia marginata Setchell et Foslie in Foslie, 1902:10; Smith, 1944:219, pl. 

49: fig. 2, pl. 50: fig. 1; Taylor, 1945:176; Mason, 1953:321; Dawson, 

1960b:6, pl. 1: fig. 6, pl. 2: fig. 1; 1961b:413; Dawson et al., 1964:42, pl. 

33: fig. B; Johansen, 1976a:388, fig. 331; Silva, 1979:319; Stewart and 

Stewart, 1984:143; Pacheco-Ruíz and Aguilar-Rosas, 1984:76; Scagel et 

al., 1989:209; R. Aguilar-Rosas et al., 1990:124; Dreckmann, 1991:34; 

Stewart, 1991:79; Ramírez and Santelices, 1991:218; León-Álvarez 

and González-González, 1993:462; Woelkerling, 1993:145; R. AguilarRosas and Aguilar-Rosas, 1994:520; González-González et al., 

1996:243, 323, 403; Riosmena-Rodríguez and Woelkerling, 2000:342; 

Serviere-Zaragoza et al., 2007:11; Fernández-García et al., 2011:62.

Lithothamnion marginatum (Setchell et Foslie) Nichols, 1909:350, pl. 10: 

fig. 1, pl. 11: figs. 7–9, pl. 13: fig. 25.

Crusts thin, of 2 cell layers in vegetative portions, 50–100 μm 

thick; initially in surface view orbicular, later forming confluent, 

irregularly shaped patches, up to 9 mm wide, with lobed margins; 

of 8–12 cell layers thick centrally; central cells square to rectangular, 3–6 μm wide, 6–20 μm long. Basal layer of cells, 3–9 μm in 

diameter; epithallial cells somewhat triangular in vertical section.

Sporangial conceptacles crowded, protruding, usually 50–

100 μm tall; mostly 110–120 μm (rarely up to 150 μm) outside diameter; roof with 10–12 pores; tetrasporangia zonately 

divided, 40–60 μm long, 18–30 μm in diameter. Carposporangial conceptacles 95–125 μm tall, 125–150 μm outside diameter. 

Spermatangial conceptacles conical, 100–125 μm outside diameter (after Mason, 1953; Dawson, 1960b).

Habitat. Epiphytic on Sargassum, Gelidium, and 

Laurencia and probably other algae; intertidal.

Distribution. Gulf of California: Cabeza Ballena; 

Jalisco. Eastern Pacific: northern British Columbia to Punta 

Hughes, northwest side of Isla Magdalena (Bahía Magdalena), 

Baja California Sur; Islas Todos Santos, Isla Guadalupe, and Isla 

Cedros (Baja California); Isla Socorro and Isla San Benedicto 

(Islas Revillagigedo); Oaxaca; El Salvador; Costa Rica; Ecuador; 

Peru; Galápagos Islands.

Type Locality. On Gymnogongrus and Laurencia; 

Bodega Bay, Sonoma County, northern California, USA.

Melobesia mediocris (Foslie) Setchell et L. R. Mason

Lithophyllum zostericola f. mediocris Foslie, 1900d:5.

Melobesia mediocris (Foslie) Setchell et L. R. Mason, 1943b:95; Smith, 

1944:219, pl. 49: fig. 1; Taylor, 1945:176; Dawson, 1950a:68; 1951:52; 

Mason, 1953:320, pl. 31: fig. a; Dawson, 1957a:7; 1960b:7, pl.1: fig. 

5, pl. 2: figs. 2, 3; Dawson et al., 1960a:68, pl. 19: figs. 4, 5; Dawson, 1961b:413; R. K. S. Lee, 1970:437; Abbott and North, 1972:76; 

Johansen, 1976a:389, fig. 332; Huerta-Múzquiz, 1978:335; Silva, 

1979:319; Stewart and Stewart, 1984:143; Pacheco-Ruíz and AguilarRosas, 1984:71, 76; Ortega et al., 1987:73; Scagel et al., 1989:209; 

R. Aguilar-Rosas et al., 1990:124; Dreckmann, 1991:34; Stewart, 

1991:79; R. Aguilar-Rosas and Aguilar-Rosas, 1994:520; GonzálezGonzález et al., 1996:243; Silva et al., 1996b:232.

Lithothamnion mediocre (Foslie) Foslie et Nichols in Nichols, 1908:347, 

pl. 9.

Crusts thin, epiphytic on sea grasses; initially more or less discoid, spreading and often coalescing to become irregularly shaped 

(surface view outline), up to 2 mm wide; margins 7–12 μm thick; 

central vegetative portions 15–25 μm thick; fertile portions mostly 

30–65 μm thick (overgrowing or coalescing portions may be up 

to 200 μm thick). Margins of (1–)2 cell layers; centrally 7–11 cells 

thick, forming 3 different layers: basal (hypothallium) of 1–2 layers of cells, 6–8(–14) μm in diameter; erect filaments (perithallium) 

of 4–7 layers of cells about 10 μm tall, 8 μm wide; epithallium of 

2 layers of flat cells, 1–4 μm tall, 12 μm wide.

Reproductive conceptacles protruding above surface. Sporangial conceptacles dome shaped, 140–210 μm in diameter, 

90–140 μm tall; multiporate, with (4–)9–14 pores; tetrasporangia zonately divided, 50–125 μm tall, 35–80 μm in diameter. 

Carpogonial conceptacles 125–190 μm in diameter, 70–150 μm 

tall. Spermatangial conceptacles 75–120 μm in diameter, 65–75 

μm tall; spermatia ovoid with minute knob on each end, about 

3.7–4.0 μm long, 1.8–2.0 μm in diameter.

Habitat. Epiphytic on sea grasses; intertidal to very 

shallow subtidal.

Distribution. Gulf of California: Laguna Agiabampo (Sonora and Sinaloa). Eastern Pacific: northern British Columbia to Punta Hughes, northwest end of Isla Magdalena (Bahía 

Magdalena), Baja California Sur; Islas Todos Santos and Isla 

Guadalupe, Baja California; Rocas Alijos, Baja California Sur.

Type Locality. On the sea grass Phyllospadix; 

Santa Cruz, Santa Cruz County, northern California, USA.

Remarks. Melobesia mediocris is very similar to M. 

marginata; the two are generally separated by their alga or plant 

hosts. Melobesia mediocris is epiphytic on sea grasses, and M. 

marginata is on various fleshy algae. The obligate specificity of 

their plant or algal hosts needs to be tested, and their relationship needs to be elucidated by molecular studies.
NUMBER 96 • 139

Melobesia membranacea (Esper) J. V. Lamouroux

Corallina membranacea Esper, 1796: pl. Corallina XII: figs. 2–4.

Melobesia membranacea (Esper) J. V. Lamouroux, 1812:186; Mason, 

1953:319; Dawson, 1960b:8, pl. 25: figs. 1–3; 1961b:413; HuertaMúzquiz and Garza-Barrientos, 1975:8; Chamberlain, 1983:297–

298; 1985:673, fig. 2; Woelkerling, 1988:189; Dreckmann, 1991:34; 

León-Álvarez and González-González, 1993:462; Chamberlain and 

Irvine, 1994b:196, figs. 7B, 39A, 75, 93, 94; González-González et 

al., 1996:323, 403; Riosmena-Rodríguez and Woelkerling, 2000:342; 

Fragoso and Rodríguez, 2002:130; Serviere-Zaragoza et al., 2007:11; 

Woelkerling and Chamberlain, 2007:233.

Epilithon membranaceum (Esper) Heydrich, 1897c:408; Hamel and 

Lemoine, 1953:112, figs. 77–81, pl. 22: figs. 6, 7.

Crusts thin, delicate, orbicular, spreading up to 1 cm (or 

more) in diameter, usually epiphytic on various larger algae, rarely 

epizootic or on rocks; flattened, closely adherent to host; only 1–2 

cell layers and 25–45 μm thick in vegetative portions; 4–5 cell layers and 55–90 μm thick in reproductive regions. Dimerous with 

cell fusions present and trichocytes absent. Single basal layer (hypothallium) of cells in vertical section about 7–23 μm tall, 2–6 μm 

in diameter; erect filaments (perithallium) either absent or up to 

7 cells; if present, cells about 2–13 μm tall, 3–10 μm in diameter 

(cell sizes not given by Dawson, 1960b; after Chamberlain and 

Irvine, 1994b). Epithallial cells irregularly present; very small, 1⁄3

to 1⁄2 diameter of vegetative cells (Dawson, 1960b).

Sporangial conceptacles prominent, dome shaped or hemispherical, small (80–)110–130(–150) μm outside diameter, single 

or grouped, sometimes confluent; roof multiporate, 7–20(–30) 

pores; tetrasporangia 35–90 μm long, mostly zonately divided 

with a apical pore plug. Carposporangial conceptacles dome 

shaped, 120–200(–300) μm outside diameter. Spermatangial 

conceptacles conical, about 100 μm inside diameter, up to 

250 μm outside diameter.

Habitat. Epiphytic on Chaetomorpha and probably 

on other algae; intertidal.

Distribution. Gulf of California: Cabeza Ballena; 

Jalisco. Eastern Pacific: Isla Socorro and Isla San Benedicto (Islas 

Revillagigedo); Guerrero.

Type Locality. On red algae, west coast of France.

Remarks. Melobesia membranacea is the type species of the genus Melobesia. The species is easily overlooked and 

is probably more widely distributed in the Gulf of California 

than current records indicate.

Melobesia polystromatica E. Y. Dawson

Melobesia polystromatica E. Y. Dawson, 1960b:8, pl. 1: fig. 4, pl. 22: fig. 2; 

Dawson, 1961b:413; Anderson, 1991:32; León-Álvarez and GonzálezGonzález, 1993:462; Serviere-Zaragoza et al., 1993a:484; GonzálezGonzález et al., 1996:243, 403; Riosmena-Rodríguez and Woelkerling, 

2000:344; Fernández-García et al., 2011:62.

Crusts, epiphytic on Sargassum, mostly 5–8 mm in diameter, individuals unevenly thick, varying 100–200 (or more) μm 

in thickness. Initially a thin, lightly calcified single cell layer of 

radiating rows of quadangular cells, 6–10 μm long by 3–5 μm 

wide; soon becoming polystromatic, thicker and heavily calcified, confluent, and somewhat mounded; spreading on flat surfaces or surrounding cylindrical portions of algal host. A single 

basal layer (hypothallium) (in vertical section) of squarish cells, 

6–7 μm in diameter; erect filaments (perithallium) of 15–20 cells 

in vertical rows, cells 7–12 μm long, epithallium of 4–5 layers 

of small, quadrate to flattened cells. In surface view, superficial 

epithallial cells rounded, 4–5 μm in diameter, with thick walls.

Sporangial conceptacles immersed (not prominent), with 

oval chamber, about 60 μm high by 110 μm inside diameter; 

conceptacle roof with 20–25 pores; tetrasporangia zonately divided, 25–30 μm long. Carposporangial conceptacles immersed; 

chambers about 110 μm inside diameter, roof with a single pore. 

Spermatangial conceptacles with chambers about 80 μm inside 

diameter (description after Dawson, 1960b).

Habitat. On Sargassum and probably other algae; 

intertidal to shallow subtidal. 

Distribution. Gulf of California: Nayarit to 

Jalisco. Eastern Pacific: Oaxaca; El Salvador.

Type Locality. On Sargassum liebmannii J. Agardh: 

Bahía Tenacatita, Jalisco, Pacific Mexico.

Remarks. A little known species, Melobesia polystromatica is distinguished by its polystromatic thallus and immersed reproductive conceptacles. Dawson (1960b) noted 

M. polystromatica had much in common with some of the thin 

species of Lithothamnion. Present in the southern end of the Gulf 

of California, it is included to call attention to the need for further morphological and molecular study of its taxonomic status.

Mesophyllum Me. Lemoine

Mesophyllum Me. Lemoine, 1928:251; Woelkerling, 1988:193; Harvey et 

al., 2003a:998; 2003b:647; Le Gall and Saunders, 2007:1118.

Crustose corallines vary in appearance from encrusting with 

smooth surfaces to those with warty or lumpy protuberances and 

others that are foliose or fruticose. Species may be epiphytic or 

epizoic, on rocks or shells, or may form unattached rhodoliths. 

Thallus construction is monomerous, internally composed of a 

core of coaxial hypothallial filaments (cells laterally aligned in 

arching tiers) parallel to the substratum that then shift upward, 

curving toward the upper surface. The ascending filaments form 

the more or less stratified perithallium. Most of the filaments terminate with an epithallial cell at the thallus surface. Epithallial 

cells have rounded or flattened outermost walls that do not flare at 

the corners. Cell elongation usually occurs within the dividing subepithallial meristematic cells that are usually as long as or longer 

than their immediate inward derivatives. Cells fusions are present 

between some cells of adjacent filaments; secondary pit connections are absent (after Guiry and Guiry, 2008–2010). Trichocytes 

are generally absent but have been reported in a few of the species. 

Bisporangia and zonately divided tetrasporangia are developed in sporangial conceptacles with multiporate roofs. Prior 

to their release, each sporangium has an apical plug that blocks 

a roof pore. Carpogonia and spermatangia, where known, are 
140 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

produced in separate uniporate conceptacles either on the same 

or on different thalli. Carpogonia are terminal on 2- to 4-celled 

unbranched filaments developed from the conceptacle chamber 

floor. After presumed fertilization the carposporophytes develop 

in dumbbell-shaped female conceptacle chambers. Mature carposporophytes apparently lack a large central fusion cell but are 

composed of an irregularly shaped fusion cell or a several-celled 

fusion cell complex (not always evident). Carposporangia are terminal on gonimoblast filaments of several cells. Spermatangia are 

developed on unbranched filaments that arise from the conceptacle chamber floor and roof. Spermatangial initials (spermatangial 

parent cells) in the early stages are covered by a layer of “protective cells” that soon degenerates.

Remarks. One species is reported in the southern 

Gulf: Mesophyllum engelhartii (Foslie) W. H. Adey (1970; basionym: Lithothamnion engelhartii Foslie, 1900f ) from Punta 

Perico (Riosmena-Rodríguez and Vásquez-Elizondo, 2012). 

Currently there is one species of Mesophyllum recorded in the 

northern Gulf of California.

Mesophyllum crassiusculum (Foslie) Lebednik

FIGURE 61

Lithothamnion rugosum f. crassiusculum Foslie, 1901a:4, as ‘crassiuscula.’

Mesophyllum crassiusculum (Foslie) Lebednik in Athanasiadis et al,, 

2004:152, figs. 119–149; Athanasiadis, 2007:223, figs. 61–63, tbl. 2.

Lithothamnion pacificum f. crassiusculum (Foslie) Foslie, 1906b:10.

Lithothamnion crassiusculum (Foslie) L. R. Mason in Setchell and Mason, 

1943b:93; Johansen, 1976a:384, fig. 324; Stewart, 1991:79; Bernecker 

and Wehrtmann, 2009:225; Fernández-Garcia et al., 2011:63.

Lithothamnion aculeiferum L. R. Mason in Setchell and Mason, 1943b:94; 

Mason, 1953:326, pl. 33: fig c; Dawson, 1960b:10, pl. 3: figs. 1–3, pl. 

5: fig. 1 [note: photo is upside down]; 1961b:413; Hollenberg and Abbott, 1966:59; Masaki, 1968:10, pls. 2, 3, 41; Johansen, 1976a:382, 

fig. 321; Stewart, 1991:78; González-González et al., 1996:239; Yoshida, 1998:582; Riosmena-Rodríguez and Woelkerling, 2000:334; 

Pacheco-Ruíz and Zertuche-González, 2002:467.

Lithothamnion fruticulosum sensu Dawson, 1960b:14[in part, southern Gulf 

of California specimens only; fide Johansen, 1976a:384], pl. 4: figs. 

21–25 [non Lithothamnion fruticulosum (Kützing) Foslie, 1895a:46; 

which is now Spongites fruticulosa Kützing, 1841:33].

Crusts pinkish purple, spreading up to 7 cm wide and 300–

800 μm thick; often overgrowing each other, becoming up to 

3 mm thick; surface with numerous small close together, short, 

simple protuberances of more or less similar size, 0.5–1.5 mm 

tall, (0.5–)1.0–1.5 mm in diameter at base; with angular to 

rounded or wart-like tops, 1.5–3.0 mm wide; strongly adhering to rocks or covering small pebbles; sometimes becoming 

nodular as free-living rhodoliths. Monomerous construction; 

hypothallium irregularly developed and patchy, 50–300 μm 

thick, predominately of coaxial filaments (laterally aligned cells 

in arching tiers), of cells 10–25(–30) μm long by 5–13 μm in 

diameter. Perithallium formed by curving hypothallial filaments 

as they continue to the thallus surface; perithallium more or 

less stratified, 50–800 μm thick; filaments of slightly elongate 

cells in lower portions, 4–23 μm long, (3–)4–9 μm in diameter, 

upward portions mostly of isodiametric or ovoid cells, 3–9 μm 

tall, 3–9 μm in diameter. Cell fusions common between cells of 

contiguous filaments. Epithallium of 1–3 layers of flattened cells, 

2–5 μm tall by 3–9 μm wide. Trichocytes absent.

Reproductive conceptacles scattered over crust and protuberances. Sporangial conceptacles crowded, (140–)220 μm tall, 

450–750 μm outside diameter; chambers (140–)180–240 μm 

FIGURE 61. Mesophyllum crassiusculum: A. Habit (EYD-4277, AHFH, now UC). B. Habit (EYD-2636, AHFH, now UC). C. Close-up of 

crust surface showing small short protuberances and sporangial conceptacles (EYD-2636, AHFH, now UC). 
NUMBER 96 • 141

tall, 300–450 μm inside diameter; multiporate convex roof, (30–) 

40–60 μm thick. Pore plates 260–470 μm in diameter, with (15–)

25–50 pores; each pore about 10 μm in diameter, bordered by 

6–10 rosette cells in surface view (Athanasiadis, 2007); in vertical 

section, pore canals straight, bordered by filaments of 6–8(–10) 

cells, cells thinner and some wider than cells of regular roof filaments. Tetrasporangia 110–175(–200) μm long, 25–70(–100) 

μm in diameter (after Athanasiadis, 2007). Carposporangial and 

spermatangial conceptacles not known in the northern Gulf.

Habitat. On rocks of various sizes or sometimes 

completely covering pebbles forming rhodoliths, or growing on 

rhodoliths; intertidal to shallow subtidal, down to 6 m depths.

Distribution. Gulf of California: Bahía de Los 

Ángeles, Bahía de Loreto. Eastern Pacific: Duxbury Reef, Marin 

County, to La Jolla, California; Cortez Bank (seamount, California Channel Islands); Isla Coronado del Sur (Islas Coronado, off 

Baja California ) to Isla Concha, Laguna Ojo de Liebre (Scammon’s Lagoon), Baja California Sur; Costa Rica. Western Pacific: 

Japan; Korea.

Lectotype Locality. White Point, White Point 

Park, San Pedro, Los Angeles County, southern California, USA.

Remarks. Mesophyllum crassiusculum has been 

reported in the northern Gulf from Bahía de Los Ángeles 

(Pacheco-Ruíz and Zertuche-González, 2002, as Lithothamnion 

crassiusculum) and without comment from Bahía de Loreto 

(CONANP, 2002, as L. crassiusculum); description is based in 

part on Dawson (1960b) and Athanasiadis (2007). RiosmenaRodríguez (in Riosmena-Rodríguez and Vásquez-Elizondo, 

2012) has suggested that M. crassiusculum may belong in the 

genus Lithothamnion. Its presence in the northern Gulf requires 

further investigation.

AHNFELTIOPHYCIDAE

Ahnfeltiophycidae G. W. Saunders et Hommersand, 2004:1504.

Subclass Ahnfeltiophycidae is characterized by having terminal and sessile carpogonia and a carposporophyte that develops outward. Ultrastructurally, the pit plug cores are either 

naked, without caps and membranes (Ahnfeltiales), or with cap 

membranes but without cap layers (Pihiellales; Pueschel and 

Huisman, 2010).

Remarks. The Ahnfeltiophycidae contains two orders: Ahnfeltiales, which is represented in the Gulf of California, 

and a monotypic order, Pihiellales Huisman, A. R. Sherwood et 

I. A. Abbott (2003).

Ahnfeltiales

Ahnfeltiales C. A. Maggs et Pueschel, 1989:349.

Members are distinguished primarily by characteristics of 

the female gametophyte. The carpogonia are terminal, sessile 

on filaments of the normal cortical layers within swollen nemathecia. Following fertilization, the carpogonium fuses with 

morphologically unmodified, contiguous cortical cells and develops outward from the cortex. There are no differentiated 

auxiliary cells. Gonimoblast filaments grow directly from the carpogonium, spreading over the surface of the sorus, fusing with 

vegetative and other gonimoblast cells and radiating outward and 

terminate in carposporangia. Members are agarophytes, with cell 

walls containing the agarocolloids. Ultrastructure studies have 

shown pit plugs that lack cap layers and cap membranes.

This order is represented by its single family in the Gulf of 

California.

Ahnfeltiaceae

Ahnfeltiaceae C. A. Maggs et Pueschel, 1989:348. 

Gametophytes are erect thalli arising from a spreading discoid base. Growth is multiaxial, with vegetative cells forming 

conjunctor cells that result in secondary pit connections and also 

fusing directly. Sexual reproduction is as for the order, with heteromorphic life histories. Several embryos develop from adjacent 

zygotes to produce compound external carposporophytes that 

are not surrounded by a pericarp. Spermatangia are cut off singly 

and transversely from parent cells on the thallus surface. Male 

gametophytes may also form monosporangia developed from 

modified cortical cells. The monospores reproduce the male gametophytes, recycling the male generation.

Monospores may develop from modified cortical cells. 

Tetrasporophytes are crustose, with the crusts exhibiting direct 

cell fusions, but lack secondary pit connections. Tetrasporangia 

develop within sori and are irregularly zonately divided.

The Ahnfeltiaceae is represented by one genus in the northern Gulf of California.

Ahnfeltia Fries

Ahnfeltia Fries, 1836:309; Silva, 1993a:128.

The only genus in the Ahnfeltiaceae, Ahnfeltia has the characteristics of the family.

Remarks. The generitype, Ahnfeltia plicata (Hudson) Fries (1836; basionym: Fucus plicatus Hudson, 1762), 

has been reported in the southern Gulf of California from El 

Requesón, Bahía Concepción, to the coral reef of Cabo PulmoLos Frailes (Anaya-Reyna and Riosmena-Rodríguez, 1996; 

Riosmena-Rodríguez et al., 1998). 

One species is reported in the northern Gulf of California.

Ahnfeltia svensonii W. R. Taylor

FIGURE 62

Ahnfeltia svensonii W. R. Taylor, 1945:238, pl. 77: fig. 2; Dawson, 1959a:26, 

fig. 3C; 1961a:247, pl. 42: fig. 1; 1961b:431; Huerta-Múzquiz, 

1978:339; Mendoza-González and Mateo-Cid, 1986:424; Mateo-Cid 

and Mendoza-González, 1992:21; Mendoza-González and MateoCid, 1992:19; Serviere-Zaragoza et al., 1993a:482; Mateo-Cid and 

Mendoza-González, 1994b:40; González-González et al., 1996:169; 

CONANP, 2002:136.
142 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Algae in tufts, 2–7 cm tall; dark red to blackish, of cartilaginous, terete to slightly compressed axes, usually 0.7–1.0 mm 

in diameter (rarely up to 2.0 mm); mostly divaricately dichotomously branched (occasionally polychotomous); upper branches 

1–2 mm long in smaller thalli, 5.0–10 mm long in larger thalli. 

Medulla of thick-walled large cells; surrounded by cortical layer 

of anticlinal rows of 3–4 small cylindrical cells.

Tetrasporangia not known. Cystocarps immersed within 

branches, projecting above branch surface; with a large, irregularly shaped pore; carpospore mass without a sterile base or center or pericarp. Spermatangia unknown.

Distribution. Gulf of California: Segundo Cerro 

Prieto to Roca Roja (both Bahía Kino); Loreto; Isla Cholla (off 

north end of Isla Carmén); Isla Espíritu Santo to Cabo San Lucas; 

Nayarit to Jalisco. Eastern Pacific: Playa Los Cerritos (south of 

Todos Santos), Baja California Sur; Galápagos Islands.

Type Locality. Black Beach, Isla Floreana (Charles 

Island; Isla Santa María), Galápagos Islands, Ecuador.

Remarks. Ahnfeltia svensonii has been reported in 

the southern Gulf (Dawson, 1959a, 1961a) and in the northern Gulf from Bahía Kino (Mendoza-González and Mateo-Cid, 

1986). Further collections will be helpful to make morphological 

and molecular comparisons of Gulf A. svensonii with the Galápagos A. svensonii from the type locality.

RHODYMENIOPHYCIDAE

Rhodymeniophycidae G. W. Saunders et Hommersand, 2004:1504.

Subclass Rhodymeniophycidae is characterized by pit plugs 

that are covered by a membrane only, with the exception of the 

Gelidiales (which have a single inner cap); all others lack cap 

layers. Life histories, where known, are mostly triphasic. The 

carposporophyte develops directly from the carposporangium of 

a carpogonial fusion cell or indirectly from an auxiliary cell that 

received a transferred diploid nucleus.

Remarks. The largest subclass of the Florideophyceae, the Rhodymeniophycidae is composed almost entirely of 

marine species; its members exhibit a very large diversity of 

morphologies.

The Rhodymeniophycidae is represented by 11 of its orders 

in the northern Gulf of California.

KEY TO THE ORDERS OF RHODYMENIOPHYCIDAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli primarly uniaxial in construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Thalli primarily multiaxial in construction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2a. Thalli medulla of longitudinal filaments, entwined with internal rhizoidal filaments (rhizines or hyphae) in most, but absent 

in one family; prostrate axes attach by rhizoidal filaments or small brush-like or peg-like holdfasts . . . . . . . . . . Gelidiales 

2b. Thalli medulla pseudoparenchymatous or filamentous, without rhizines; attached primarily by small or spreading discoid 

holdfasts or by rhizoidal or stoloniferous outgrowths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Auxiliary cells initiate carposporophyte development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3b. Auxiliary cells do not initiate carposporophyte development; carposporophyte arises directly from fertilized carpogonium or after its fusion with hypogynous cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

4a. Auxiliary cell an intercalary vegetative cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gigartinales (in part)

4b. Auxiliary cell not an intercalary vegetative cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5a. Auxiliary cell develops from a cell of fertile branch (filament), auxiliary cell normally cut off from the support cell of 

carpogonial branch after fertilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ceramiales

5b. Support cell of carpogonial branch functions as an auxiliary cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Plocamiales

6a. Carpogonial branch 2-celled with 2–3 sterile filaments; thalli initially uniaxial in construction (although appearing multiaxial); gametophytes and sporophytes isomorphic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gracilariales (in part) 

6b. Carpogonial branch 3- or 4-celled; axial filament usually conspicuous throughout most of thallus; gametophyes and 

sporophytes isomorphic or heteromorphic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bonnemaisoniales

7a. Thalli mostly crustose (a few partially erect); some with internal calcification, others not calcified; sexual reproductive 

structures in nemathecia on thallus surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Peyssonneliales

FIGURE 62. Ahnfeltia svensonii: Habit (EYD-18747, US Alg. Coll.-

6444).
NUMBER 96 • 143

7b. Thalli not usually crustose in habit; not usually calcified; sexual reproductive structures not in nemathecia on thallus 

surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

8a. Gametophytes with medulla of slender filaments and rhizoidal-like filaments; cortex of anticlinal filaments . . . . . . . 11

8b. Gametophytes with medulla and cortex not as above, usually pseudoparenchymatous in some portion of thallus . . . . . . 9

9a. Thalli with hollow and solid portions; hollow portions lined by longitudinal filaments, solid portions pseudoparenchymatous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rhodymeniales (in part)

9b. Thalli completely without hollow portions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

10a. Thalli with a pseudoparenchymatous medulla and cortex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

10b. Thalli with a filamentous medulla surrounded by a pseudoparenchymatous cortex . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 

11a. Algae firm, not usually gelatinous or mucilaginous in texture . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gigartinales (in part)

11b. Algae soft, “jelly-like,” usually gelatinous or mucilaginous in texture . . . . . . . . . . . . . . . . . . . . . . . . . Nemastomatales

12a. Tetrasporangia cruciately to decussately-cruciately divided; either in nemathecia or scattered or in sori over cortex; carposporophyte surrounded by involucres from ampullary filaments (Halymeniaceae) or among cortical filaments without 

ampullae (Tsengiaceae) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cryptonemiales

12b. Tetrasporangia cruciately to very irregularly divided (superficially appearing zonate), tetrasporangia either in nemathecia 

(two genera) or in cortex (e.g., Gulf of California Sebdenia flabellata); some dorsiventral organized; carposporophyte 

without involucre filaments, some surrounded by rudimentary cellular pericarp . . . . . . . . . . . . . . . . . . . . . Sebdeniales

13a. Auxiliary cell is terminal cell of a 2-celled filament borne on the supporting cell of carpogonial . . . Rhodymeniales (in part)

13b. Auxiliary cells absent, do not initiate carposporophyte development . . . . . . . . . . . . . . . . . . . . . . . Gracilariales (in part)

Bonnemaisoniales

Bonnemaisoniales Feldmann et Feldmann-Mazoyer, 1952:29.

Algae range from erect, large, and pseudoparenchymatous 

thalli to small, uniseriate to “polysiphonous-like” filaments, or 

prostrate crusts. Thalli are uniaxial in structure, with growth 

from a single apical cell, with subapical cells producing periaxial 

filaments. Life histories of the species involve isomorphic or heteromorphic gametophytes and sporophytes. Gametophytes may 

be monoecious or dioecious. Postfertilization development does 

not involve auxiliary cells; the gonimoblast develops directly 

from the fertilized carpogonium or after fusion with the hypogynous cell, and it has terminal carposporangia.

Heteromorphic tetrasporophytes are minute to small, uniseriate or trisiphonous filaments; or prostrate single-layered crusts. 

Cells of the filaments contain discoid chloroplasts that are usually numerous and without pyrenoids. Tetrasporangia are cruciately, tetrahedrally, or irregularly divided.

The order is represented by one of its families in the Gulf of 

California.

Bonnemaisoniaceae

Bonnemaisoniaceae F. Schmitz, 1892:20.

Gametophytes are erect, and cylindrical or compressed, and 

generally much branched, either radially, spirally branched, or 

distichousand bilaterally branched. The axial row of cells is usually evident and surrounded by branched rows of cells that become 

compacted outward to form a pseudoparenchymatous cortex of 

mixed large and small cells in a continuous surface layer. Cells have 

numerous discoid chloroplasts and are without pyrenoids. Highly 

refractive, vesicular cells (gland cells) are present in some species.

Life histories, where known, are isomorphic or with heteromorphic life phases. Culture studies of genera occurring in the Gulf 

have shown the sporophytic phase to be small polysiphonouslike filaments of “Falkenbergia” in Asparagopsis and uniseriate 

filaments of “Trailliella” in Bonnemaisonia. In the female gametophyte, the carpogonial branch is borne terminally on a indeterminate branchlet or borne laterally from inner cortical cells. 

The carpogonial branch is 3(–4)-celled and, in some genera, has 

branched sterile filaments from its lower two cells. Fusion of these 

structures occurs after fertilization as the gonimoblast develops. 

Gonimoblast filaments arise from this fusion cell and produce terminal carposporangia. Cystocarps are surrounded by a substantial 

cellular pericarp. Spermatangia are borne in dense superficial sori 

or on distinct ovoid to clavate stalked branchlets.

Remarks. The macroscopic gametophytes of two 

genera of the Bonnemaisoniaceae are present in the northern 

Gulf of California. Whereas the sporophytic phase, “Falkenbergia hillebrandii,” has been collected for northern Gulf Asparagopsis, the sporophyte, presumed to be the “Trailliella” phase 

for the Gulf Bonnemaisonia, is as yet undetected in the field.

KEY TO THE SPECIES OF BONNEMAISONIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Gametophytes erect, of several bushy (plumose) axes, arising above well-developed system of creeping, stoloniferous axes 

attached to the substrate by rhizoids; distal portions of ultimate branchlets with a cortex of rectangular, larger cells than 

those of the bearing branch [Figure 63B] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Asparagopsis taxiformis

1b. Gametophytes erect, mostly epiphytic, entangled with other algae by characteristic hamate (hook-shaped) branchlets 

[Figure 65C]; ultimate branchlets with cortex of numerous, small, rounded cortical cells similar to the cortex of bearing 

branch [Figure 65D] . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bonnemaisonia hamifera
144 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Asparagopsis Montagne

Asparagopsis Montagne, 1841:xv.

Falkenbergia F. Schmitz in Schmitz and Falkenberg, 1897:479.

Gametophytes are erect, soft in texture, with several stalked 

bushy axes, arising from entangled, creeping stoloniferous axes 

that attach to the substrate by tufts of rhizoids. The main axis 

and branches are terete to subterete and are richly branched 

above, but the lower portions are often unbranched. Branching 

is usually alternate to multifarious, up to several orders, appearing plumose. Each branch is covered with short branchlets on all 

sides. The medulla is a central axial row of cells, surrounded by 

an open gelatinous matrix and short, compact, cell rows. These 

rows of cells branch outward to form a continuous pseudoparenchymatous cortex several cells thick.

Tetrasporangia are produced by the morphologically different small sporophyte, the trisiphonous Falkenbergia-phase 

of the life history. Tetrasporangia are cruciately to irregularly 

divided. Gametophytes are monoecious or dioecious. Carpogonial branches 3-celled, with lateral nutritive cells from the lower 

cells. Cystocarps have a subpyriform pericarp with ostiole and 

are usually borne terminally on short branchlet. Spermatangia 

form a dense superficial layer on distinct ovoid to clavate head 

on stalked branchlets.

Remarks. Asparagopsis was the first red alga recognized to have a heteromorphic life history (Feldmann and 

Feldmann, 1939a, 1939b, 1943, 1952; Bonin and Hawkes, 

1987; Ní Chualáin et al., 2004). The macroscopic gametophytes of the northern Gulf of California Asparagopsis were 

found to contain interesting secondary metabolites (Fenical, 

1974; McConnell and Fenical, 1977a, 1979). Volatile halogenated compounds, mostly brominated and iodinated methanes 

and acetones, have also been reported in Asparagopsis from 

Hawaii (Burreson et al., 1976) and elsewhere in populations of 

the smaller, sporophytic phase, Falkenbergia (Marshall et al., 

1999, 2003).

One species of Asparagopsis (with both gametophytic thalli 

and the sporophytic Falkenbergia-phase) has been found in the 

northern Gulf of California.

Asparagopsis taxiformis (Delile) Trevisan

FIGURE 63

Fucus taxiformis Delile, 1813:295, pl. 57: fig. 2 [note: pls. published 1826]. 

Asparagopsis taxiformis (Delile) Trevisan, 1845:45, pl. 1; Dixon, 

1964:902; Chihara, 1970:64, pl. 32: fig. 4; Abbott and Hollenberg, 1976:340, figs. 282, 283; Huerta-Múzquiz, 1978:337, 340; 

Schnetter and Bula-Meyer, 1982:111, pl. 11: figs. R–T, pl. 12: fig. A, 

pl. 15: figs. G,H; Stewart and Stewart, 1984:142; Norris, 1985d:208, 

fig. 16.1; Huerta-Múzquiz and Mendoza-González, 1985:48; Santelices and Abbott, 1987:8; Sánchez-Rodríguez et al., 1989:42; 

Stewart, 1991:68; León-Tejera et al., 1993:200; Serviere-Zaragoza 

et al., 1993a:483; Bula-Meyer, 1995:33; Silva et al., 1996b:232; 

Anaya-Reyna and Riosmena-Rodríguez, 1996:864, tbl. 1; RiosmenaRodríguez et al., 1998:25; Yoshida, 1998:648, fig. 3-41C; Abbott, 

1999:174, fig. 43A–D; CONANP, 2002:136; Cruz-Ayala et al., 

2001:190; Pacheco-Ruíz and Zertuche-González, 2002:467; Ní Chualáin et al., 2004:1112, fig. 1a; Mateo-Cid et al., 2006:55; ServiereZaragoza et al., 2007:9; Y.-P. Lee, 2008:229, figs. A–C; Pacheco-Ruíz 

et al., 2008:207; Fernández-García et al., 2011:60.

Asparagopsis taxiformis (Delile) Collins et Hervey, 1917:117, nom. illeg.; 

Feldmann and Feldmann, 1943:81; Dawson, 1953a:57; 1957a:7; 

1959a:20; 1961b:408; Chihara, 1961:139, figs. 11–19; Chihara, 

1962:40–51, tbl. 2; Huerta-Múzquiz and Garza-Barrientos, 1975:8, 11.

Lictoria taxiformis (Delile) J. Agardh, 1841:22.

Asparagopsis delilei Montagne, 1841:xiv, nom. illeg.

Asparagopsis sanfordiana Harvey, 1855:544; Harvey, 1858: pl. VI; Okamura, 1908:135, 137, pl. XXVIII: figs. 1–12; Setchell and Gardner, 

1930; Okamura, 1936:431; Dawson, 1944a:257; Taylor, 1945:149; 

Dawson, 1949b:246; González-González et al., 1996:175; Ní Chualáin 

et al., 2004:1112, fig. 1b.

Asparagopsis sanfordiana f. amplissima Setchell et N. L. Gardner, 1924:760, 

pl. 22: fig. 3, pl. 41; Taylor, 1945:149; González-González et al., 

1996:175; Serviere-Zaragoza et al., 2007:9.

Polysiphonia hillebrandii Bornet in Ardissone, 1883:376.

Falkenbergia hillebrandii (Bornet) Falkenberg, 1901:689; Setchell and Gardner, 1930:163; Feldmann and Feldmann, 1943:89, figs. 3–6; Dawson, 1953a3:58; 1959a:20; Chihara, 1960:249; Huerta-Múzquiz and 

Garza-Barrientos, 1975:8; Abbott and Hollenberg, 1976:340, fig. 283; 

Pedroche and González-González, 1981:66; Sánchez-Rodríguez et al., 

1989:42; Ní Chualáin et al., 2004:1112, fig. 1d; Bernecker, 2009:CDRom p. 61.

Gametophytes brownish red to rosy pink to purplish red; 

composed of numerous erect, soft, plumose fronds up to 45 cm 

tall; axes arise from a group of terete, prostrate stolons attached 

to the substratum at various points by rhizoids. Fronds with a 

prominent, percurrent axis, 1.5–3.0 mm in diameter; densely, 

more or less alternately to irregularly spirally/multifariously 

branched, up to several orders; often lacking branches in lower 

third to half of thallus. Ultimate branchlets slender with pointed 

apices. Distal portion of ultimate branchlets with several boxy 

pericentral cells (30–45 μm long and about 30 μm in diameter) 

around each thin axial filament cell. Uniaxial; axis and principal 

branches with prominent central axial filament (surrounded by 

open space) that outwardly produces filaments that form a cylinder of peripheral, pseudoparenchymatous cells. Cortex of small 

pigmented cells.

Gametophytes dioecious. Cystocarps subspherical, ostiolate, up to 500 μm in diameter; borne terminally on short 

branchlets. Spermatangial heads terminal on unbranched laterals, heads ovoid to clavate, about 550 μm long and 265 μm wide, 

covered by dense surface layer of spermatangia.

Habitat. On rocks or sand; low intertidal to shallow 

subtidal, down to 10 m depths.

Distribution. Gulf of California: Rocas Consag 

to Punta Los Frailes; Nayarit to Jalisco. Eastern Pacific: Santa 

Catalina Island and San Clemente Island (California Channel 

Islands); Islas Los Coronados and Isla Guadalupe to Punta Malarrimo (Baja California); Bahía Magdalena (Baja California 

Sur); Islas San Benito; Isla Cedros; Isla Socorro, Isla Clarión 

and Isla San Benedicto (Islas Revillagigedo); Rocas Alijos; El 
NUMBER 96 • 145

Salvador; Costa Rica; Panama; Colombia; Ecuador; Galápagos 

Islands; Rapa Nui (Easter Island; Isla de Pascua). Central Pacific: Hawaiian Islands. Western Pacific: China; Korea; Japan.

Type Locality. Near Alexandria, Mediterranean 

Sea, Egypt.

Remarks. Since the accounts of Setchell and Gardner (1924, as Asparagopsis sanfordiana f. amplissima) and 

Dawson (1944a, as “A. sanfordiana”), the Gulf of California 

material has been referred to a broadly defined A. taxiformis

(Dawson, 1953a), a reportedly widespread, warm-temperate to 

FIGURE 63. Asparagopsis taxiformis: A. Habit, plumose gametophyte attached by basal stolons with rhizoids (JN-3113, US Alg. Coll.-158607). 

B. Close-up of ultimate branchlets, showing central axial filament surrounded by 3 pericentral cells, branchlets tapering to acute apex (JN-4822, 

US Alg. Coll. microscope slide 4975). 
146 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

tropical species. More recently, Ní Chualáin et al. (2004) found 

two clades of “A. taxiformis” that either represent cryptic sibling 

species or could possibly be considered as geographically isolated subspecies. Another Asparagopsis collected in San Diego, 

California, was determined to be A. armata Harvey (1855), a 

species described from Western Australia that probably was recently introduced (Ní Chualáin et al., 2004; Miller et al., 2011).

Further study of the northern Gulf specimens referred to 

A. taxiformis is needed to verify their identification. Molecular 

analyses should be undertaken to compare the northern Gulf 

material with type locality specimens of the southern Gulf A. 

sanfordiana f. amplissima Setchell et N. L. Gardner (1924: type 

locality: Eureka, Baja California Sur) and the Western Australian 

species, A. armata Harvey and A. sanfordiana Harvey, to evaluate their phylogenetic relationships.

Falkenbergia-Phase of Asparagopsis

FIGURE 64

Falkenbergia F. Schmitz in Schmitz and Falkenberg, 1897:479.

Sporophyte: small filamentous tufts, 0.3–0.5(–1.0) cm long; 

of ecorticate, terete filaments; branching irregular; attached by 

ventral, branched, multicellular holdfasts along various places 

on the thallus. Growth by a prominent apical cell that initially 

divides transversely, then lengthwise, to produce 3 pericentral 

cells surrounding each slender axial filament cell (and of similar 

length); trisiphonous axes 15–60(–75) μm in diameter; pericentral cells (35–57 μm long and 20–35 μm in diameter). Pericentral 

cells alternating in position from one segment to the next (spiral). 

Branches divaricate, developing from middle portion of pericentral cells. Highly refractive small cellular inclusions (gland cells)

often conspicuous in live material.

Tetrasporangia cruciately to irregularly divided; single, or 

in short series, one per segment; derived from a pericentral cell.

Habitat. Usually entangled among turf algae or occasionally epiphytic on Sargassum and other large algae; low intertidal to shallow subtidal.

Distribution. Falkenbergia hillebrandii-phase. 

Gulf of California: Puerto Peñasco to Cabeza Ballena; Jalisco. 

Eastern Pacific: Santa Catalina Island (California Channel 

Islands; Abbott and Hollenberg, 1976); Islas Todos Santos 

(R. Aguilar-Rosas et al., 1990) and Isla Guadalupe, Baja California (Setchell and Gardner, 1930) to Bahía Magdalena, Baja California Sur (Sánchez-Rodríguez et al., 1989); Isla Socorro (Islas 

Revillagigedo); Costa Rica (Bernecker, 2009).

Type Locality. Falkenbergia hillebrandii (Bornet in 

Ardissone) Falkenberg (1901; =Polysiphonia hillebrandii Bornet 

in Ardissone, 1883): Elba Island, Tuscan Archipelago, Tyrrhenian Sea, off northwest coast of Italy.

Remarks. Originally described as a separate genus 

on the basis of its very different morphology, culture studies 

of Falkenbergia have recognized it to be the sporophyte in the 

heteromorphic life history of Asparagopsis (Feldmann and Feldmann, 1939a, 1939b, 1943; Chihara, 1960, 1961). On the basis 

of nomenclatural priority, Falkenbergia was placed in synonymy 

with Asparagopsis.

Bonnemaisonia C. Agardh

Bonnemaisonia C. Agardh, 1822:196.

Gametophytes are erect with terete to slightly compressed 

axes, branches are bilateral, distichous or spirally arranged. 

Thalli are attached by a discoid holdfast, or they can be entangled 

FIGURE 64. Falkenbergia-phase of Asparagopsis (sporophyte): A. 

Axes composed of a slender axial filament surrounded by 3 pericentral cells that alternate in position, one segment to the next, prostrate 

axes attached by multicellular holdfasts (JN-4438, US Alg. Coll. microscope slide 4292). B. Axes branch irregularly and tetrasporangia 

borne one per segment. C. Tetrasporangia derived from pericentral 

cells, in irregular series (B, C, JN-4758, US Alg. Coll. microscope 

slide 4295).
NUMBER 96 • 147

by modified hook-like branchlets to various other algae. Each 

branch has opposite branchlets of two types. A short, simple to 

spinose branch occurs on one side, opposed on the other side by 

a long branch which rebranches, these are regularly alternate in 

successive pairs. This pattern may be obscured in some species. 

A single axial filament is evident throughout the thallus, each 

axial filament cell is associated with two opposite periaxial cells. 

These further divide outwardly to form the branchlets and develop additional cells that form the cortex. Refractive vesicular 

cells (gland cells) are present in the outermost cortex.

Tetrasporangia are produced by a heteromorphic sporophyte 

in most species, either the erect filamentous Trailliella-phase or a 

prostrate single-layered crust (Salvador et al., 2008). In “Trailliella,” branching is irregular and variable; numerous small secretory (vesicular) cells are borne laterally between adjacent filament 

cells. The crustose Hymenoclonium-phase is formed by frequently 

branching and anastomosing uniseriate filaments that are appressed 

to the substrate. Gametophytes are monoecious or dioecious. The 

carpogonial branch is 3-celled. Urn-shaped cystocarps, with an 

ostiolate pericarp, are on short branchlets. Spermatangia in dense 

outer layer on ovoid to elongated heads on short stalked branchlets. 

Remarks. The morphologically different, filamentous 

Trailliella Batters (1896) has long been recognized to be the sporophyte in the life history of Bonnemaisonia hamifera Hariot (Feldmann and Feldmann, 1939b, 1943; Harder, 1948; Harder and 

Koch, 1949; Koch, 1950; Dixon, 1959; Chihara, 1961; Kornmann 

and Sahling, 1962; Chen et al., 1969) and B. californica Buffham 

(1896) (Chihara, 1965, as “B. nootkana”). A crustose tetrasporophyte, Hymenoclonium serpens (H. Crouan et P. Crouan) Batters (1895), has been interpreted to be the alternate life history 

phase of two other species (Salvador et al., 2008), B. asparagopsis

(Woodward) C. Agardh (1822) (Feldmann and Feldmann, 1939b, 

1941, 1943) and B. clavata Hamel (1930) (Feldmann and Feldmann, 1939b, 1943; Cortel-Breeman, 1975) (however, this crust 

has also been suggested to be the juvenile gametophyte; see Kylin, 

1945; Feldmann, 1966). Interestingly, in another species, the alternate phase in the life history of the gametophyte of B. geniculata

N. L. Gardner (1927c) was found to be a morphologically similar tetrasporophyte (Shevlin and Polanshek, 1978). These culture 

studies suggest that Bonnemaisonia is a single genus with diverse 

life histories or that the genus may be polyphyletic, that is, it includes species that may belong in other genera.

Secondary natural products and their halogenated chemistries have been described in species of Bonnemaisonia (McConnell and Fenical, 1977b, 1980; Young et al., 1981). Antimicrobial 

activity was shown for secondary metabolites from members of 

the family (McConnell and Fenical, 1979). 

There is one species, Bonnemaisonia hamifera, reported 

in the northern Gulf of California, but so far, only the gametophytes have been found.

Bonnemaisonia hamifera Hariot

FIGURE 65

Bonnemaisonia hamifera Hariot, 1891:223; Dawson, 1953a:55, pl. 18: 

fig. 1; 1961b:407; Chihara, 1961:125, figs. 1–10; 1962:40–51, tbl. 2; 

1970:63, pl. 32: fig. 3; Norris and Bucher, 1976:8, fig. 6a; Abbott and 

Hollenberg, 1976:338, figs. 279, 281; Pacheco-Ruíz and Aguilar-Rosas, 

1984:71, 76; Stewart, 1991:68; Perestenko, 1996:82, pl. 45: fig. 3; 

González-González et al., 1996:176; Yoshida, 1998:649, fig. 3-41D,E; 

Pacheco-Ruíz and Zertuche-González, 2002:467; Pacheco-Ruíz et al., 

2008:207; Y.-P. Lee, 2008:230, figs. A–C.

Asparagopsis hamifera (Hariot) Okamura, 1921c:131,144, pl. 183: figs. 10, 

11, pl. 184: figs. 10–16; 1936:430, fig. 200; Kylin, 1941:6; Dawson, 

1945c:65; González-González et al., 1996:175.

Bonnemaisonia intricata P. C. Silva, 1957b:143.

Acrosymphyton caribaeum sensu Norris, 1973:10, pl. 2; Pacheco-Ruíz et 

al., 2008:207 [non Acrosymphyton caribaeum (J. Agardh) Sjöstedt, 

1926:9; basionym: Calosiphonia caribaeum J. Agardh, 1899:84].

Gametophytes entangled or epiphytic, up to 20 cm long; of 

a cylindrical main axis up to 2 mm in diameter, usually without 

or with few branches in lower portion and plumose in upper portions, with branches opposite but this mostly obscured, appearing spiral to irregular in arrangement. Branches with numerous, 

terete, short branchlets, up to 2 mm long, 100–150 μm in diameter, and occasional large, specialized, hamate (hook-shaped) 

branchlets, up to 1.0 cm long by up to 2 mm in diameter. Medulla a central axial filament surrounded by space and 2–3 layers 

of large globose cells of inner cortex. Outermost cortex a layer of 

smaller irregularly ovoid cells, about 10–25 μm in diameter, with 

numerous vesicular cells.

Cystocarps ellipsoid, 520 μm tall and 400 μm wide, with 

an ostiolate pericarp; borne terminal on a short, simple stalk. 

Spermatangial heads clavate to ovoid, 390–650 μm long and 

240–300 μm wide; spermatangia elongate-ovoid, in dense surface layer covering entire branchlet except short stalk.

Habitat. Epiphytic and/or entangled on various 

algae and rarely on gorgonians; low intertidal to subtidal, down 

to depths of 4.0–20 m.

Distribution. Gulf of California: Puerto Calamajue to Bahía de Los Ángeles; Roca Blanca, Puerto Refugio (Isla 

Ángel de la Guarda). Eastern Pacific: Goleta (southern California) and California Channel Islands to Cabo San Quintín (northern Baja California). Western Pacific: Russia; Korea; Japan.

Type Locality. Yokosuka, Kanagawa Prefecture, 

southeast Honshū, Japan.

Remarks. Spermatangial fragment, collected from 

Puerto Calamajue (JN-4637a; US Alg. Coll. microscope slide 5165), 

indicate the northern Gulf Bonnemaisonia hamifera may be dioecious. Culture studies of B. hamifera by Feldmann and Feldman 

(1939b, 1943) and Chihara (1961) found the sporophyte to be the 

morphologically distinct “Trailliella intricata.” Although the sporophyte of Gulf B. hamifera is presumed to be a “Trailliella,” it has 

not yet been encountered in the Gulf of California. The Trailliellaphase of B. hamifera can be distinguished from similar-looking filamentous tetrasporophytes of other Bonnemaisonia species by the 

small wedge-shaped vesicular cells that alternate from side to side 

or are irregular along the uniseriate filaments (Guiry and Guiry, 

2008–2010; for a description of T. intricata Batters (1896) as reported from Alaska to San Quintín, Baja California, see Dawson, 

1953a:56, and Abbott and Hollenberg, 1976:338, fig. 281).
148 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 65. Bonnemaisonia hamifera: A. Habit (gametophyte) with hook-shaped branchlets for entangling attachment (JN-5438, US Alg. 

Coll.-158653). B. Branch with developing and young cystocarps terminating short branches (JN-2989, US Alg. Coll. microscope slide 4277). C. 

Close-up of a hook branchlet (from A; JN-5438). D. Ultimate branchlet showing central axial filament surrounded by cortical cells, tapering to 

acute apex (JN-2989, US Alg. Coll. microscope slide 4277).
NUMBER 96 • 149

Ceramiales*

Ceramiales Oltmanns, 1904:683.

Members are erect or prostrate or prostrate with erect 

portions and range from minute uniseriate filaments to polysiphonous axes, foliose blades, to large and pseudoparenchymatous thalli. Members may be simple or lavishly branched, with 

branches terete to flattened, from radially to distichously or dorsiventrally organized. Growth is initially uniaxial and terminal, 

but in some members, with age, growth becomes diffuse from 

marginal or intercalary meristems. Axial cells producing 2–20 

(or more) periaxial or pericentral cells, in whorls or with single 

uniseriate determinate branches. Members may be ecorticate or 

partially to wholly corticated and may have a filamentous, rhizoidal, or pseudoparenchymatous cortex overlying axial cells. 

Trichoblasts are present or absent. Cells are uninucleate or 

multinucleate.

Life histories are triphasic, with isomorphic gametophytes 

and tetrasporophytes. Gametophytes of most members are dioecious, but some are monoecious. Carpogonial branches are 

generally four-celled. Formation of the auxiliary cell is directly 

from the supporting cell after fertilization. Carposporophytes 

are usually surrounded by involucral filaments or pseudoparenchymatous pericarp and are rarely naked. Spermatangia are in 

branched clusters, superficial sori, or stichidia. Tetrasporangia 

(or rarely polysporangia or monosporangia) are borne singly, in 

clusters, in sori, or in stichidia, on the whorl branches or determinate laterals. Tetrasporangia are tetrahedrally or cruciately/

decussately divided.

The Ceramiales is represented by eight families in the northern Gulf of California and includes a large percentage of the 

genera (about 29%) and species (about 27%) of the red algal 

subphylum Eurhodophytina that occur in the northern Gulf. 

Some of these are among the most attractive of the Gulf’s species.

KEY TO FAMILIES OF CERAMIALES IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli narrow to broad foliose blades (flattened), with 2–4 pericentral cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

1b. Thalli monosiphonous filaments (axial cells without pericentral cells) or with polysiphonous axes (axial cells with pericentral cells), not generally bladelike . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2a. Algae generally narrow blades; tetrasporangia in two longitudinal rows . . . . . . . . . . . . . . . . . . . . . . . . Sarcomeniaceae

2b. Algae narrow to broad foliose blades; tetrasporangia not in two longitudinal rows, produced in sori on blades in a single 

layer or in 2 irregular layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Delesseriaceae

3a. Algae monosiphonous filaments, with or without cortication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3b. Algae with polysiphonous axes (axial cell surrounded by pericentral cells); with monosiphonous or polysiphonous determinate branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Axes bearing persistent pigmented determinate pseudolaterals; spermatangia in stichidia-like branchlets of pseudolaterals

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dasyaceae

4b. Apices of axes often with colorless determinate branches (trichoblasts); spermatangia produced on branches of trichoblasts or on thallus surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rhodomelaceae

5a. Radially branched; indeterminate axes nearly fully corticated by alternating bands of short and long cells; determinate 

branches with narrow cortication bands only at the nodes; carposporophyte surrounded by nonostiolate pericarp . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spyridiaceae

5b. Variously branched, cortication not as above or ecorticate; carposporophyte without a surrounding consolidated pericarp . . . 6

6a. Procarp borne from the lower side of a basal cell of a determinate whorl branch or indeterminate branch; gland cells often 

present; tetrasporangia decussate–cruciate, cruciate, or tetrahedrally divided . . . . . . . . . . . . . . . . . . . . . . . Ceramiaceae

6b. Procarp formed from a periaxial cell of a fertile axial cell, gland cells generally absent; tetrasporangia tetrahedrally or 

polyhedrally divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

7a. Multicellular fusion cell present in cystocarp of most tribes; each axial cell with 1–6 whorl branches or determinate 

branchlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wrangeliaceae

7b. Cystocarp without multicellular fusion cell in most members; each axial cell with 1–4 whorl branches or determinate 

branchlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Callithamniaceae

Callithamniaceae

Callithamniaceae Kützing, 1843:370.

Thalli monosiphonous filaments, usually erect, axial cells 

bearing determinate branches or 1–4 whorl branches. Gland 

cells usually absent. 

Gametophytes usually dioecious. Spermatangia at ends of 

whorl branchlets or spermatangial filaments adaxial on cells of the 

determinate lateral branches (in patches, “tufts,” or continuous 

along cell). Procarp formed from a periaxial cell of a fertile axial cell 

of an indeterminate axis. This periaxial cell becomes the support 

cell for the carpogonial branch and lacks a sterile cell or sterile cell 

group. Carpogonial branches 4-celled, abaxial on the lateral side of 

the support cell (fertile periaxial cell/basal cell of whorl branchlet 

or determinate branch). Cystocarps naked or surrounded by loose 

* Contributed by Katina E. Bucher and James N. Norris. K. E. Bucher: 

Department of Botany, National Museum of Natural History, 

Smithsonian Institution, Washington, D.C. 20013-7012, USA.
150 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

involucral filaments arising from cells below the procarp. Meiosporangia are tetrahedrally or polyhedrally (rarely octahedrally) divided, sessile on cells of the whorl branches or determinate laterals. 

Four genera of the Callithamniaceae occur in the northern 

Gulf of California.

KEY TO THE GENERA OF THE CALLITHAMNIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Axes with 1 lateral branch per axial cell, alternately placed; determinate branches branched or unbranched . . . . . . . . 2

1b. Axes with 3(–4) determinate branches whorled about an axial cell; determinate branches branched . . . . . . . . . . . . . . 3

2a. Cells of thallus uninucleate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Aglaothamnion

2b. Cells of thallus multinucleate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Callithamnion

3a. Whorl branches subdichotomous, trichotomous, or quadrichotomously branched, or a mixture of all 3 types; new indeterminate axes forming chains 10–15 cells long before initiating whorl branches; thallus may be mucilaginous or lightly 

calcified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Crouania

3b. Whorl branches subdichotomously branched; new indeterminate axes forming chains 5–7 cells long before initiating 

whorl branches; not mucilaginous nor lightly calcified . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Crouanophycus

Callithamniaceae tribus Callithamnieae

Callithamniaceae tribus Callithamnieae F. Schmitz, 1889:450; Hommersand 

et al., 2005:207.

The tribe Callithamnieae is represented by two genera in the 

northern Gulf of California.

Aglaothamnion Feldmann-Mazoyer 

Aglaothamnion Feldmann-Mazoyer, 1940:451.

Algae are uniseriate branched filaments that are either (1) 

erect, tufted, and epiphytic, (2) partly endophytic in other algae, 

or (3), free-living and attached by basal discs or rhizoids issued 

from the base and the nodes of lowermost portions. Most members are uncorticated, but some are partially corticated by descending rhizoidal filaments. The axial cells produce one lateral 

branch per cell, resulting in a spiral or radial, alternate-distichous, 

or pseudodichotomous pattern. Determinate lateral branches are 

alternately, secundly, or subdichotomously branched. Cells are 

uninucleate with several discoid to band-shaped plastids.

Tetrasporangia are produced singly or in pairs and are usually sessile, on the adaxial side of the lateral branchlets, tetrahedrally to irregularly divided. Propagules have been reported in 

both sporophytic and gametophytic thalli of at least one species 

(Aponte et al., 1994). Procarps are borne in the upper portions 

of the indeterminate axes. Two opposite periaxial cells develop 

on an axial cell; only 1 bears a 4-celled carpogonial branch. After 

fertilization, an auxiliary cell is cut off from each of the opposite 

periaxial cells, which then develop the paired carposporophytes, 

composed of gonimolobes that are irregular, lobed, cordate, or 

reniform in shape. Most mature gonimoblast cells develop into 

carposporangia. Spermatangia are in clusters, borne on short 

spermatangial branchlets (usually one to three cells long) along 

the adaxial side of determinate laterals. The nucleus in the spermantangia is medial, with a mucilaginous vesicle above and 

below it.

Remarks. Vegetatively similar in most respects 

to Callithamnion, Aglaothamnion is characterized by having species with only uninucleate cells and irregular or lobed 

gonimolobes in the carposporophyte, whereas species of Callithamnion differ in having only multinucleate cells and generally spherically shaped gonimolobes. Harris (1962) reported 

finding overlapping reproductive characters in some of the uninucleate and multinucleate species and merged the two genera, 

a conclusion followed by Dixon and Price (1981) and Spencer et 

al. (1981). However, others (e.g., Itono, 1971b; Abbott, 1972, 

1999; L’Hardy-Halos, 1984; Aponte et al., 1994, 1997; Silva 

et al., 1996a) continue to separate Aglaothamnion and Callithamnion, using the nuclear condition as a valid character for 

generic distinction (see also L’Hardy-Halos and Rueness, 1990; 

Maggs et al., 1991; Maggs and Hommersand, 1993; Maggs and 

L’Hardy-Halos, 1993).

One species of Aglaothamnion is found in the northern Gulf 

of California.

Aglaothamnion endovagum (Setchell et N. L. Gardner) I. A. 

Abbott

Callithamnion endovagum Setchell et N. L. Gardner, 1924:771, pl. 28: fig. 

62; Kylin, 1941:28, fig. 6B; Dawson, 1944a:312; 1945d:56 (as Callithamnion sp.); 1961b:443; 1962a:29, pl. 8: fig.5; 1966b:65.

Aglaothamnion endovagum (Setchell et N. L. Gardner) I. A. Abbott, 

1972:262, fig. 7; Abbott and Hollenberg, 1976:617, fig. 559; Stewart, 

1991:123; González-González et al., 1996:169.

Acrochaetium grateloupiae E. Y. Dawson, 1950b:153, figs. 22, 23.

Thalli partly endophytic in red algae; endophytic filaments 

rarely branched, growing intercellularly between the cortical 

cells of the host, creeping irregularly parallel to the host’s thallus surface. Erect portions up to 250 μm tall, rarely with lateral 

branches; branches, when present, irregularly opposite, alternate, or unilateral. Axial cells up to 20 μm diameter at base, 

7–13 μm wide above, with blunt tips.

Tetrasporangia ovoid, 15–18(–23) μm diameter, 23–30 μm 

long, tetrahedrally divided, sessile, borne on main axis at position of lateral branchlets or rarely terminal. Procarps frequent, 

alternate along upper axes, and mature gonimoblasts irregularly 

globular, involucre lacking. Cystocarps appear “twinned” as 

they originate from auxiliary cells on a pair of opposite periaxial 

cells. Spermatangia unknown.
NUMBER 96 • 151

Habitat. Endo-epiphytic in blade-like red algae, particularly species of Grateloupia; intertidal to shallow subtidal.

Distribution. Gulf of California: Isla San Esteban; 

Bahía Catalina (at head of inlet to Canal de Guaymas) and Bahía 

Bocochibampo (west of Heroica Guaymas); Isla San Ildefonso. 

Eastern Pacific: southern California.

Type Locality. In fronds of Grateloupia prolongata; Isla San Esteban, Islas de la Cintura, Gulf of California, 

Mexico.

Remarks. Although Aglaothamnion endovagum 

has also been reported from Washington to Oregon, Scagel et 

al. (1989) noted that its presence in the northeastern Pacific required reinvestigation.

Callithamnion Lyngbye

Callithamnion Lyngbye, 1819:xxxi, 123.

Thalli mostly erect, monosiphonous filaments, ranging from 

uncorticated, corticated basally by a few descending filaments, 

to densely rhizoidally corticated. Main axes and major laterals 

bearing determinate branchlets, 1 per cell, alternately branched. 

Main branches multifariously, spirally, or distichously arranged. 

Secondary laterals unbranched or alternately or unilaterally 

branched. Attached to substratum by short branching rhizoids issued from lower cells of main axes, and slender long rhizoids from 

the basal cells of primary lateral branches that entwine and descend down the main axes. Cells multinucleate; gland cells absent.

Tetrasporangia tetrahedrally divided, usually sessile; single 

or in pairs, adaxial on cells of the ultimate determinate branchlets. A few species produce bisporangia (e.g., C. bisporum var. 

australe). Gametophytes are usually dioecious. Procarps formed 

near apex of indeterminate axis, one periaxial cell of a pair functioning as the support cell for a 4-celled carpogonial branch. 

Twin carposporophytes develop from auxiliary cells borne on 

each periaxial cell of the pair. Carposporophytes may lack involucres, or if present, issued from cells below the procarp. Spermatangia form short, dense, colorless tufts on the adaxial side of 

ultimate branchlets, or encircle it.

Five species of Callithamnion are reported in the northern 

Gulf of California. 

KEY TO THE SPECIES OF CALLITHAMNION IN THE NORTHERN GULF OF CALIFORNIA

1a. Sporangia divide once, forming bisporangia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. bisporum var. australe

1b. Sporangia divide twice, forming tetrahedrally divided tetrasporangia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Branching alternate, predominantly distichous, at least in middle and upper parts, or tending to be distichous rather than 

multifariously arranged . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2b. Branching alternate, and predominantly radially or spirally (multifarious) arranged throughout . . . . . . . . . . . . . . . . . 3

3a. Attenuating considerably upward from base (170–300 μm in diameter basally) to tips (8–10 μm in diameter); densely 

branched above . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. ramosissimum

3b. Not as markedly attenuated as above, ultimate branches 0.25 the diameter of main axes; openly branched above . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. marshallense

4a. Branching to 3 orders; ultimate branchlets relatively sturdy, 40–50 μm in diameter (about 0.5 the diameter of main axes); 

apices initially incurved, becoming recurved (but not forcipate) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. rupicola

4b. Branching to 4–5 orders; ultimate branchlets slender, 15–20 μm in diameter (0.1–0.3 the diameter of main axes); often 

somewhat corymbose; apices only more or less incurved . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. paschale

Callithamnion bisporum var. australe E. Y. Dawson

FIGURE 66

Callithamnion bisporum var. australe E. Y. Dawson, 1962a:26, pl. 9: fig.4; 

1966b:65; González-González et al., 1996:181; Pacheco-Ruíz and 

Zertuche-González, 2002:468; Pacheco-Ruíz et al., 2008:211. 

Algae of few erect axes, up to 1.0 cm tall, branching alternately from distal end of axial cells, up to 4 orders; attached by 

multicellular rhizoids. Branches tending to be spirally arranged in 

lower portions and distichous above; middle portions often without branches for 8–12 cells. Cells to 200 μm in diameter in basal 

portion of thallus;1.2–1.5 times longer than diameter, gradually 

attenuating upward; middle portions with cells 4–6 times longer 

than wide; upper portions 3–5 times longer than diameter; ultimate branchlets somewhat adaxially curved, of 4–8 smaller cells, 

10–15 μm in diameter, with blunt apices. Gland cells absent.

Sporangia once divided to form elliptical bispores, 50 μm 

tall, 30 μm in diameter; sessile, usually single, sometimes 2 on 

cell. Gametangial thalli unknown. 

Habitat. Shallow subtidal, 6–18 m depths.

Distribution. Gulf of California: Bahía de Los 

Ángeles; Punta Concepción to Puerto Escondido.

Type Locality. Dredged from 6–9 m depths; outer 

bay, Puerto Escondido, Baja California Sur, Gulf of California, 

Mexico.

Remarks. Besides its markedly disjunct distribution, 

the Gulf of California endemic variety Callithamnion bisporum

var. australe differs in having longer ultimate branchlets and 

smaller bisporangia than those of the northeastern Pacific C. bisporum N. L. Gardner (1927e) var. bisporum from Puget Sound, 

Washington (Scagel et al., 1989).

Callithamnion marshallense E. Y. Dawson

Callithamnion marshallense E. Y. Dawson, 1957b:117, fig. 25a–c; 1960a:50; 

1961b:443; 1962a:31, pl. 10: figs. 1–3; Huerta-Múzquiz and MendozaGonzález, 1985:52; González-González et al., 1996:181; Bernecker, 

2009:CD-Rom p. 63; Fernández-García et al., 2011:60.
152 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Thalli in loose tufts, 4–5 mm tall; main axes of noncorticated cells, up to 80–90 μm in diameter, 80–135 μm long; lower 

portions partially prostrate, basally attached by modified lateral 

branchlets with terminal discs (some attachment branchlets of 

catenate cells, with a few descending rhizoidal filaments; see 

Dawson, 1962a, pl. 10: fig. 3). Axes alternately branched, but 

not always from every cell, branchlets usually spirally arranged, 

often at about 1

⁄5 divergence, sometimes tending in part to be 

distichous; branching often becoming more open above; ultimate 

branchlets, mostly simple, lax and curved, 20–30 μm in diameter, long, slightly attenuate, with blunt apices.

Tetrasporangia subspherical, about 40 μm in diameter; sessile, 1 to several on adaxial side of lower half of lateral branchlets. Cystocarps and spermatangia not known.

Habitat. On rocks or shells (also can be epiphytic; 

Dawson, 1962a) in tide pools; intertidal.

Distribution. Gulf of California: Punta Pelícano 

(vicinity of Puerto Peñasco); Bahía de La Paz. Eastern Pacific: 

Punta Santa Rosaliita (“Punta Santa Rosalía”), Baja California to 

Laguna de San Ignacio, Baja California Sur; Costa Rica; Panama.

Type Locality. On shells and coral rubble, 1.6–3.0 

m depths; lagoon, south end of Parry Island, Enewetak Atoll 

(Eniwetok), Marshall Islands.

Remarks. A single specimen from Punta Pelícano in 

the upper Gulf of California (JN-4234, US Alg. Coll. microscope 

slide 4684) seems close to Callithamnion marshallense and is 

tentatively referred to this species.

Callithamnion paschale Børgesen

Callithamnion paschale Børgesen, 1924:294, fig. 35a–d; Dawson, 1959a:28, 

fig. 6b; 1961b:443; 1962a:31, pl. 9: figs. 5, 6; 1966a:26; Abbott 

and Hollenberg, 1976:613, fig. 555; Huerta-Múzquiz, 1978:338; 

Mendoza-González and Mateo-Cid, 1985:26; Santelices and Abbott, 

1987:9; Ramírez and Santelices, 1991:314; Mateo-Cid et al., 1993:48; 

González-González et al., 1996:181; Anaya-Reyna and RiosmenaRodríguez, 1996:864, tbl. 1; Mendoza-González and Mateo-Cid, 

1996b:67, pl. 7: figs. 26–28, pl. 8: figs. 29–32; Riosmena-Rodríguez et 

al., 1998:26; L. Aguilar-Rosas et al., 2000:131; CONANP, 2002:138; 

Pacheco-Ruíz and Zertuche-González, 2002:468; Mateo-Cid et al., 

2006:56; Dreckmann et al., 2006:155; Serviere-Zaragoza et al., 2007:9; 

Pacheco-Ruíz et al., 2008:211.

Callithamnion veleroae E. Y. Dawson, 1944a:312, pl. 50: figs. 3–5; GonzálezGonzález et al., 1996:182.

Algae forming tufts, up to 2.5 cm tall; axes basally to 150 

μm in diameter, uncorticated, branched alternately; upper portions often corymbose, dense with branches; upper branchlets 

of 4–5 orders; ultimate branchlets of up to 15 cells, 6–13(–20) 

μm in diameter; attached by broad basal cells on other algae (or 

occasionally with some descending rhizoidal filaments basally). 

Branches gradually becoming shorter upward; branching of last 

2–3 orders usually distichous; lower orders of branches distichous or irregularly multifarious.

Tetrasporangia elliptical, 45–60 μm long, 45–55 μm in diameter, solitary and sessile, adaxial on upper branchlets. Carposporophytes without involucres; usually in pairs, in upper 

portions of indeterminate axes; each nearly spherical, about 130 

μm in diameter. Spermatangia in tufted clusters, adaxial on ultimate branchlets.

Habitat. Usually epiphytic on other algae; mid intertidal to shallow subtidal, down to 2 m depths (also dredged from 

22 and 40 m depths; Dawson, 1962a).

Distribution. Gulf of California: Playa Tucson, 

Bahía La Choya (Bahía Cholla) to Playa Las Conchas (Playa 

Estación), Puerto Peñasco to Puertecitos; Puerto Refugio, Isla 

Ángel de la Guarda to Isla Partida Norte (Islas de la Cintura); 

Bahía Tepoca to Isla Patos (off N end of Isla Tiburón); Bahía Bocochibampo to Punta Los Frailes. Eastern Pacific: San Clemente 

Island and Santa Catalina Island (California Channel Islands); 

Isla San Benedicto (Islas Revillagigedo); Chiapas; Rapa Nui (Easter Island; Isla de Pascua).

Type Locality. Hanga Piko, Rapa Nui (Easter Island; Isla de Pascua), Valparaíso Region, Chile.

Callithamnion ramosissimum N. L. Gardner

Callithamnion ramosissimum N. L. Gardner, 1927e:404, pl. 86; Dawson, 1945d:56; 1961b:443; 1962a:32, pl. 10: figs. 6, 7; Schnetter 

and Bula-Meyer, 1982:159, pl. 29: fig. C; Stewart and Stewart, 

1984:145; Huerta-Múzquiz and Mendoza-González, 1985:52; 

FIGURE 66. Callithamnion bisporum var. australe: Upper portion 

of thallus with bisporangia (isotype, EYD-7190, US Alg. Coll. microscope slide 333).
NUMBER 96 • 153

Stewart, 1991:126; González-González et al., 1996:181; CONANP, 

2002:138.

Algae small, mostly 8–12 mm high, principal axes 170–300 

μm in diameter at the base; uncorticated or with a few descending filaments. Abundantly branched above, branching alternate 

and multifarious; ultimate branchlets slender, of 6–10 cells, 

attenuating to 10 μm in diameter or less, 2–5 diameters long, 

curved up and inward; with blunt apices.

Tetrasporangia ellipsoidal, 50–65 μm long (including thick 

envelope), sessile, and borne adaxially in a series (2–4) on 

branchlets in upper portion of thallus. Cystocarps unknown. 

Spermatangia forming dense tufts on the adaxial side of ultimate 

branchlets.

Habitat. Lowermost intertidal or in tide pools, epiphytic on Sargassum and other large algae.

Distribution. Gulf of California: Puerto Peñasco; 

Bahía de Loreto to Bahía de La Paz. Eastern Pacific: Santa Catalina Island (California Channel Islands); La Jolla, southern 

California; Isla Guadalupe (off Baja California); Isla Gorgona, 

Colombia. Western Pacific: Vietnam (Nguyen et al., 2013).

Type Locality. Epiphytic on Hypnea; La Jolla, San 

Diego County, California, USA.

Remarks. Callithamnion ramosissimum is apparently rare in the northern Gulf of California. Dawson (1945d) 

noted C. ramosissimum was “infrequent and commonly overlooked,” and it was not treated in the California flora by Abbott 

and Hollenberg (1976). It has not been recently collected from 

the type locality in La Jolla (Stewart, 1991).

Callithamnion rupicola C. L. Anderson

Callithamnion rupicola C. L. Anderson, 1894:360, figs. A,B [as “C. 

rupicolum”]; Smith, 1944:319, pl. 81: fig. 3; Taylor, 1945:260 

“prox.”; Dawson, 1951:53; 1961b:443; 1962a:33, pl. 11: fig. 1; 

Abbott, 1971:354, fig. 2c; Abbott and Hollenberg, 1976:613, fig. 

557; Stewart and Stewart, 1984:145; Pacheco-Ruíz and AguilarRosas, 1984:73; Mendoza-González and Mateo-Cid, 1986:425; 

R. Aguilar-Rosas and Machado-Galindo, 1990:188; R. AguilarRosas et al., 1990:125; Stewart, 1991:127; R. Aguilar-Rosas and 

Aguilar-Rosas, 1994:523; Mateo-Cid and Mendoza-González, 

1994b:41; González-González et al., 1996:181; L. Aguilar-Rosas et 

al., 2000:131; CONANP, 2002:138.

Callithamnion breviramosum N. L. Gardner, 1927e:403, pl. 84; Dawson, 

1961b:442; 1962a:27, pl. 8: figs. 3, 4; Stewart and Stewart, 1984:145; 

Huerta-Múzquiz and Mendoza-González, 1985:52; GonzálezGonzález et al., 1996:181.

Callithamnion rigidum E. Y. Dawson, 1962a:33, pl. 10: figs. 4, 5; Stewart 

and Stewart, 1984:145; González-González et al., 1996:181.

Callithamnion uncinatum E. Y. Dawson, 1962a:35, pl. 11: fig. 4; GonzálezGonzález et al., 1996:182.

Callithamnion varispiralis E. Y. Dawson, 1949b:16, figs. 29, 30, 54; 

1954e:340; 1961b:443; González-González et al., 1996:182.

Algae in small tufts, mostly up to 10(–20) mm tall; of numerous uncorticated axes, 80–100(–150) μm in diameter, with 

cells 400–800 μm long in lower portions; cells becoming shorter 

above, to about 1 diameter long; axes abundantly, mainly 

distichously branched to 1–2 times pinnately, second-order 

branches mostly alternate but can become pinnately to bipinnately branched; ultimate branchlets, usually simple, coarse, 

sturdy (somewhat rigid), straight or recurved, with attenuated, 

rounded, blunt, or uncinate apices; attached by loose, uniseriate, multicellular rhizoids descending near base; rhizoids with or 

without digitate ends (basal descending rhizoids may entangle or 

coalesce, giving pseudocorticated-like appearance to basal portion of thallus).

Tetrasporangia subspherical to ellipsoidal, (45–)55–70 μm 

long, (26–)50–60 μm in diameter; sessile, adaxial on branchlets. 

Carposporophytes irregularly shaped, subterminal on main axes 

and branches. Spermatangia forming continuous clusters along 

adaxial side of lateral branchlets.

Habitat. Epiphytic on Codium, Gracilaria, and 

other algae or on rocks; low intertidal to shallow subtidal, down 

to 4 m depths.

Distribution. Gulf of California: Puertecitos to 

Bahia de Loreto; Guaymas. Eastern Pacific: northern California 

to Todos Santos, Baja California Sur; Islas Todos Santos (off 

Ensenada), Isla Guadalupe, Islas San Benito, and Isla Cedros, 

Baja California; Oaxaca; Colombia; Galápagos Islands.

Type Locality. On rocks; Monterey Bay, Monterey 

County, central California.

Remarks. Callithamnion rupicola as currently interpreted is a highly variable species (Abbott, 1971; Abbott and 

Hollenberg, 1976) that includes several species described from 

the eastern Pacific: C. varispiralis from Santa Catalina Island, 

California Channel Islands (Dawson, 1949b) to Bahía de Sebastián Vizcaíno, Baja California (Dawson, 1954e), C. breviramosum from La Jolla (Gardner, 1927c), C. rigidum from Isla 

Guadalupe, Baja California (Dawson, 1962a), and C. uncinatum

from Salina Cruz, Oaxaca (Dawson, 1962a).

The Gulf of California C. rupicola should be compared molecularly to C. rupicola specimens from the type locality of Monterey Bay, California, and the other species that are considered 

conspecific to assess their phylogenetic relationships and confirm 

their taxonomic identities.

Callithamniaceae tribus Crouanieae

Callithamnion tribus Crouanieae F. Schmitz, 1889:451.

Two genera of the tribe Crouanieae are reported in the Gulf 

of California.

Crouania J. Agardh

Crouania J. Agardh, 1842:83.

Algae are erect, partially erect with prostrate axes or sometimes wholly prostrate, branching up to eight orders. Axes terete, 

and may be ecorticate or corticated by rhizoids, and some species 

are mucilaginous and/or lightly calcified. Thalli are composed 

of monosiphonous filaments, each axial cell bearing a whorl of 

three branched determinate branchlets and attached to the substratum by multicellular rhizoids issued from the basal cells of 
154 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

whorl branches and lower cells of the axial filament. Thalli are 

freely branched with lateral indeterminate branches replacing 

one of the branchlets in a whorl or adventitious indeterminate 

branches also developing from the basal cell of whorl branches. 

Indeterminate branch initials originating at irregular intervals, 

typically developing chains of 10–15 (or more) cells before initiating the whorl branches. Whorl branches are dichotomously, 

trichotomously, or occasionally quadrichotomously branched 

or frequently a combination of all three. Some of the whorl 

branches terminate in a hair cell. Gland cells are usually absent, 

but occasionally present in some species.

Tetrasporangia are sessile, subspherical to ovoid, tetrahedrally divided, and borne on the basal cell or proximal cells of 

whorl branches (except in C. pleonospora, where tetrasporangia are also borne on more distal cells). Gametophytes are dioecious. Procarps are borne in place of a determinate whorl branch 

near the apices of indeterminate axes. The carpogonial branch 

is four-celled on a supporting cell (fertile periaxial cell) that develops an auxiliary cell (after fertilization) that forms the carposporophyte. The carposporophyte consists of globose clusters of 

carposporangia without involucral filaments but is subtended by 

elongating whorl branches from axial cells below. Spermatangial 

parent cells are terminal on the ultimate cells of whorl branches, 

each bearing clusters of 2–3 spermatangia. 

There is one species of Crouania reported in the northern 

Gulf of California.

Crouania attenuata (C. Agardh) J. Agardh

FIGURE 67

Mesogloia attenuata C. Agardh, 1824:51. 

Crouania attenuata (C. Agardh) J. Agardh, 1842:83; Setchell and Gardner, 

1930:167; Dawson, 1952:431; 1957a:7; 1961b:438; 1962a:23, pl. 

7: fig. 4; Stewart and Stewart, 1984:145; Sánchez-Rodríguez et al., 

1989:44; González-González et al., 1996:307; Silva et al., 1996b:233; 

Abbott et al., 2002:306, fig. 13; Serviere-Zaragoza et al., 2007:9. 

Thalli soft and lax, erect up to 2(–3) cm tall, up to 250 μm 

in diameter, may be mucilaginous or lightly calcified. Axes ecorticate, irregularly branched up to 3 orders, with axes covered 

with short determinate whorl branches. Thalli attached by digitate discs at the ends of uniseriate, multicelluar rhizoids that are 

FIGURE 67. Crouania attenuata: A. Upper portion of erect axis. B. Mid-portion of branch showing much-branched whorl branches that are 

upturned toward branch apex. C. Whorl branches dichotomously, trichotomously, and quadrichotomously branched; whorl branches with 

elongate terminal cells (A–C, JN-4842, US Alg. Coll. microscope slide 4705). 
NUMBER 96 • 155

issued from the basal cells of lower whorl branches or prostrate 

axes. Each axial cell bears 3 compound whorl branches toward 

its distal end. Indeterminate lateral branches borne in place of a 

whorl branch; adventitious indeterminate laterals may develop 

from basal cell of whorl branches. Axial cells cylindrical, up to 

75(–90) μm in diameter in basal portions, thinner above; axial 

cell length about 2–3 times its diameter. Axes taper rapidly near 

apices. Branching of erect thallus monopodial at first, later becoming sympodial to ramisympodial, sometimes irregular. Determinate whorl branches repeatedly branched, up to 5 orders, the 

first-order to some of the third-order divisions trichotomous (occasionally quadrichotomous), higher-order divisions usually subdichotomous. The cells of the whorl branches are progressively 

smaller in diameter outward, basal cells obovoid, 7–18 μm in diameter, and outermost cells cylindrical and elongate, about 3 μm 

in diameter by 9 μm long, ultimate cells terminate in rounded tip, 

occasionally with a terminal hair cell. Mature whorl branches 

are 66–105(–150) μm long and curve upward toward apex of 

axes. Consecutive whorls may be widely separated from each 

other basally, whorls more crowded above, sometimes concealing axial cells.

Tetrasporangia subspherical to ovoid, tetrahedrally divided, 50–60 μm diameter (including thick wall), sessile on the 

upper side of basal cell of whorl branches. Procarps formed 

near apices, cystocarps with several rounded groups of carposporangia. Spermatangia about 2.0–4.5 μm in diameter, borne 

in clusters of (2–)3–5 on spermatangial parent cells at the tips 

of fertile whorl branches in the middle and upper portions of 

the thallus.

Habitat. Epiphytic on larger algae; intertidal to shallow subtidal, 8–28 m depths; also dredged from 47 m depth.

Distribution. Gulf of California: Puerto Peñasco 

to Puerto Libertad; Cabeza Ballena. Eastern Pacific: Isla Guadalupe (off Baja California); Punta Eugenia (“San Eugenio”) (Bahía 

Sebastián Vizcaíno) to Bahía Magdalena, Baja California Sur; 

Rocas Alijos (off Baja California Sur); Isla Clarión (Islas Revillagigedo); Chile; Rapa Nui (Easter Island; Isla de Pascua). Western 

Pacific: China; Japan; Korea; Vietnam.

Type Locality. “Atlantic Ocean” (Agardh, 1824); 

“probably Atlantic Coast of France” (Dawson, 1962a:24). Lectotype locality: Brittany, France (see Dixon, 1962:256).

Crouanophycus Athanasiadis

Crouanophycus Athanasiadis, 1998:517.

Crouaniella Athanasiadis, 1996a:196, nom. illeg. [a later homonym of 

Crouaniella (P. Saccardo) Lambotte, 1888:320].

Algae are composed of monosiphonous, ecorticate filaments, with erect and prostrate axes. Each axial cell bears 3 

determinate subequal whorl branches. The whorl branches are 

composed of elongate cells, with the periaxial cell being smaller, 

equal, or greater in size than the contiguous cells. Whorl branches 

are subdichotomously branched (up to fourth order), with divisions beginning at the periaxial cell, and their flat side toward 

the bearing axis. Indeterminate lateral branches are borne as a 

fourth branch in a whorl of determinate branches at irregular 

intervals. New indeterminate laterals form chains of 5–7 cells 

before initiating the whorl branches. Adventitious development 

of new indeterminate laterals from basal cells of whorl branches 

was not observed. Thalli are attached by multicellular rhizoids 

developed from axial cells in the basal region and from periaxial 

cells. Gland cells are lacking.

Tetrasporangia are spherical to oblongate, tetrahedrally 

divided, and sessile, usually borne singly, and adaxially on the 

basal cell of whorl branches (=periaxial cells). Procarps are unknown. Carposporophytes borne singly in the apical region of an 

axis (Athanasiadis, 1996a). Spermatangial structures are short 

branchlets issued by lower cells of the whorl branches, composed 

of a cell bearing a group of spermatangial parent cells that each 

produce one to several terminal spermatangia.

Remarks. In the generitype, Crouanophycus latiaxis

(I. A. Abbott) Athanasiadis (1998), proximal whorl branch cells 

issue single cells that bear several spermatangial parent cells, 

1–4(–6) that each produce 1–3 (typically a pair) terminal spermatangia (see Bucher and Norris, 1995: fig. 9, as Antithamnionella latiaxis I. A. Abbott, 1979). Spermatangia are borne in a 

manner similar to those of Scageliopsis E. M. Wollaston (Wollaston, 1981:178, fig. 10; Athanasiadis, 1996a:205).

There is one species of Crouanophycus in the Gulf of 

California.

Crouanophycus mcnabbii (E. Y. Dawson) Athanasiadis

FIGURE 68

Crouanophycus mcnabbii (E. Y. Dawson) Athanasiadis, 1998:517.

Antithamnion mcnabbii E. Y. Dawson, 1959a:28, fig. 7c; 1961b:439; 

1962a:18, pl. 5: fig. 4; González-González et al., 1996:174.

Antithamnionella mcnabbii (E. Y. Dawson) D. N. Young, 1981:97, figs. 3, 4.

Crouaniella mcnabbii (E. Y. Dawson) Athanasiadis, 1996a:199, figs. 107A–

C, 108A–C.

Algae monosiphonous filaments with prostrate and erect 

axes, up to 8 mm tall; with 3 subequal whorl branches from 

the distal end of axial cells, whorl branches closely spaced along 

axis; algae attached by rhizoids from axial cells in basal portions 

of erect axes and basal cells of whorl branches (periaxial cells). 

Axial cells in basal regions to 115 μm long by 60–75 μm in diameter, decreasing in size toward tips. Whorl branches subdichotomously branched, 3(–4) times, divisions starting after periaxial 

cell. Whorl branches short, 5–7 cells long and 80–130 μm in 

length. Basal cells of whorl branches equal or larger than contiguous branch cells, 30 μm long and 12 μm in diameter, cells 

decreasing in size outward, 8 μm long and 4.5 μm in diameter 

at blunt tips. Indeterminate laterals multifariously arranged, develop as a fourthlateral of a whorl, at irregular intervals, at every 

fourth to fifth (or more) axial cell. Gland cells absent.

Tetrasporangia subspherical to oblong, tetrahedrally divided, up to 50 μm long, 35 μm in diameter; borne singly, 

adaxially, and sessile on basal cell of whorl branches. Sexual reproduction unknown.
156 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 68. Crouanophycus mcnabbii: A. Upper portion of branched axis. B. Subdichotomously branched whorl branches. C. 

Tetrasporangia borne singly and sessile on basal cell of whorl branches. D. Habit of tetrasporangial axes (A–D, JN-3406, US 

Alg. Coll. microscope slide 4717). 
NUMBER 96 • 157

Habitat. On rocks, with other turf algae, and epiphytic on Dictyota; low intertidal to shallow subtidal, 1.0–9.5 

m depths.

Distribution. Gulf of California: Caleta Santa 

María (north of Puerto Santa Rosalía) to Roca El Solitario, Bahía 

Agua Verde. Eastern Pacific: Costa Rica; Galápagos Islands.

Type Locality. On rocks; Roca El Solitario, Bahía 

Agua Verde, Baja California Sur, Gulf of California, Mexico.

Remarks. Crouanophycus mcnabbii has also been 

reported in the western Pacific from southern Japan (Itono, 

1969, as “Antithamnion mcnabbii”); however, Itono (1977a) 

later considered the Japanese record to be doubtful. It has also 

been reported in India (Silva et al., 1996a, as “Antithamnionella 

mcnabbii”).

Ceramiaceae

Ceramiaceae Dumortier, 1822:71, 100.

Algae are monosiphonous filaments (uniaxial), with axial cells 

bearing one to many determinate laterals or whorl branches. Thalli 

are erect, decumbent, or prostrate, and many are uncorticated, 

although others may be wholly or partly corticated by rhizoidallike filaments or small-celled filaments. Cells are mostly uninucleate, and gland cells are often present.

Most produce tetrasporangia that are decussate-cruciately, 

cruciately, or, less commonly, tetrahedrally divided. Tetrasporangia are borne singly, clustered, or in whorls, sessile or pedicellate, and may be naked, involucred, or more or less covered by 

the cortex of ordinary branches. Gametophytes are dioecious or 

occasionally monoecious. Carpogonial branches are four-celled 

and borne abaxial on the lower lateral side of the supporting cell. 

After fertilization, an auxiliary cell is formed and cuts off a single 

gonimoblast initial. The carposporangia may be formed by all or 

most cells or only by the terminal cells of gonimoblast filaments. 

Cystocarps are composed of one to several gonimolobes and may 

be surrounded by sterile involucral filaments, flanked by one or 

more adventitious laterals, or naked. Multicellular fusion cells 

are absent. Spermatangia are terminal and either form colorless 

patches covering the cortex of portions of certain species or are 

borne terminally on specialized determinate branchlets.

There are nine genera of the Ceramiaceae represented in the 

marine flora of the northern Gulf of California. 

KEY TO THE GENERA OF THE CERAMIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Ultimate order of branches of axes usually uncorticated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Ultimate order of branches of axes incompletely or completely corticated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2a. Axial cells bearing opposite or whorled branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2b. Axial cells bearing zero or only 1 or 2 opposite branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Irtugovia

3a. Pair of opposite whorl branches per axial cell; periaxial cells at base of whorl branches smaller than adjacent cells . . . . 4

3b. One to 4(–5) whorl branches per axial cell; periaxial cells about the same size as contiguous cells in whorl branch . . . . 5

4a. Descending and ascending rhizoid-like filaments developing from periaxial cells, forming a loose to dense pseudoparenchymatous cortex around axial row; gland cells on basal cells of whorl-branches (periaxial cell) attached by thin cytoplasmic thread . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Balliella

4b. Rhizoids developing from periaxial cells not producing loose to dense pseudoparenchymatous cortex around axial row; 

gland cells on special short branchlets, bridging 2 cells of branchlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Antithamnion

5a. Whorl branches all of approximately equal length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Antithamnionella

5b. Whorls each with 2 opposite pairs; juxtapose pairs often of different lengths and different branching patterns . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pterothamnion

6a. Axes nearly or entirely covered by cortication, cortex composed predominately of basipetal filaments; basipetal corticating filaments with rectangular cells arranged in regular longitudinal rows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6b. Axes often with internodal space between nodal bands; if entirely corticated cortex not predominately composed of 

basipetal filaments; basipetal cortical cells more ovoid to angular and not typically arranged in regular longitudinal 

rows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

7a. Spines usually present, especially at apices; 3 cortical initials cut off per periaxial cell; tetrasporangia emergent from 

cortex; spermatangia borne at the nodes, produced terminally on branched monosiphonous filaments issued from the 

upper ends of periaxial cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Centroceras

7b. Spines absent or rare; 4 cortical initials cut off per periaxial cell; tetrasporangia entirely or partially embedded in cortex,

spermatangia cover cortical surface cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Corallophila

8a. Erect axes with alternate branching pattern; 3 cortical initials cut off per periaxial cell, the third being basipetally directed 

and divided off transversely, cell initially appearing horizontally elongated; rhizoids are unicellular and develop only from 

periaxial cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gayliella

8b. Axes subdichotomously or irregularly branched; (1–)3–5 cortical initials per periaxial cell; basipetal cells not horizontally 

elongated; rhizoids multicellular, developing from periaxial and inner and outer cortical cells . . . . . . . . . . . Ceramium
158 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Ceramiaceae tribus Antithamnieae

Ceramiaceae tribus Antithamnieae Hommersand, 1963:330.

One of the five genera of the tribe Antithamnieae is represented in the northern Gulf of California.

Antithamnion Nägeli

Antithamnion Nägeli, 1847:202.

Thalli are delicate, often epiphytic, and composed of erect 

axes that arise from prostrate axes or decumbent axes or occasionally are mostly prostrate. Axes are uniseriate, uncorticated, 

and bear an opposite pair of determinate whorl branches (or 

rarely 3 in some species) on the axial cells of erect axes. Whorl 

branches are distichously to decussately arranged along bearing axis and may be simple to variously branched, up to 4 orders. Each whorl branch has an isodiametric basal cell (periaxial 

cell) that is noticeably shorter than adjacent cells and lacks side 

branches, but may issue 1–3 rhizoids, an adventitious indeterminate branch, or carpogonial branch. New indeterminate branches 

occur in three situations depending on the species: (1) replacing 

1 whorl branch in a pair, (2) opposite whorl branch suppressed, 

with new indeterminate branch occurring alone on axial cell, or 

(3) new indeterminate branch issued from the basal cell of whorl 

branches. Gland cells are often present, borne laterally or terminally on modified short, 2–6(–9)-celled branchlets; each gland cell 

covers 2 to several cells. Vegetative cells are uninucleate.

Tetrasporangia are generally cruciately divided but sometimes may be irregularly divided and usually ovoid to oblong 

when mature. Tetrasporangia may be sessile or pedicellate and 

borne on the inner (proximal) cells of opposite whorl branches 

or often replacing branchlets of the final order. Gametophytes 

are usually dioecious, rarely monoecious. Carpogonial branches 

are 4-celled, borne singly on the basal cells of successive whorl 

branches near apices of indeterminate branches. Only one carposporophyte maturing per axis, borne near the apex of the fertile axis, naked or subtended by elongated whorl branches from 

the axial cell(s) below. Spermatangia clustered on spermatangial 

parent cells that are whorled about short-celled branchlets (cylindrical heads or clusters) that are usually borne adaxially on successive inner cells of whorl branches or second-order branchlets.

Remarks. Two species are reported in southern Gulf 

of California: Antithamnion antillanum Børgesen (1917) from 

north of Cabo Pulmo (Dawson, 1962a; as A. lherminieri), and A. 

hubbsii E. Y. Dawson (1962a) from Bahía de Loreto (CONANP, 

2002). Two other taxa originally described as species of Antithamnion from the southern Gulf are now recognized to belong 

in other genera: A. pseudocorticatum E. Y. Dawson (1962a) 

is now Balliella pseudocorticata (E. Y. Dawson) D. N. Young 

(1981), and A. mcnabbii E. Y. Dawson (1959a) is now Crouanophycus mcnabbii (E. Y. Dawson) Athanasiadis (1998). Another 

taxon, Antithamnion plumulum (Ellis et Solander) Thuret ex Le 

Jolis (1863) var. plumulum as reported from Isla Santa Cruz in 

the southern Gulf of California (Dawson, 1966b), should be reinvestigated. The Isla Guadalupe “A. plumulum var. plumulum” 

of Dawson (1962a) and Stewart and Stewart (1984), was noted 

by Athanasiadis (1996a:57) to probably be a species of Pterothamnion Nägeli.

There are three species of Antithamnion found in the northern Gulf of California.

KEY TO THE SPECIES OF ANTITHAMNION IN THE NORTHERN GULF OF CALIFORNIA

1a. Determinate whorl branches predominately alternately branched; tetrasporangia sessile . . . . . . . . . . . . . . . A. decipiens

1b. Determinate whorl branches predominately pectinate or secund; tetrasporangia usually pedicellate . . . . . . . . . . . . . . . 2

2a. Indeterminate branches borne singly on an axial cell, without an opposite determinate whorl branch; gland cells often on 

branchlet of 3 or more cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. defectum

2b. Indeterminate branches usually borne opposite a determinate whorl branch; gland cells often on short branchlet of 2(–3) 

cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. kylinii

Antithamnion decipiens (J. Agardh) Athanasiadis

FIGURE 69

Callithamnion decipiens J. Agardh, 1842:70.

Antithamnion decipiens (J. Agardh) Athanasiadis, 1996a:151, fig. 70A–G.

Callithamnion fragilissimum Zanardini, 1860:11, table III, B.

Antithamnion fragilissimum (Zanardini) De Toni, 1903:1408.

Antithamnion ogdeniae I. A. Abbott, 1979:218, figs. 11–14.

Thallus with erect axes, up to 1.3 cm tall, arising from prostrate portions. Axial cells of erect filament develop an opposite 

pair of determinate whorl branches at their distal end; whorl 

branches subdistichously to decussately arranged along bearing 

axis, somewhat congested toward the apices. Cells of main axes 

30–120 μm in diameter and 96–120(–240) μm long. Shorter 

cuboidal cell, 10–35 μm long, at the base of whorl branches. 

Whorl branches of a pair are of nearly equal development (subequal). Whorl branches are branched in alternate pattern, but 

occasionally an opposite pair of short branchlets develops at 

the lowest part of a whorl branch. Most whorl branches 250–

700(–950) μm long and gently attenuate. Indeterminate laterals paired with an opposite determinate whorl branch along the 

axes, new indeterminate laterals commonly also develop from 

the cuboid basal cell of determinate whorl branches. Gland cells 

occasional to frequent, 8–16 μm in diameter; borne on short 2, 

3(–5)-celled second-order branchlets, each gland cell resting on 

2 cells. Gland cell branchlets more common on cells in the lower 

half of whorl branches. Rhizoids issued by cuboid basal cells of 

whorl branches, unicellular or multicellular, of variable lengths, 

occasionally terminating in a digitate attachment disc.
NUMBER 96 • 159

Tetrasporangia sessile, 60–70(–75) μm long, 30–47 μm in 

diameter, oblong-ellipsoidal to obovate, borne adaxial on the 

basal cell (or contiguous cells) of first order branchlets (alternate 

branchlets) of the whorl branches. Gametangial thalli not seen in 

Gulf of California material.

Habitat. Epiphytic on Sargassum and other algae; 

lowermost intertidal to shallow subtidal, down to 10 m depths.

Distribution. Gulf of California: Punta Pelícano 

(vicinity of Puerto Peñasco) to El Desemboque; Caleta de Santa 

María (north of Puerto Santa Rosalía) to Cabeza Ballena. Central Pacific: Hawaiian Islands.

Type Locality. Nice, Provence-Alpes-Côte d’Azur, 

France, western Mediterranean Sea.

Remarks. Specimens from Punta Pelícano (JN-4230, 

JN-4242), Puerto Peñasco (JN-4394), El Desemboque (JN-5168, 

JN-5191), Punta Robinson (JN-4866), Punta Cirio (JN-4921), 

Sonora and Caleta de Santa María (JN-3404) and Cabeza Ballena (JN-4145, JN-4146), Baja California Sur, establish Antithamnion decipiens in the Gulf of California.

Antithamnion defectum Kylin

FIGURE 70

Antithamnion defectum Kylin, 1925:46, fig. 27a,b; Smith, 1944:308, pl. 

78: figs. 1, 2; Inagaki, 1950:24, fig. 3; Dawson, 1961b:438; West and 

Norris, 1966:55, fig. 6; Wollaston, 1972a:75, figs. 1–4; Wollaston, 

1976:573, fig. 517; Devinny, 1978:359; Young, 1979:42, figs. 1–13; 

Young and West, 1979:49, figs. 1–18; Young, 1980:119, figs. 1–5; 

Lindstrom and Gabrielson, 1989:222, fig. 1; Scagel et al., 1989:141; R. 

Aguilar-Rosas et al., 1990:125 ; González-González et al., 1996:173; 

S.-R. Lee et al., 2005:534, fig. 1.

Antithamnion pygmaeum N. L. Gardner, 1927e:413, pls. 91–93; Smith, 

1944:309, pl. 78: fig. 4, pl. 80: fig. 1; Dawson et al., 1960b:24; 

Dawson, 1961b:438; 1962a:21, pl. 6: fig. 2; Dawson and Neushul, 

1966:182; West and Norris, 1966:55, fig. 2; Norris and West, 

1967:144; González-González et al., 1996:174.

Antithamnion setaceum N. L. Gardner, 1927d:373, pls. 73, 74.

Antithamnion secundatum sensu Dawson, 1962a:22, pl. 7: fig. 3; GonzálezGonzález et al., 1996:174 [non Antithamnion secundatum N. L. Gardner, 1927e:413; see Wollaston, 1972a:79].

FIGURE 69. Antithamnion decipiens: A. Erect axis showing alternately branched whorl branches with gland cells borne on short branchlets and 

an indeterminate branch (JN-4921, US Alg. Coll. microscope slide 4750). B. Tetrasporangia sessile borne on first order branchlets (JN-4146, 

US Alg. Coll. microscope slide 4719).
160 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Antithamnion dendroideum sensu Norris, 1975:436; Pacheco-Ruíz and 

Zertuche-González, 2002:468; Pacheco-Ruíz et al., 2008:211 [non Antithamnion dendroideum G. M. Smith et Hollenberg, 1943:217].

Algae to 2(–7) mm high, main axes percurrent, indeterminate laterals alternately and distichously arranged along axes, 

without a paired determinate whorl branch opposite them. Axial 

cells cuboid above, cylindrical below, up to 105 μm in diameter and up to 245 μm long. Each axial cell at their distal end 

bears 2 opposite whorl branches. Whorl branches distichously 

arranged along bearing axes. Cells at the base of whorl branches 

are shorter (23–35 μm) than adjacent cells and can develop rhizoids that often end in digitate attachment discs. Whorl branches 

10–13 cells long, up to 725 μm in length; whorl branches bearing secundly a single order of up to 8 simple adaxial branchlets. 

Adaxial branchlets somewhat outwardly curved. Ultimate cells 

of all branches and branchlets acute. Gland cells usually borne 

on inner branchlets of whorl branches, branchlets usually 3 or 

more cells long, gland cells common near tip or in upper half of 

branchlet, overlying 2(–3) cells.

Tetrasporangia ovoid, up to 80 μm long, cruciately divided, borne on unicellular pedicels (apparently reduced ultimate branchlets) or terminally and laterally off inner ultimate 

branchlets (see Gardner, 1927e: fig. 93). Carpogonial branch as 

for genus. Spermatangia in terminal whorls on short cylindrical 

heads, arising adaxially in place of branchlets on the inner cells 

of whorl branches and second-order branchlets (reproductive information after Abbott and Hollenberg, 1976).

Habitat. On rocks or epiphytic on other algae; subtidal, 12–26 m depths.

Distribution. Gulf of California: Isla Ángel de la 

Guarda; Islas de Los Gemelos (Los Hermanitos), Bahía de Los 

Ángeles; Canal de San Lorenzo (between southern end of Isla 

Espíritu Santo and north of Punta San Lorenzo). Eastern Pacific: 

Alaska to Islas Todos Santos (off Ensenada), Baja California.

Type Locality. Syntype localities (Kylin, 1925): 

Friday Harbor (San Juan Island), Canoe Island (off SE of Shaw 

Island and NW end of Lopez Island), and Peavine Pass (channel 

between Orcas Island and Blakely Island), all San Juan County, 

FIGURE 70. Antithamnion defectum: Upper portion of axes showing new axes (indeterminate branches) issued without an opposite paired 

whorl branch, and gland cells borne distally on inner branchlets. A. JN-4758b, US Alg. Coll. microscope slide 4295. B. JN-4757, US Alg. Coll. 

microscope slide 4731.
NUMBER 96 • 161

Washington, USA. Lectotype locality: Friday Harbor, San Juan 

Island (Smith, 1944), and, later, Canoe Island (Lindstrom and 

Gabrielson, 1989; Athanasiadis, 1996a).

Remarks. Antithamnion defectum is known in the 

northern Gulf (Dawson, 1962a, as A. secundatum). The species 

has been variously interpreted, but herein it is recognized as a 

distinct species.

It has been considered conspecific with A. densum (Shur) M. 

Howe on the basis of morphological studies (Athanasiadis, 1990, 

1996a; Maggs and Hommersand, 1993). More recently, S.-R. Lee 

et al. (2005), using molecular analyses, concluded material identified as “A. densum” should be treated as three separate species. 

The North Atlantic “A. densum” was genetically distinct from 

the North Pacific “A. densum,” which was found to be two different species (S.-R. Lee et al., 2005). One, A. defectum Kylin, 

was restricted in distribution to the northeastern Pacific, and the 

other, A. sparsum Tokida (1932; Yoshida, 1981), was restricted 

to the western Pacific. The third, A. densum (Suhr) M. Howe 

(1914; basionym: Callithamnion densum Suhr, 1840; type locality: Peru), was thought to be restricted to Peru and northern Chile 

(Dawson et al., 1964; Ramírez and Santelices, 1991), but it has 

also been reported in the northeastern Atlantic (L’Hardy-Halos, 

1968b; Guiry and Maggs, 1991; Maggs and Hommersand, 

1993), where it may have been introduced (Athanasiadis, 1990).

Antithamnion kylinii N. L. Gardner

FIGURE 71

Antithamnion kylinii N. L. Gardner, 1927e:411, pl. 89: fig. 1; Smith, 

1944:307, pl. 77: fig. 1, pl. 78: fig.5; Dawson, 1954e:342; Dawson et 

al., 1960b:24; Dawson, 1961b:438; Wollaston, 1972a:78, figs. 10–13; 

1976:574, fig. 520; Scagel et al., 1989:142; Lindstrom and Gabrielson, 1989:222, fig. 2; Stewart, 1991:124; González-González et al., 

1996:174; Athanasiadis, 1996a:160, fig. 76A–C; Pacheco-Ruíz et al., 

2008:211. 

Antithamnion densum sensu Howe, 1914:153, fig. 14 [in part; his description 

only, excluding the type; non Antithamnion densum (Suhr) M. Howe, 

1914:151[type specimen only; see Athanasiadis, 1996a:162]. 

Antithamnion secundatum N. L. Gardner, 1927e:413.

Antithamnion nematocladellum R. E. Norris, 1987b:26, figs. 11, 12, 15 [see 

Athanasiadis, 1996a:160].

Algae in tufts, up to 2 cm high; most cells of indeterminate 

axes producing at their distal end 2 opposite whorl branches. 

Cells of main axes small and cuboid above; cylindrical and 

75–120 μm in diameter and 200–600 μm long basally. Whorl 

branches are not strictly distichously arranged, diverging to decussate, with a small cuboid cell, 8–23 μm diameter at the base 

of each whorl branch. Determinate whorl branches 12–15 cells 

long (to 720 μm long), adaxially ramified, with up to 8 pectinate branchlets; opposite whorl branches often unequal. Whorl 

branches and branchlets tapering to an acute apical cell. Indeterminate branches replacing a whorl branch in a pair, borne 

opposite a determinate whorl branch that is often simple or less 

branched than neighboring whorl branches. Successive indeterminate laterals alternately positioned along bearing axes. Gland 

cells, 12 μm wide by 13–23 μm long, frequently on short 2- to 

4(–6)-celled branchlets. Typically, 1 gland cell per branchlet, 

gland cell in contact with 2 cells.

Tetrasporangia cruciately divided, ovoid, about 70 μm long; 

borne on 1-celled pedicels, along several successive inner cells 

of whorl branches on the adaxial side. Cystocarps not seen in 

northern Gulf specimens. Spermatangia terminal on spermatangial parent cells whorled about cells of short fertile branches, 

forming cylindrical heads borne in a series on the adaxial side of 

inner cells of whorl branches. 

Habitat. On mollusk shells and epizoic on the carapace of the black sea turtle (tortuga negra), Chelonia mydas 

agassizii; subtidal, down to at least 15 m depths. 

Distribution. Gulf of California: Canal de Infiernillo (between Isla Tiburón and Sonora). Eastern Pacific: southern British Columbia to Punta San Hipólito, Baja California; 

Galápagos Islands; Peru. Western Pacific: Korea. 

Type Locality. On log floats; Victoria Harbor, Victoria, Vancouver Island, British Columbia, Canada. 

Remarks. Our collections from Canal de Infiernillo 

(between Isla Tiburón and the Sonoran coast), JN-4733 and JN4735, subtidal, on shells, west of Campo Viboras, and JN-4780, 

JN-4781, JN-4783, and JN-4784 from the carapace of a sea 

turtle, Chelonia mydas agassizii, vicinity of Campo Ona, now 

establish A. kylinii in the northern Gulf of California. 

Ceramiaceae tribus Dohrnielleae

Ceramiaceae tribus Dohrnielleae Feldmann-Mazoyer, 1940 [‘1941’]:241.

The tribe is represented by two genera in the northern Gulf 

of California.

Antithamnionella Lyle

Antithamnionella Lyle, 1922:347, figs. 1–4.

Algae are monosiphonous filaments that may be erect 

or of erect axes arising from prostrate axes and uncorticated 

throughout, with a variable number of branches per whorl, 1–6 

subequal or irregularly unequal whorl branches cut off from 

each axial cell. Whorl branches may be simple but are usually 

branched. In different species whorl branches can be consistent or inconsistent in number and arrangement. The basal cell 

of whorl branches (periaxial cells) may be smaller, similar, or 

larger in size than adjacent whorl branch cells (depending on 

species). Lateral indeterminate axes generally replace a whorl 

branch, and new axes can also develop from basal cells of whorl 

branches. Rhizoids develop from the periaxial cells of prostrate 

axes and from axial cells of erect axes near basal regions. Cells 

are uninucleate. Depending on the species, gland cells are absent 

or few to common and sessile, borne on a single cell, laterally 

on cells of whorl branches and branchlets, sometimes in a short 

series on successive cells. 

Tetrasporangia are ovoid to near spherical, and tetrahedrally, oblique-cruciately, or cruciate-decussately divided and 
162 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 71. Antithamnion kylinii: A. Bushy habit with opposite whorl branches arranged distichous to decussate (JN-4780, US Alg. Coll. 

microscope slide 4741, male gametophyte). B. Portion showing new axes issued with an opposite whorl branch; whorl branches with adaxial 

unbranched branchlets, and gland cells on short branchlets (JN-4780, US Alg. Coll. microscope slide 4736). C. Tetrasporangia on single-celled 

pedicels, borne adaxially on the inner cells of whorl branches (JN-4735, US Alg. Coll. microscope slide 4729). D. Spermatangial structures borne 

adaxially on the inner cells of whorl branches (JN-4780, US Alg. Coll. microscope slide 4735).
NUMBER 96 • 163

sessile or pedicellate on the inner cells of whorl branches or 

branchlets, typically on basal cells (periaxial cells). Gametophytes are mostly dioecious but are monoecious in some species. 

Carpogonial branches are four-celled and borne on the basal 

cells of whorl branches and may suppress the growth of the 

whorl branch and/or bearing axis. Carposporophytes are surrounded by subtending whorl branches from the axial cell below 

the fertile segment. Spermatangial structures consist of a file of 

spermatangial parent cells (SPC) forming a filament with several 

spermatangia whorled about each SPC, these structures borne 

in a series usually adaxially on whorl branch and branchlet cells 

(after Athanasiadis, 1996a).

Three species of Antithamnionella are reported in the northern Gulf. 

KEY TO THE SPECIES OF ANTITHAMNIONELLA IN THE NORTHERN GULF OF CALIFORNIA

1a. Whorl branches commonly unbranched or rarely unilaterally branched; whorl branches, relatively short, up to 120 μm 

long, frequently in pairs, distichous-opposite or decussately arranged along axis . . . . . . . . . . . . . . A. cf. spirographidis

1b. Whorl branches frequently subdichotomously branched, appearing distichous-alternately branched; whorl branches 

typically longer than above, frequently in whorls of 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

2a. Three (or occasionally 2) whorl branches per axial cell; whorl branches up to 240 μm long . . . . . . . . . A. breviramosa

2b. Two (to three) subequal whorl branches per axial cell; whorl branches up to 360 μm long . . . . . . . . . . . A. sublittoralis

Antithamnionella breviramosa (E. Y. Dawson) E. M. Wollaston

FIGURE 72

Antithamnion breviramosus E. Y. Dawson, 1949b:14, figs. 28, 57; 

1954e:342; 1957c:7; 1959a:28; 1960a:50; 1961b:438; 1962a:14, pl. 

5: fig. 3, pl. 15: fig.1; 1966a:26; 1966b:65; Itono, 1969:30, fig. 1A–D.

Antithamnionella breviramosa (E. Y. Dawson) E. M. Wollaston in Womersley and Bailey, 1970:322; Wollaston, 1972a:84, figs. 22–25; Abbott and 

Hollenberg, 1976:580, fig. 523; Schnetter and Bula-Meyer, 1982:147, 

pl. 24: figs. E,F; Mateo-Cid and Mendoza-González, 1992:21; 

Mendoza-González and Mateo-Cid, 1992:20; Serviere-Zaragoza et al., 

1993a:483; Mateo-Cid and Mendoza-González, 1994b:41; MendozaGonzález et al., 1994:108; Bula-Meyer, 1995:36; González-González 

et al., 1996:174; Mendoza-González and Mateo-Cid, 1996b:67, pl. 6: 

figs. 21–25; Athanasiadis, 1996a:105, fig. 46A–E; Abbott, 1999:253, 

figs. 71A–C; Pacheco-Ruíz and Zertuche-González, 2002:468; Dreckmann et al., 2006:155; Fernández-García et al., 2011:60.

Antithamnionella elegans sensu Riosmena-Rodríguez et al., 1998:26; MateoCid et al., 2000:66; L. Aguilar-Rosas et al., 2000:131; 2002:235; 

CONANP, 2002:138; Mateo-Cid et al., 2006:56; Bernecker, 2009:CDRom p. 64 [non Antithamnionella elegans (Berthold) J. H. Price et D. 

M. John in J. H. Price et al., 1986:16; basionym: Antithamnion elegans

Berthold, 1882a:516; see also Cormaci and Furnari, 1989:264].

Algae up to 3 mm high, composed of creeping prostrate 

axes and erect axes; attached by simple uniseriate rhizoids 

that sometimes end in multicellular digitate discs. Axial cells in 

middle portions 30 μm in diameter and 60–150 μm long (2–5 

times the diameter in length). Axial cells at their distal end issuing whorl branches, usually in whorls of 3 (basally sometimes 

only 2 laterals in a whorl). Indeterminate branches arise irregularly and replace one of the whorl branches in the whorl or may 

arise from basal cells (periaxial cells) of whorl branches. Whorl 

branches up to 150(–240) μm long, composed of 7–11(–13) 

cells, gradually attenuated, with branch tips mostly blunt. Whorl 

branches subdichotomously branched, commonly appearing 

distichous-alternately branched, 2–4(–5) times divided starting 

at the second to third cell in branch, sometimes unbranched. 

Cells of whorl branches 10–15 μm in diameter. Gland cells elliptical, 9–14 μm in length, often frequent; borne single, laterally, 

developed at apex on terminal whorl-branch cells. Gland cells 

sometimes in a short series on successive cells.

Tetrasporangia tetrahedrally divided, ovoid to oblongate, 

up to 40 μm long; borne sessile and adaxial on basal or second cell of whorl branches. Gametophytes unknown in the Gulf 

of California, as known elsewhere, monoecious or dioecious 

with carpogonial branches borne on basal cells of short 2-celled 

branches. Cystocarps single, borne near apex of bearing branch, 

inhibiting its growth. New axis sympodially developing from 

a periaxial cell of whorl branches below the carposporophyte. 

Carposporophytes surrounded by subtending whorl branches 

from below the fertile segment. Spermatangia in clusters on short 

(up to 2-celled) filament, adaxial on inner 3–5 cells of whorl 

branches. 

Habitat. Epiphytic on Prionitis or other larger algae; 

subtidal, down to 16 m depths.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Cabo San Lucas; Mazátlan, Sinaloa 

to Jalisco. Eastern Pacific: southern California to Todos Santos, 

Baja California Sur; Colima; Chiapas; El Salvador; Costa Rica; 

Colombia; Galápagos Islands. Central Pacific: Hawaiian Islands. 

Western Pacific: Korea; Wake Island (northern Marshall Islands).

Type Locality. Drift, epiphytic on Sargassum palmeri Grunow; Pebbly Beach, southeast of Avalon, Santa Catalina 

Island, California Channel Islands, southern California, USA.

Remarks. Cormaci and Furnari (1988) consider Antithamnionella breviramosa to be a synonym of A. elegans (Berthold) J. Price et D. M. John (in J. Price et al., 1986; basionym: 

Antithamnion elegans Berthold, 1882a), a conclusion that was 

followed by some phycologists (e.g., Lawson and John, 1987; 

Stewart, 1991; Silva et al., 1996a). However, on the basis of differences in the numbers of whorl branches, their branching pattern, place of gland cell initiation, and gametophyte structure, 

other researchers (e.g., Itono, 1969; G.-H. Kim and Lee, 1990; 

Athanasiadis, 1996a; Abbott, 1999) recognize A. breviramosa 

and A. elegans as distinct species. Antithamnionella breviramosa

with carpogonial branches on reduced 2-celled laterals, and spermatangial parent cells forming 2-celled filament, while A. elegans
164 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 72. Antithamnionella breviramosa: A. Habit, long whorl branches repeatedly divided (JN-4435, US Alg. Coll. microscope slide 4727). 

B. Habit, whorl branches branching a moderate amount (JN-4908, US Alg. Coll. microscope slide 4751). C. Habit, most of the whorl branches 

are unbranched, with some rhizoids (JN-5064b, US Alg. Coll. microscope slide 4840). D. Lower portion of axis showing 3 whorl branches per 

axial cell and rhizoids developing from periaxial cells (JN-5042, US Alg. Coll. microscope slide 4757). E. Distichous, alternately branched whorl 

branch with gland cells borne on a single cell (JN-5042, US Alg. Coll. microscope slide 4757). F. Tetrasporangia borne on proximal cells of 

whorl branches (EYD-26126, US Alg. Coll. microscope slide 788).
NUMBER 96 • 165

has carpogonial branches on normal size whorl branches and 

spermatangial parent cells forming filaments up to 4 cells long 

(Athanasiadis, 1996a). Japanese records of “Antithamnionella 

breviramosa” of Itono (1969, 1977a: fig. 49H) should be reexamined, as Athanasiadis (1996a) has questioned their identification and generic placement. Antithamnionella breviramosa is 

also reported in the western Atlantic (Wynne, 2005, 2011).

Antithamnionella cf. spirographidis (Schiffner) E. M. 

Wollaston

FIGURE 73

Antithamnion spirographidis Schiffner, 1916:137, figs. 19–27.

Antithamnionella spirographidis (Schiffner) E. M. Wollaston, 1968:345, 

fig. 29A–T; Lindstrom and Gabrielson, 1989:227, fig. 4; Athanasiadis, 

1996a:121, fig. 57A–G.

Thallus of northern Gulf specimen: prostrate and erect axes, 

up to about 3 mm long; basal portion with attachments apparently missing; axial cells bearing 1 to 3 whorl branches. Whorl 

branches often in pairs in a spiral-decussate arrangement; occasionally with a single whorl branch or with 3 branches forming a whorl. Indeterminate branches branching similar to their 

bearing branches; irregular in occurrence, with the number of 

axial cells between indeterminate branches variable. Indeterminate branches can develop either (1) in place of one of the whorl 

branches in a pair, (2) as the third branch to form a whorl, or 

(3) on periaxial cells or infrequently from the second cell of 

whorl branches. Axial cells in lower regions of thallus up to 

55 μm in diameter and to 190 μm in length. Whorl branches 

mostly simple, sometimes sparsely secundly branched; gradually attenuated distally, ending in a blunt tip; periaxial (basal) 

cell of whorl branch usually similar in size to adjacent cells of 

whorl branch but occasionally may be smaller or larger in size. 

Rhizoids apparently not abundant, issued from periaxial cells 

of whorl branches. In upper portions of thallus whorl branches 

short, up to 80–120 μm long, somewhat stiff looking, with short 

cells, isodiametric 7–13 μm in size; in midportions of thallus 

whorl branches more or less straight out (near 90 degrees) from 

axial cell; in lower portions of thallus whorl branches appear 

more flexible and longer, up to 280 μm long, with cylindrical 

cells about 12–15 μm in diameter by 25–30 μm long. Gland cells 

frequent, 7–10 um long, lateral on parent cell, usually a middle 

to lower cell (commonly third or fourth cell) of a whorl branch; 

generally only one gland cell per whorl branch. No reproductive 

structures found.

Habitat. Epizoic on carapace of a living black sea 

turtle, Chelonia mydas agassizii (collected by Seri fishermen); 

surface to subtidal.

Distribution. Gulf of California: Canal de Infiernillo, between Campo Ona and Campo Viboras off the mainland 

coast of Sonora and between the east coast of Isla Tiburón.

Type Locality. Sacchetta, Gulf of Trieste, Adriatic 

Sea, Italy.

Remarks. As currently interpreted in the eastern 

and western Pacific, Antithamnionella spirographidis (Schiffner) 

E. M. Wollaston (1968) is quite broadly defined with a high 

degree of morphological variability that has resulted in a number of previously described species being considered conspecific 

(Wollaston, 1972a, 1976; Lindstrom and Gabrielson, 1989; 

Athanasiadis, 1996a; H.-S. Kim and Lee, 2012)––Antithamnionella glandulifera (Kylin) Wollaston (1972a; basionym: Antithamnion glanduliferum Kylin, 1925), Antithamnion gardneri

G. De Toni (1936a; =A. tenuissimum N. L. Gardner, 1927d; non

A. tenuissimum (Hauck) Schiffner, 1916), and Antithamnionella 

miharae (Tokida) Itono (1977; basionym: Antithamnion miharae Tokida, 1942).

This wide range of variability could include our single specimen of Antithamnionella, which was found growing on a sea 

turtle carapace. Although in habit it somewhat resembles Antithamnion glanduliferum Kylin (1925: fig. 28e; Dawson, 1962a: 

pl. 4: fig. 7), our northern Gulf specimen differs in several ways 

from Antithamnionella spirographidis sensu Lindstrom and Gabrielson (1989), and it may be a different or possibly new taxon. 

Examination of Dawson’s (1962a) Pacific Mexico material identified as Antithamnion glanduliferum (EYD-20267, and -20396; 

US Alg. Coll. microscope slides 207 and 206) show the whorl 

branches on his specimens to be distichously arranged, mostly 

2 whorl branches (rarely with 3 whorl branches) per axial cell, 

and whorl branch initials at the axial apex that develop in a 

clearly unilateral alternating series (see Athanasiadis, 1996a: fig. 

57a; Lindstrom and Gabrielson, 1989: fig. 4). In our Gulf specimen, perhaps due to its decussate-spiral branching or the more 

FIGURE 73. Antithamnionella cf. spirographidis: A. Habit, showing whorl branches decussately arranged. B. Close-up of short whorl 

branches composed of short, squarish cells (A, B, JN-4769, US Alg. 

Coll. microscope slide 4734).
166 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

common occurrence of 3-branch whorls, the axial apex is more 

congested and whorl branch initials do not appear to develop 

in a unilateral alternating series. Many of the whorl branches in 

midportions of the thallus extend more or less straight out from 

the axial cell, in contrast those of A. spirographidis that bend 

upward (e.g., see Kim and Lee, 2012: figs. 38a–f, 39a–f ). The 

Gulf specimen is sterile, thus reproductive structures could not 

be compared.

Other specimens from the Gulf of California reported as 

Antithamnionella spirographidis by Pacheco-Ruíz et al. (2008) 

may be this species but need to be re-examined. Dawson (1966b, 

as “Antithamnion glanduliferum”) concluded that his southern 

Gulf material from Isla Salsipuedes was an “intermediate condition” with both blunt and acute tips on whorl branches and 

related it to the Galápagos Antithamnion veleroae W. R. Taylor (1945). More recently Athanasiadis (1996a:128) considered 

A. veleroae to be a synonym of Antithamnionella ternifolia (J. D. 

Hooker et Harvey) Lyle (1922).

For now our northern Gulf of California specimen (JN4769; US Alg. Coll. microscope slide 4734) is tentatively referred 

to Antithamnionella cf. spirographidis until more material from 

the northern Gulf can be collected, studied, and genetically compared with type material of other species.

Antithamnionella sublittoralis (Setchell et N. L. Gardner) 

Athanasiadis

Antithamnion sublittorale Setchell et N. L. Gardner, 1937:86, pl. 6: fig. 15; 

Dawson, 1944a:313; 1961b:439; 1962a:22, pl. 7: fig.2; Stewart and 

Stewart, 1984:145; González-González et al., 1996:174.

Antithamnionella sublittoralis (Setchell et N. L. Gardner) Athanasiadis,

1996a:119, fig. 55A,B.

Algae composed of a sparingly branched creeping axis and 

erect axes, up to 1 cm tall; each axial cell usually bearing 2(–3) 

whorl branches, arranged in spiral pattern around axes (decussate). Axial cells of main axes 55–65 μm in diameter and 165–

260 μm in length (3–4 times as long as wide). Whorl branches 

200–300(–360) μm long; unbranched or mostly distichousalternately branched, usually incurved; up to 12 cells long. Cells 

of whorl branches 15–30 μm long and 10–15 μm in diameter. 

New axes replacing a whorl-branch at irregular intervals. Gland 

cells develop adaxially from intercalary cells near apices. Gland 

cells borne singly or in a series of up to 3, on successive whorl 

branch cells, smaller than bearing cell.

 Tetrasporangia sessile, borne on periaxial and second cell of 

whorl branches. Carpogonial branches borne on 2-celled whorl 

branches near apices. Carposporophytes borne singly, subtended 

by 3 whorl branches, which may be longer (up to 520 μm long 

and up to 15 cells long) than regular whorl branches.

Habitat. Epiphytes on larger algae; subtidal, 4–30 m 

depths (dredged down to 40 m depths).

Distribution. Gulf of California: Bahía Salinas, 

Isla Carmén; Canal de San Lorenzo (off southern end of Isla 

Espíritu Santo) to San José del Cabo. Eastern Pacific: Isla Guadalupe (off Baja California).

Type Locality. Epiphytic, dredged at 37 m depth; 

San José del Cabo, Baja California Sur, Gulf of California, Mexico.

Irtugovia Perestenko

Irtugovia Perestenko, 1996:140 [in Russian], 204 [in Latin].

Algae are erect, monosiphonous branched filaments, attached by rhizoids developed from lowermost cells near the base 

or having erect axes arising from prostrate axes, uncorticated 

with a variable number of branches per whorl, 1–6 subequal or 

irregularly unequal whorl branches borne on each axial cell. In 

different species, whorl branches can be consistent or inconsistent 

in number and arrangement. Whorl branches may be simple or 

branched. The basal cell of whorl branches (periaxial cells) may 

be smaller, similar, or larger in size than adjacent whorl branch 

cells. Lateral indeterminate axes replacing a whorl branch and 

new axes can also develop from basal cells of whorl branches. 

Growth is apical. Gland cells absent to common, sessile, borne 

laterally on cells of whorl branches, sometimes in a short series 

on successive cells, one per cell. Cells uninucleate.

Tetrasporangia are cruciately divided and ovoid to near 

spherical, sessile or pedicellate on inner cells of whorl branches 

or branchlets. Gametophytes are monoecious or dioecious. 

Carpogonial branches 4-celled; borne on basal cells of whorl 

branches, may suppress the growth of whorl branch or bearing axis. Carposporophytes are surrounded by subtending whorl 

branches. Spermatangia are grouped on spermatangial structures 

borne adaxially on whorl branches and branchlets. 

Remarks. Irtugovia is similar to Antithamnionella,

but it is distichously branched and with successively dividing 

tetrasporangia, borne in short branches, appearing clustered. 

Womersley and Wollaston (in Womersley, 1998) commented that 

Antithamnionella was separated on vegetative features (number and branching of whorl branchlets, position of gland cells) 

and tetrahedrally divided tetrasporangia. Athanasiadis (1996a) 

noted that Irtugovia was not monophyletic but lacked distinctive 

characters and was in need of further study. Later, Athanasiadis 

(2002) found that the distinction of Irtugovia from Antithamnionella was cladistically supported, and included both in the 

tribe Dohrnielleae. However, it remains a little-understood genus 

in need of further elucidation.

Athanasiadis (2002) also noted the genus name Irtugovia 

is a later homonym of Haplocladium Nägeli (1862; generitype: 

H. floccosum (O. F. Müller) Nägeli). There is also a bryophyte 

genus, Haplocladium (Müller Hal.) Müller Hal. (1896; basionym: Hypnum sect. Haplocladium Müller Hal., 1879), but it 

also is a later homonym. Thus, the use of the name Irtugovia

would need to be conserved over Haplocladium Nägeli (Athanasiadis, 2002). 

One species of Irtugovia has been reported in the northern 

Gulf of California.

Irtugovia pacifica (Harvey) Perestenko

Callithamnion floccosum var. pacificum Harvey, 1862:176.
NUMBER 96 • 167

Irtugovia pacifica (Harvey) Perestenko, 1996:142, pl. 18: figs. 13, 14, pl. 22: 

fig. 5.

Antithamnion floccosum f. pacificum (Harvey) Setchell et N. L. Gardner, 

1903:341.

Antithamnion pacificum (Harvey) Kylin, 1925:47, figs. 28C,D, 29A–F; Dawson, 1944a:313; Smith, 1944:310; Dawson, 1961b:439; 1962a:19, pl. 

4: figs. 8, 9; González-González et al., 1996:174.

Antithamnionella pacifica (Harvey) E. M. Wollaston, 1972a:87, figs. 31–36; 

Wollaston, 1976:582, fig. 525; Scagel et al., 1989:226; Lindstrom and 

Gabrielson, 1989:226, tbl. 1, fig. 4. 

Algae erect, uniseriate filaments, lower portions often entangled, distichously branched; usually (1–)2 opposite whorl 

branches per axial cell; periaxial cells smaller than adjacent cells 

in whorl branch. Whorl branches unbranched (except for fertile 

branchlets with reproductive structures). Indeterminate lateral 

branches arising in place of whorl branch. Lower axial cells very 

long, 20(–30) times longer than in diameter. Gland cells are usually entirely absent but are also noted to be rare. 

Tetrasporangia cruciately divided, developing by successive 

divisions (often tetrahedral in appearance); borne terminally or 

laterally on short branches on the adaxial side of whorl branches. 

Carpogonial branches single on basal cell of whorl branches near 

apex of axis; carposporangia in more or less elongate groups. 

Spermatangia on short spermatangial branches borne adaxially 

on inner cells of whorl branches (after Wollaston, 1976). 

Habitat. Epiphytic on larger algae, subtidal (dredged 

22–36 m depths; Dawson, 1944a).

Distribution. Gulf of California: Bahía Tepoca; 

Guaymas. Eastern Pacific: Alaska to Baja California. Western 

Pacific: Russia.

Type Locality. Syntypes: Orcas Island, Washington; Esquimalt, British Columbia, Canada (Harvey, 1862). Lectotype locality: Orcas Island, San Juan Islands, San Juan County, 

Salish Sea, Washington, USA (Lindstrom and Gabrielson, 1989). 

Remarks. Dawson (1962a) noted that his earlier 

collected northern Gulf of California specimens identified as 

“Antithamnion pacificum” (Dawson, 1944a) were missing and 

presumed to be misfiled (AHFH to LAM, now UC). Until his 

specimens are found, more collections are needed to verify the 

presence of Irtugovia pacifica in the Gulf of California. 

Ceramiaceae tribus Delesseriopseae

Ceramiaceae tribus Delesseriopseae Itono et Tak. Tanaka, 1973:251.

There is one genus of the tribe Delesseriopseae found in the 

northern Gulf of California.

Balliella Itono et Tak. Tanaka

Balliella Itono et Tak. Tanaka, 1973:249.

Algae are uniseriate branched filaments and either erect or 

with both erect and prostrate portions. Axial cells bear determinate branches in one plane (distichous) or slightly rotated, which 

are opposite pairs of branches of unequal lengths. Indeterminate 

lateral branches are produced regularly or irregularly depending on species, replacing one of the determinate branches of a 

pair. In mature portions of the axes, ascending and descending 

branched, rhizoid-like filaments arise from the basal cells of the 

determinate branches (i.e., periaxial cells) and encircle the axial 

row of main axes and indeterminate laterals, eventually forming 

a loose or dense pseudoparenchymatous cortex. Spherical vesicular cells (gland cells) are generally on the basal cells of branches 

(periaxial cells) or occasionally on contiguous cells borne adaxially, abaxially, or both, and may also occur on the rhizoid-like 

filaments corticating the axes. Vesicular cells are attached to the 

parent cell by a thin cytoplasmic thread.

Tetrasporangia are spherical to ovoid and cruciately divided 

and can be sessile or pedicellate, single or in clusters, and borne 

adaxially as well as abaxially on the periaxial (and occasionally second) cells or can be on short branchlets arising from the 

periaxial cells. Carpogonial branches are four-celled, with the 

procarps formed at successive levels along main axes, and borne 

singly on periaxial cells; sometimes an axial cell supports fertile 

periaxial cells to both sides. Carposporophytes are surrounded 

by accessory involucral filaments or naked. Spermatangial 

branchlets of 1–4 fertile cells, each with whorl of spermatangial 

parent cells that cut off both spermatangia and new spermatangial parent cells. Spermatangial structures develop along lateral 

branch cells, starting on proximal cells and extending distally, 

borne abaxially and/or adaxially.

Remarks. Additional distinguishing features have 

been tentatively recognized for the genus, pending their discovery in the generitype Balliella crouanioides (Itono) Itono et Tak. 

Tanaka (1973; basionym: Antithamnion crouanioides Itono, 

1971a). These characters include the absence of adventitious development of new axes from periaxial and contiguous cells of 

determinate branches, and the origin of vesicular cells from axial 

cells near the apices and transference to periaxial cells (Huisman 

and Kraft, 1984; Athanasiadis, 1996a). There is one species of 

Balliella known in the Gulf of California.

Balliella pseudocorticata (E. Y. Dawson) D. N. Young

Antithamnion pseudocorticatum E. Y. Dawson, 1962a:20, pl. 7: figs. 1–5; 

González-González et al., 1996:174.

Balliella pseudocorticata (E. Y. Dawson) D. N. Young, 1981:94, figs. 1, 2; 

Athanasiadis, 1996a:43; CONANP, 2002:138.

Bakothamnion curassavicum C. Hoek, 1978:48, figs. 1, 2.

Algae minute, up to 5 mm high; with both prostrate and 

erect axes, upper axes sinusoidal, attached to substratum by 

long, multicellular rhizoids. Axial cells 100–120 μm in diameter 

by 270–300 μm in length; bearing at their distal end an opposite 

pair of distichous, unequal branches. Determinate branches with 

slightly smaller cell than contiguous cells at their base; oppositely 

pinnately branched up to 2 orders. In mature portions, branched 

rhizoid-like filaments issued by periaxial cells loosely corticate 

the axial row of main axes and indeterminate lateral branches. 

Secondary indeterminate lateral branches replacing a branch in 

pair, borne alternately at irregular intervals, up to 5(–10) axial 
168 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

cells apart. Vesicular (gland) cells round, up to 13 μm in diameter, borne abaxially and singly (up to 2 in older portions of thallus) on basal cells of lateral branches (periaxial cells). Corticating 

rhizoid-like filaments may also bear vesicular cells.

Reproductive structures have not been observed in Gulf of 

California material. Tetrasporangia, described from specimens 

from Seychelles, are borne adaxially and sessile from basal cells 

of lateral branches (Huisman and Kraft, 1984).

Habitat. On rocks, coral rubble, and worm tubes; 

shallow subtidal (also dredged to about 20 m depths).

Distribution. Gulf of California: Bahía de Loreto 

to La Paz. Eastern Pacific: Isla Fernandina, Galápagos Islands.

Type Locality. Dredged 4–10 fathoms (7.3–18.3 

m); Canal de San Lorenzo (channel between the southern end of 

Isla Espíritu Santo and northern peninsula from Punta Coyote 

to Punta San Lorenzo), near entrance to Báhia de La Paz, Baja 

California Sur, Gulf of California, Mexico.

Remarks. Balliella pseudocorticata is apparently uncommon in the Gulf of California. It has a wide distribution: 

reported in the western Atlantic from Bermuda (Schneider and 

Searles, 1997), Florida (Dawes and Mathieson, 2008), Puerto 

Rico (Ballantine and Wynne, 1986), the Greater Antilles (Littler and Littler, 2000), Curaçao (Hoek, 1978, as “Bakothamnion 

curassavicum”), and Colombia (Díaz-Pulido and Díaz-Ruíz, 

2003); in the Indian Ocean from the Seychelles (Huisman and 

Kraft, 1984) and Maldive Islands (Silva et al., 1996a); and in 

the Pacific from the Galápagos Islands (Young, 1981) and New 

Zealand (Adams, 1994).

Ceramiaceae tribus Ceramieae

Ceramiaceae tribus Ceramieae Fries, 1836:302; Athanasiadis, 1996a:180.

There are four genera of the tribe Ceramieae present in the 

northern Gulf of California. Athanasiadis (1996a) noted that the 

entire group is in need of a systematic revision. 

Centroceras Kützing

SEE FIGURE 89A

Kützing, 1842 [1841]:731; Kylin, 1956:379.

Algae erect, often from prostrate axes, composed of cylindrical uniseriate axial filaments entirely corticated by a single 

layer of smaller cells; basipetal cortical cells rectangular, arranged in closely spaced longitudinal rows parallel to the axes. 

Apices often forcipate; branching is subdichotomous, trichotomous, tetrachotomous, alternate, subsecund, or irregular, with 

all orders of branching similarly corticated. The cells of the 

axial filament each cut off a ring of 6–20 periaxial cells at their 

upper end. The first periaxial cell issues 4 cortical initials, while 

each of the other periaxial cells cut off 3 cortical initials that 

develop the cortical filaments—2 short acropetal filaments and 

1 basipetal filament. One of the acropetal initials also cuts off 

a basipetal (descending) filament secondarily, and this filament 

and the basipetal-initial-produced filament (i.e., 2 descending 

filaments per periaxial cell) extend to match the elongation of 

the axial cell. Axes completely corticated, with a segmented appearance as successive axial cells are individually corticated. 

The majority of cortical growth is in the basipetal direction, 

and cells of the long basipetal filaments are rectangular. Most 

species have one to many spines formed at the nodes by the 

acropetally produced cortical cells, and gland cells are present 

in many species (although they may be inconspicuous). Rhizoids are uniseriate and multicellular, issued at nodes by periaxial cells, rarely by cortical cells.

Tetrasporangia develop from the periaxial cells and are usually tetrahedrally divided; initial issued abaxial and subsequently 

become whorled at nodes. Tetrasporangia protrude from the 

cortex and may be naked or subtended by involucral filaments 

or spines or both. Gametophytes are dioecious. Carpogonial 

branches 4-celled, issued by periaxial cells in a row along upper 

portions of fertile thalli. Mature cystocarps are sessile, spherical, 

and encircled by several short involucral branches. Spermatangia form dense sori, whorled about the nodes. Spermatangia are 

minute elliptical to clavate cells borne terminally, singly or in 

groups of twos and threes on specialized monosiphonous freely 

branched filaments that arise from the anterior portion of periaxial cells.

Remarks. Although not observed in Gulf of California specimens of Centroceras, specialized asexual reproductive 

structures termed “missiles” have been reported in C. clavulatum from the Red Sea (Lipkin, 1977). They are proposed to be 

the alga’s response to intense grazing pressure.

Two species of Centroceras are known in the northern Gulf 

of California.

KEY TO THE SPECIES OF CENTROCERAS IN THE NORTHERN GULF OF CALIFORNIA

1a. Gland cells at nodes flattened; tetrasporangia projecting from cortex, involucres absent . . . . . . . . . . . . . . C. clavulatum

1b. Gland cells at nodes ovoid; tetrasporangia with 4- to 6-celled involucres . . . . . . . . . . . . . . . . . . . . . . . . . C. gasparrinii

Centroceras clavulatum (C. Agardh) Montagne

Ceramium clavulatum C. Agardh in Kunth, 1822:2.

Centroceras clavulatum (C. Agardh) Montagne, 1846b:140; J. Agardh, 

1851:148; Harvey, 1853:211, pl. 33: fig. C; Howe, 1911:509; Setchell 

and Gardner, 1924:779; Okamura, 1936:743, fig. 355; Kylin, 1941:30; 

Smith, 1944:328, pl. 84: figs. 5, 6; Dawson, 1944a:321; 1962b:68, 

pl. 26: fig. 7, pl. 27: fig. 3; Huerta-Múzquiz and Tirado-Lizárraga, 

1970:129; Chávez-Barrear, 1972b:269; Huerta-Múzquiz and GarzaBarrientos, 1975:9; Abbott and Hollenberg, 1976:604, fig. 547; Itono, 

1977a:35, 118, 201, figs. 16A,B, 39A,B; Huerta-Múzquiz, 1978:335; 

Pedroche and González-González, 1981:66; Stewart and Stewart, 

1984:145; Boo and Lee, 1985:298, figs. 1–6; Mendoza-González and 
NUMBER 96 • 169

Mateo-Cid, 1986:425; Sánchez-Rodríguez et al., 1989:44; Dreckmann 

et al., 1990:32; Stewart, 1991:127; Mateo-Cid et al., 1993:48; LeónTejera et al., 1993:200; González-González et al., 1996:184; AnayaReyna and Riosmena-Rodríguez, 1996:864. tbl. 1; Yoshida, 1998:886, 

fig. 3-84C–E; Abbott, 1999:261, fig. 73A–F; Mateo-Cid et al., 2000:66; 

L. Aguilar-Rosas et al., 2000:131; Cruz-Ayala et al., 2001:191; MateoCid et al., 2006:56; Serviere-Zaragoza et al., 2007:9.

Algae tufts, 0.5–3.0 cm tall; with axes 150–320 μm in diameter; subdichotomously branched or occasionally trichotomous; 

branching at intervals of 9–10 axial cells in the main axes and 

intervals of 6–9 axial cells in lateral axes. Apices forcipate and 

slightly inrolled. Short proliferous branches with undivided inrolled apices common in lower portions of thallus. Periaxial cells 

12–16 at a node; first periaxial cell produces 4 cortical initials; 

all other periaxial cells each cut off 3 cortical initials, 2 acropetally and 1 basipetally. First cortical initial may cut off 1 or 2 

cells acropetally; one a cortical cell and the other may be a spine; 

or 1 flattened gland cell; or 2 cortical cells. Second cortical initial 

cuts off 1 cell acropetally and a filament basipetally. The third 

cortical initial produces a descending (basipetal) file of cells. The 

2 basipetally directed filaments keep pace with the elongation of 

the axial cell, completely corticating the thallus. Cortical cells 

subrectangular, 10–18 μm high, 5.0–10.5 μm wide; arranged in 

unbranched longitudinal rows. Acropetal cortical filaments 2 

cells long (including cortical initial); basipetal filaments 18–25 

cells long. Straight, 3-celled spines few to many, up to 50 μm 

long; whorled about the nodes, adding to the segmented appearance of the thallus. Segments reach 360–600 μm in length at the 

basal dichotomies; decreasing in length toward apices. Rhizoids 

1 to several cells long, issued from periaxial cells at the nodes, 

often ending in a multicellular attachment pad.

Tetrasporangia tetrahedrally divided, 35–45(–50) μm in diameter; emergent and whorled about the nodes (see Joly, 1965: 

fig. 502; Itono, 1977a: fig. 39A, B); usually borne in distal segments of erect axes or in short proliferous branches. Gametophytes dioecious. Cystocarpic thalli were not found in Gulf 

collections. Spermatangial clusters of 2–3 clavate spermatangia, 

terminal on specialized, freely branched, uniseriate filaments 

arising from the upper end of periaxial cells; densely whorled at 

the nodes.

Habitat. On rocks, tidal platforms, or other algae; 

low intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Eureka; Mazatlan, Sinaloa to Narayit. Eastern Pacific: Santa 

Cruz, California, to Peru; Isla Socorro and Isla San Benedicto 

(Islas Revillagigedo); Guererro to Oaxaca. Central Pacific: Hawaiian Islands. Western Pacific: Japan; Korea.

Type Locality. Callao (west of Lima), Provincia 

Constitucional, Peru.

Remarks. Cystocarps, although not found in Gulf 

material, have been described for C. clavulatum elsewhere: cystocarps of western Atlantic specimens were bilobed and partly 

surrounded by several involucral filaments and borne laterally 

(Taylor, 1960). Molecular and morphological studies on the 

broadly defined “Centroceras clavulatum complex” found it to 

include a number of distinct species (Won et al., 2009). On the 

basis of phylogenetic analyses and consistent morphological differences, three previously described species were resurrected, including C. gasparrinii, along with two others that were described 

as new species (Won et al., 2009). In light of this study, all Gulf 

of California and Pacific Mexico specimens referred to “Centroceras” should be re-examined to determine if they are correctly 

identified or represent other species.

Centroceras gasparrinii (Meneghini) Kützing

FIGURE 74

Ceramium gasparrinii Meneghini, 1844a:186.

Centroceras gasparrinii (Meneghini) Kützing, 1849:689; Won et al., 

2009:231, figs. 3a–o, 4a–h,11a–d, 14b,h.

Centroceras inerme Kützing, 1849:688; Kützing, 1863:7, pl. 17, figs. e–g; 

Titlyanova et al., 2006:202.

Centroceras clavulatum var. inerme (Kützing) Piccone, 1886:54; Dawson, 

1966a:27; 1966b:65; González-González et al., 1996:184.

Ceramium clavulatum var. inerme (Kützing) Weber-van Bosse, 1923:322.

Thalli of erect and prostrate axes, up to 6 cm high and to 

265 μm in diameter, subdichotomously or occasionally trichotomously branched (rarely a tiny fourth branch occurs), with the 

third branch in the middle of a fork and smaller. Erect axes with 

forcipate tips, inrolled to some degree; branching at intervals of 

10–12 axial cells in both the main and lateral axes, and adventitious branches may develop from periaxial cells at the nodes in 

lower portions of thallus. Nodes with 12–19 periaxial cells; all 

periaxial cells initiate smaller-celled filaments that form the cortex. Mature cortex of rectangular cells (about 10 μm in diameter 

by 14–25 μm in length) in regular longitudinal rows, completely 

covering the axial cells. Except for the first periaxial cell produced at a node, most periaxial cells issue 2 acropetal initials at 

their anterior end and 1 basipetal initial at their posterior end. 

Acropetal ascending filaments 1–2 cells long (except when with 

spines and longer tetrasporangial involucres), and the basipetally 

directed filaments (one from the acropetal initial and one from 

the basipetal initial), 13–23 cells long. Straight, 3-celled spines 

(including the cortical initial) in a whorl at each node throughout 

the thallus. Gland cells ovoid, at distal end of node, about 10 μm 

in diameter. Multicellular uniseriate rhizoids, 25–40 μm in diameter, issued at the nodes by periaxial cells, often end in digitate 

pads and attach the alga to its host or the substratum.

Tetrasporangia tetrahedrally divided, 30–45 μm in diameter and about 50 μm long (excluding the sheath), emergent, 

subtended by unbranched involucral filaments, 4–6 cells long, 

arising from first cortical initials or transformed from spines. 

Tetrasporangia whorled about nodes usually borne in distal segments of erect axes or in short proliferous branches.

Habitat. On rocks and in algal turf; intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía San Carlos; El Tecolote, Bahía de La Paz to Cabeza 

Ballena. Eastern Pacific: California; Baja California; Panama. 

Central Pacific: Hawaiian Islands. Western Pacific: Japan; Korea.
170 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 74. Centroceras gasparrinii: A. Apical region showing dichotomously to trichotomously branched axis, forcipate and inrolled 

apices, with numerous spines (JN-4285, US Alg. Coll. microscope slide 4792). B. Spermatangial branchlets whorled at nodes (JN-4131a, 

US Alg. Coll. microscope slide 4784). C. Detail of cortex showing cells arranged in longitudinal rows and spines whorled at nodes (JN4131b, US Alg. Coll. microscope slide 8700). D. Tetrasporangia whorled at nodes, subtended by 5- to 6-celled involucres (JN-4131e, US 

Alg. Coll. microscope slide 4759).
NUMBER 96 • 171

Type Locality. Palermo, northwest coast of the island of Sicily, Mediterranean Sea, southern Italy.

Remarks. On the basis of molecular and morphological differences, Won et al. (2009) distinguished Centroceras 

gasparrinii from others of the “Centroceras clavulatum complex.” The characteristic emergent tetrasporangia, involucres, 

and spines now recognized for C. gasparrinii were illustrated by 

Norris and Bucher (1982: fig. 102, as “C. clavulatum”).

Ceramium Roth

Ceramium Roth, 1797:146.

Algae are monosiphonous, generally terete filaments, with 

both prostrate and erect or decumbent axes that are subdichotomously, alternately, or irregularly branched. Axes are composed of a central axial row of larger cells that each produce at 

their distal end a ring of 4 or more smaller periaxial cells that 

each usually give rise to (1–)3–5 cortical initials that develop 

smaller-celled filaments of limited growth, acropetal filaments 

(ascending toward apices), and/or basipetal filaments (descending toward base) that form the relatively consistent cortical 

pattern. In some species pseudoperiaxial cells divide off laterally from periaxial cells, increasing the number of cells in the 

periaxial ring; these pseudoperiaxial cells may also issue cortical filaments. Axes are completely or incompletely corticated 

(leaving a noncorticated internodal space) by ovoid to angular 

cells. In some species the cortex is completed early, whereas 

in others development continues to elaborate the cortical pattern, making nodal bands more variable from young to older 

portions. Diagnostic characters for species separation are the 

number of periaxial cells in the ring at a node, the presence or 

absence of pseudoperiaxial cells, the number and positions of 

cortical filament initials, the development and mature pattern 

of cortical filaments that form the cortex, tetrasporangial features, and the thallus branching pattern. Multicelluar rhizoids 

develop from both periaxial and inner and outer cortical cells 

and can be blunt tipped or terminate in a multicellular digitate 

or discoid pad. Gland cells are present on cortical filaments of 

some species.

Tetrasporangia are sessile and borne in a variety of positions: solitary, opposite, or whorled at the nodes; and naked or 

surrounded by an involucre formed by upward growth of the 

cortical filaments or embedded completely in the cortex. Tetrasporangia are usually derived from the periaxial cells, but in 

some, especially robust fully corticated species, later tetrasporangia may arise from any inner cortical cell, and so tetrasporangia may appear scattered (Itono, 1977a; Womersley, 1978). 

Gametophytes are dioecious. Carpogonial branch is 4-celled, developed from a periaxial cell, abaxial on the lower lateral side of 

the supporting cell (a periaxial cell). Cystocarps may be terminal 

or intercalary on a branch or in the axils of branch dichotomies. Cystocarps have spherical gonimolobes that may be naked 

or more commonly are surrounded by 1 to several involucral 

branches that arise from the node below. Spermatangial parent 

cells develop from cortical cells and produce spermatangia terminally, forming an external layer of minute, colorless cells that 

cover the surface cortical cells in upper portions of thalli.

Remarks. The genus Ceramium is well represented 

with 26 species reported in the Gulf of California. Species of 

Ceramium are frequently epiphytic on larger algae or sea grasses 

and some are also found on solid substrata.

Four species are recorded only in the southern Gulf: Ceramium codii (H. Richards) Feldmann-Mazoyer (1938; basionym: 

Ceramithamnion codii H. Richards, 1901) from Bahía de La Paz 

(Huerta-Múzquiz and Mendoza-González, 1985, as C. mucronatum Segi, 1944), C. personatum Setchell et N. L. Gardner (1930) 

from Laguna Agiabampo (Ortega et al., 1987), C. monacanthum

J. Agardh (1894) from Punta Arena (Mateo-Cid et al., 2000) 

and Mazátlan (Mendoza-González et al., 1994), and C. giacconei Cormaci et G. Furnari (1991) from a rhodolith bed at Punta 

Perico, northern end of Bahía de los Muertos (Cho et al., 2003b).

Currently, there are 22 species and two varieties of Ceramium known in the northern Gulf, two of which are Gulf endemics, C. obesum and C. periconicum. 

KEY TO THE SPECIES OF CERAMIUM IN THE NORTHERN GULF OF CALIFORNIA

1a. Central axial cells incompletely corticated, corticated at the nodes only (although internodal space may be greatly reduced near apices) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

1b. Central axial cells completely corticated by smaller cells in some region of the axes; complete cortication may be interrupted at internode above a fork (branching point) and/or in basal regions of axes . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Central axial cells completely corticated in some portions of axes but with internodal gaps present at least in basal 

parts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

2b. Central axial cells completely corticated throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3a. Interrupted cortication just above branching point (dichotomy); 4 cortical initials cut off per periaxial cell. . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. interruptum

3b. Cortication not interrupted at first axial cell above a branching point, complete in upper portions of axes; 5 cortical 

initials cut off per periaxial cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Axes completely corticated only in upper portions, some lower portions with cortical nodes slightly separated . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. sinicola var. sinicola
172 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

4b. Axes completely corticated nearly throughout, only extreme lowermost portion with slim internodes between cortical 

nodes ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. sinicola var. johnstonii

5a. Thalli mainly creeping, sturdy (500–1100 μm in diameter), with thick cortex (200 μm or more) . . . . . . . . . C. obesum

5b. Thalli mainly erect, more slender (usually less than 500 μm in diameter), with a thinner cortex than above . . . . . . . . 6

6a. Thalli relatively tall, usually over 2 cm, up to 18 cm; spines sometimes present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6b. Thalli shorter, usually less than 2 cm high; spines absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

7a. Unicellular (to 2-celled) spines common on apices of main axes and on short lateral branchlets; lateral branchlets of 

similar lengths, whorled around a segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. horridulum

7b. Spines lacking or with infrequent multicellular spines; adventitious lateral branchlets longer and of more variable lengths 

than branchlets in C. horridulum, and radially arranged over several segments . . . . . . . . . . . . . . . . . . . . . C. pacificum

8a. Thalli sparsely, irregularly branched; with short branch apices tending to be incurved or “hooked” . . . . . . . C. howellii

8b. Thalli subdichotomously branched; epiphytic on Codium, attached to host by pigmented rhizoids with bulbous tips . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. codicola

9a. Thalli with spines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

9b. Thalli without spines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

10a. Thalli with straight or recurved spines arranged abaxially along upper portions, spines mostly lacking in lower portions 

(deciduous) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. paniculatum (in part)

10b. Spines recurved, whorled at each cortical band throughout much of thallus; spines persistent . . . . . . . C. hamatispinum

11a. Mature cortical band narrow, of 2–3(–4) tiers of cells; no basipetal cortical initials cut off from periaxial cells, acropetal 

cortical filament development only, or initial may look lateral to side of periaxial cell but not proximal (beneath) periaxial 

cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

11b. Mature cortical band of 3 or more tiers of cells; basipetal development slight to extensive . . . . . . . . . . . . . . . . . . . . . 15

12a. In cortical band, most periaxial cells cut off 3 cortical initials, 2 acropetal initials and 1 lateral appearing initial . . . . 13

12b. In cortical band, most periaxial cells cut off 2 acropetal cortical initials; one of which is laterally directed, and this cell 

often cuts off an acropetal cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

13a. Lateral initial produced by a longitudinal (vertical) division of a periaxial cell; the lateral initial does not divide further; 

tetrasporangia naked, protruding . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. periconicum

13b. Lateral initial may divide further; tetrasporangia with involucres . . . . . . . . . . . . . . . . . . . . . . C. mazatlanense (in part)

14a. Axes and branches less than 35 μm in diameter throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. affine var. affine

14b. Axes and branches larger, greater than 40 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . C. affine var. peninsularis

15a. Tetrasporangia naked (without involucre), emergent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

15b. Tetrasporangia involucred or immersed in cortex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

16a. Gland cells usually present, sometimes giving a green iridescence; apices markedly inrolled (circinate) . . . . C. aduncum

16b. Gland cells absent; apices not markedly inrolled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

17a. Lower internodes 1.0–2.5 times taller than broad; cortical cell size within node decreasing in distal direction in upper 

portions of axes; branches less dense and longer in upper portions of thallus . . . . . . . . . . . . . . . . . . . . . . C. caudatum

17b. Lower internodes broader than tall; cortical cell size within a node not changing progressively with direction; branches 

dense and relatively shorter in upper portions of thallus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. zacae

18a. Primary axes mostly prostrate, with some erect filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

18b. Primary axes mostly erect, with some prostrate portions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

19a. Erect axes unbranched or irregularly branched (opposite or alternate branching in prostrate portions); tetrasporangia 

completely immersed in the cortex of short clavate branches, several tetrasporangia per nodal band . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. procumbens

19b. Erect axes sparsely branched (basal portions unbranched to sparsely branched); tetrasporangia protruding through the 

cortex, partially surrounded by corticating filaments at their base, usually solitary (or 2) at a node . . . . . . . . C. serpens

20a. Axes slender, 100 μm in diameter or less . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

20b. Axes more robust, greater than 100 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

21a. Internodes of tetrasporangial axes not reduced; tetrasporangia 25–35 μm in diameter . . . . . . . . . . . . . . . . . C. camouii

21b. Internodes of tetrasporangial axes abruptly reduced in swollen terminal portions; tetrasporangia 30–40 μm in diameter 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. equisetoides

22a. Posterior end of periaxial cells cuts off basipetal corticating cells in descending direction . . . . . . . . . . . . . . . . . . . . . . 23

22b. Periaxial cells cut off pseudoperiaxial cells obliquely in a lateral direction (pseudoperiaxial cells are positioned inbetween 

periaxial cells in nodal ring) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

23a. Axes branching subdichotomous; apices forcipate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. paniculatum (in part)

23b. Axes branching irregular and sparse; apices nonforcipate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. vagans
NUMBER 96 • 173

24a. Cortical bands with 7–8 periaxial cells, each cuts off laterally a pseudoperiaxial cell; both periaxial and pseudoperiaxial 

cells cut off acropetal as well as basipetal initials, and nodal band development occurs in both directions . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. clarionense

24b. Cortical bands with 5(–6) periaxial cells; each periaxial cell cuts off a wedge-shaped pseudoperiaxial cell laterally, nodal 

band development mainly acropetal; only pseudoperiaxial cells may cut off a basipetal initial (appears more or less lateral) 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. mazatlanense (in part)

Ceramium aduncum Y. Nakamura

FIGURE 75; SEE ALSO FIGURE 78A

Ceramium aduncum Y. Nakamura, 1950:158, figs. 2b, 3; 1954:18, figs. 13-2, 

17-4; 1965:138, pl. 2: figs. 1, 2; Noda, 1972:13, fig. 15; Itono, 1972:81, 

fig. 11A; 1977a:34, 113, 199, 267, figs. 13L(1–7), 38D,E, 60E; Meneses, 1995:166, figs. 1–4; González-González et al., 1996:184; Lewis 

and Chiu, 1996: figs. 1–2; Yoshida, 1998:889, fig. 3-84F–H; Abbott, 

1999:266, fig. 74A–D; CONANP, 2002:138; Abbott et al., 2002:303, 

figs. 6–7; Mateo-Cid et al., 2006:56; Pacheco-Ruíz et al., 2008:211; 

H.-S. Kim, 2012:31, figs. 17–19.

Ceramium clarionense sensu Dawson, 1950c:134 [in part], pl. 4: fig. 29; 

1954b:448, fig. 55K; 1961b:440; 1962a:53 [in part; Gulf of California specimens], pl. 18: figs. 5, 6; 1966a:26; Phạm-Hoàng, 1969:236, 

fig. 2.167; Schnetter and Bula-Meyer, 1982:151, pl. 25: figs. C,D, 

pl. 27: fig. A [non Ceramium clarionense Setchell et N. L. Gardner, 

1930:170].

Ceramium sp. nov.? sensu Setchell and Gardner, 1930:173, pl. 7: fig. 25; Nakamura, 1950:159 [see Meneses, 1995:166].

Algae up to 1.0 cm tall; axes mostly erect with creeping 

portions, branching subdichotomously at intervals of 7–8(–12) 

nodes; individual axes up to 350 μm in diameter basally, tapering upward; cortication restricted to nodes; apices forcipate and 

noticeably inrolled; lower portions creeping on the substratum, 

attached by few to many unbranched, uniseriate rhizoids, usually 2–3 cells long, up to 15 μm wide, developed from both 

cortical and periaxial cells. Axial cells mostly isodiametric or 

slightly longer than wide. Internodal space about 100 μm long 

basally, decreasing upward, at times reduced to just a thin line 

FIGURE 75. Ceramium aduncum: A. Upper portion with circinate apices and conspicuous gland cells (JN-5060, US Alg. Coll. microscope 

slide 8701). B. Several emergent tetrasporangia (with a thick hyaline envelope), borne off one side of node (JN-3098, US Alg. Coll. microscope slide 8690).
174 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

near apices. Cortical bands truncate; up to almost twice as broad 

as high. Periaxial cells 6–8(–11) in number, depending on axes 

diameter, each periaxial cell cuts off 2 acropetal cortical initials 

and 2 basipetal initials. Each initial issues corticating filaments 

several cells in length. Nodal cortication up to 3 cell layers thick; 

cortical cell size progressively smaller with successive divisions. 

Surface cortical layer of small angular cells, 7–15 μm in diameter; surface cells absent in gaps near the center of nodal band, 

revealing the larger round periaxial cells beneath. Gland cells 

(10–)24–45 μm in diameter, conspicuous (staining deeply with 

aniline blue); often numerous in both acropetal and basipetal 

corticating filaments (may be responsible for iridescence seen in 

live material); may be sparse or lacking in some specimens.

Tetrasporangia naked, protruding, tetrahedrally divided; surrounded by thick hyaline envelope; 30–40 μm in diameter (not 

including envelope), initially borne adaxially, several per node; 

arising from cortical filament cells, rarely from periaxial cells; later 

scattered throughout the nodal band. Mature cystocarps, 150–

180 μm in diameter, surrounded by several involucral branches. 

Spermatangia minute sessile cells, developing first on the adaxial 

side of a node, then continuing to develop over the cortical band.

Habitat. In tide pools, epiphytic on various algae, including corallines, Sargassum, Padina, and Codium, and epizoic 

on bryozoans and sponges; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena; Nayarit; Isla María Magdalena (Islas Marías; 

Islas Tres Marías). Eastern Pacific: California Channel Islands to 

Laguna Ojo de Liebre (Scammon’s Lagoon), Baja California Sur; 

Isla Guadalupe; Rocas Alijos; Oaxaca; Isla Gorgona, Colombia. 

Central Pacific: Hawaiian Islands. Western Pacific: Japan; Taiwan; Vietnam; Korea.

Type Locality. Gôza, Shima Peninsula, Mie Prefecture (“Sima Province,” Nakamura, 1965), Honshū Island, Japan.

Remarks. There has been some confusion on the 

identity of Ceramium aduncum and C. clarionense in the Gulf.

Reexamination of Dawson’s (1962a) Gulf of California specimens identified as “Ceramium clarionense” (US Alg. Coll.) revealed them to be C. aduncum. Dawson’s (1950c:134) expanded 

description of “C. clarionense” was apparently based on C. aduncum. Examination of isotype microscope slide labeled “type” of 

C. clarionense (AHFH-124, microscope slide 183; now UC) revealed it to have two species: a sterile C. clarionense and a tetrasporic C. aduncum. The features distinguishing C. aduncum are 

its isodiametric or slightly longer than broad axial cells, lack of 

pseudoperiaxial cells in the periaxial ring, refractive gland cells 

usually being present, circinate apices (inrolled tips), and naked 

tetrasporangia, whereas C. clarionense has spherical axial cells, 

pseudoperiaxial cells in the periaxial cell ring, lacks refractive 

gland cells, has strongly incurved apices, and has tetrasporangia 

that are surrounded by involucres (see also Meneses, 1995).

Ceramium affine Setchell et N. L. Gardner var. affine

Ceramium affine Setchell et N. L. Gardner, 1930:172; Dawson, 1944a:317, 

pl. 51: fig. 4; Taylor, 1945:272 [with a query]; Dawson, 1950c:132; 

1961b:439; 1962a:50, pl. 17: fig. 6; 1966a:26; Itono, 1972:78, fig. 5; 

Abbott and Hollenberg, 1976:592, fig. 531; Itono, 1977a:31, 99, 195, 

230, 261, figs. 13B, 15B, 50D, 58D; Stewart and Stewart, 1984:145; 

Huerta-Múzquiz and Mendoza-González, 1985:52; Sánchez-Rodríguez 

et al., 1989:44; Mateo-Cid and Mendoza-González, 1992:21; ServiereZaragoza et al., 1993a:483; González-González et al., 1996:184; 

Anaya-Reyna and Riosmena-Rodríguez, 1996:864, tbl. 1; Yoshida, 

1998:889; L. Aguilar-Rosas et al., 2000:131; CONANP, 2012:138; 

Pacheco-Ruíz and Zertuche-González, 2002:468; Riosmena-Rodríguez 

et al., 2005a:33; Pacheco-Ruíz et al., 2008:211.

Ceramium affine var. originale E. Y. Dawson, 1950c:133, nom. superfl.; 

González-González et al., 1996:185.

Algae epiphytic or entangled with other algae, 4–6 mm 

high, main axis 20–35(–42) μm in diameter at base; branching 

irregularly subdichotomous, at intervals of 10–12 axial cells; 

corticated only at the nodes; branch apices straight to slightly 

incurved; proliferous branches uncommon; attached by rhizoids 

developed from periaxial and cortical cells. Periaxial cells number 4(–5), each periaxial cell cuts off 2 acropetal cortical initials. 

The second initial may be slightly larger than the first and is 

laterally displaced. Both initials may produce 1(–2) rounded cells 

acropetally, forming a very narrow cortical node usually only 

(1–)2–3 cells tall. No basipetal cortical initials or filaments develop. Internodes long and narrow, usually 3–4(–6) times longer 

than wide, 30–40 μm in diameter in lower portion, 24–28 μm in 

upper portion; becoming shorter in length toward apex.

Tetrasporangia tetrahedrally divided, oblong, projecting and 

naked, 27–45 μm in diameter; borne abaxial, usually single, or 

occasionally with 2 per node. Tetrasporangia are issued from periaxial cells. Cystocarps unknown in Gulf of California collections. 

Spermatangia forming a layer of tiny colorless cells beginning on 

one side of a cortical band and later completely covering the band.

Habitat. Epiphytic on various algae; shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Punta Los Frailes; Puerto Refugio, Isla Ángel de la Guarda; 

Nayarit to Jalisco. Eastern Pacific: southern California to Bahía 

Magdalena, Baja California Sur; Isla Guadalupe; Ecuador. Western Pacific: Japan; Korea (Y.-P. Lee, 2008; H.-S. Kim, 2012). 

Type Locality. Epiphytic on Codium simulans; Isla 

Guadalupe, off Baja California, Pacific Mexico.

Remarks. Although cystocarps are unknown in the 

Gulf Ceramium affine var. affine, in specimens from California, 

they were reported to be 100–120 μm in diameter, with large 

carposporangia (Abbott and Hollenberg, 1976), and in the Japanese C. affine, cystocarps were described as being surrounded 

by 3–4 involucral branchlets (Itono, 1977a). Specimens tentatively identified as Ceramium affine were also reported from the 

Galápagos Islands (Taylor, 1945, as “Ceramium affine, prox.”). 

Barros-Barreto et al. (2006: 912, tbl.3, figs. 2, 4a–h), using morphological and molecular data, have reported C. affine in the 

Western Atlantic from Brazil.

Ceramium affine var. peninsularis E. Y. Dawson

FIGURE 76

Ceramium affine var. peninsularis E. Y. Dawson, 1950c:132, pl. 2: figs. 16, 

17; 1961b:439; 1962a:51, pl. 17: figs. 9, 10; Huerta-Múzquiz and 
NUMBER 96 • 175

Tirado-Lizárraga, 1970:129; Huerta-Múzquiz, 1978:340; GonzálezGonzález et al., 1996:185.

Algae 10–12 mm high, subdichotomously branched at intervals of (8–)12–18 axial cells, with occasional adventitious 

branches; main axes cylindrical, 60–110 μm in diameter near 

base, tapering abruptly the last several segments to the apex; apices straight to slightly incurved. Axes attached by unbranched 

rhizoids with blunt tips or multicellular digitate pads. Axes corticated only at the nodes, with narrow cortical bands of only 2–3 

tiers of cells. Internodes elongate; mostly (4–)6–8 times as long 

as broad; below (up to 450 μm long), diminishing in size toward 

the upper portions of the thallus. Periaxial cells number 4; each 

cuts off 2 acropetal cortical initials; the second cortical cell initial 

is larger than the first and is displaced laterally to one side of 

the periaxial cell (resembling a pseudoperiaxial cell). These laterally directed acropetal cells are slightly smaller than the periaxial 

cells and often wedge shaped, interposed between the periaxial 

cells and regularly produce 1 acropetal cell. The cortical band 

lacks basipetal initials and all basipetal filament development.

Tetrasporangia oblong, up to 60 μm long, 30–50 μm in diameter; protruding, naked, each within a hyaline envelope; 1 to 

several borne irregularly secund at a node. Cystocarps, to 150 

μm in diameter, are surrounded by several involucral branches. 

Spermatangia clusters covering the surface of cortical cells, starting adaxially, and with time completely coating the nodal band.

Habitat. Epiphytic or entangled on various algae; 

intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de San Lucas. Eastern Pacific: Corona del Mar, southern 

California to Laguna Ojo de Liebre, Baja California; Golfo de 

Tehuantepec, Oaxaca to Chiapas.

Type Locality. Dredged from 4–6 m depth; Isla 

Concha, Laguna Ojo de Liebre (Scammon’s Lagoon), Baja California, Pacific Mexico.

Remarks. Ceramium affine var. peninsularis is the 

larger of the two varieties, almost twice the size of C. affine var. 

affine in all vegetative dimensions. Although both varieties are 

reported in the Gulf, only C. affine var. peninsularis was found 

in our Gulf collections.

Ceramium camouii E. Y. Dawson

Ceramium camouii E. Y. Dawson, 1944a:319, pl. 51: figs. 2, 3; 1950c:129; 

1957a:8; 1961b:440; 1962a:52, pl. 17: fig. 8, pl. 18: figs. 1, 2; Abbott 

and Hollenberg, 1976:594, fig. 533; Huerta-Múzquiz and MendozaGonzález, 1985:52; Mateo-Cid and Mendoza-González, 1992:21; 

Serviere-Zaragoza et al., 1993a:483; Mendoza-González et al., 1994:108; 

FIGURE 76. Ceramium affine var. peninsularis: A. Young nodes showing first acropetal cortical initial, and second laterally directed acropetal 

initial. B, C. Mature nodal cortication. D. Two filaments showing long internodes and short nodes, 2(–3) cells high (A–D, JN-4002, US Alg. 

Coll. microscope slide 8702).
176 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

González-González et al., 1996:185; Silva et al., 1996b:233; Mateo-Cid 

et al., 2000:66; L. Aguilar-Rosas et al., 2000:131; CONANP, 2002:138.

Algae up to 3–4 mm high, thin and delicate, 30–60(–80) μm 

in diameter, corticated only at the nodes, with very short nodal 

bands of small cells (about 3 cell rows high). Axes sparingly 

subdichotomously branched, with straight, nonforcipate apices; 

cortical bands shorter than internodes, internodes long basally; 

attached by rhizoids issued 1 per node, with blunt tips or digitate 

attachment pads. Periaxial cells number about 4(–5), each cuts 

off 2 roundish acropetal cortical initials and 2 basipetal initials. 

The acropetal initials may produce 1 or 2 more cells acropetally, 

the terminal cells of the acropetal filaments occasionally bearing a slender hair. Sometimes the original 4 cortical initials may 

divide in half into more angular smaller cells.

Tetrasporangia 25–35 μm in diameter, surrounded by an 

open involucre; whorled about the nodes, giving tetrasporangial axes a tumid appearance (Dawson, 1962a). Cystocarpic and 

spermatangial thalli unknown in Gulf of California material.

Habitat. Epiphytic on or entangled with other 

algae, such as Centroceras and Polysiphonia, and in algal turfs; 

intertidal.

Distribution. Gulf of California: San Felipe; Isla 

Turner to Ensenada Bocochibampo (west of Guaymas); Bahía 

de Loreto to Punta Arena (north of Cabo Pulmo); Mazátlan, 

Sinaloa to Jalisco. Eastern Pacific: southern California to Bahía 

Todos Santos (near Punta Banda), Baja California; Rocas Alijos. 

Western Pacific: China.

Type Locality. Among other minute algae scraped 

from intertidal rocks; Isla Turner (Turners), off SE end of Isla 

Tiburón (Islas de la Cintura), Gulf of California, Mexico.

Ceramium caudatum Setchell et N. L. Gardner

FIGURES 77, 78C

Ceramium caudatum Setchell et N. L. Gardner, 1924:776, pl. 27: figs. 55–57; 

Dawson, 1944a:317; 1950c:134; 1959a:30; 1961b:440; 1962a:52 [in 

part, excluding C. avalonae], pl. 18: figs. 3, 4, pl. 19: fig. 7, pl. 20: 

fig. 1; 1966a:26; Dawson and Neushul, 1966:182; Huerta-Múzquiz 

and Tirado-Lizárraga, 1970:129; Abbott and Hollenberg, 1976:594 

[in part, excluding C. avalonae], fig. 534; R. Aguilar-Rosas, 1982:84; 

Stewart and Stewart, 1984:145; Huerta-Múzquiz and MendozaGonzález, 1985:52; Mendoza-González and Mateo-Cid, 1986:425; 

Mateo-Cid et al., 1993:48; Mateo-Cid and Mendoza-González, 

1994b:41; Mendoza-González et al., 1994:108; González-González et 

al., 1996:304; CONANP, 2002:138; L. Aguilar-Rosas et al., 2002:235; 

Pacheco-Ruíz and Zertuche-González, 2002:468; Hernández-Herrera 

et al., 2005:147; Pacheco-Ruíz et al., 2008:211.

Algae with erect and prostrate portions, 4–15 mm tall, 

nodal bands (70–)100–120(–200) μm in diameter, internodes 

80–300 μm long in lower portions, shortening upward to 20–30 

μm long; apices forcipate and slightly incurved. Nodal band 

with 5 periaxial cells; each producing 2 acropetal cortical initials; each initial producing several branched acropetal filaments 

of progressively smaller cells. Basipetal development of cortical 

band variable and lateral. Young cortical bands may be without 

any basipetal development, while in mature portions of axes, a 

cell may be cut off obliquely from the posterior portion of a 

periaxial cell, laterally to one or both sides of the periaxial cell. 

The ends of the oblique cells remain level with the ends of the 

periaxial cells (not below the periaxial cell), resulting in truncate 

cortical bands. In robust specimens the 2 oblique laterally placed 

cells may divide further.

FIGURE 77. Ceramium caudatum: A. Nodal cortication (JN-4904b, US Alg. Coll. microscope slide 5256). B. Spermatangia covering nodes (JN4400, US Alg. Coll. microscope slide 8709). C. Detail of mature nodal cortication (JN-4138b, US Alg. Coll. microscope slide 5223). D. Emergent tetrasporangia (JN-3289, US Alg. Coll. microscope slide 5211). 
NUMBER 96 • 177

Tetrasporangia 45–55(–60) μm wide, to 75 μm long, tetrahedrally divided; projecting and naked; borne abaxial and adaxial, solitary or often whorled at a node. In young stages some 

tetrasporangia are caudate in shape (with a tail-like appendage). 

Cystocarps 180–195(–270) μm in diameter; borne laterally off 

axes, with 2–5 involucral branches that can be long and straight; 

carposporangia to 55 μm long. Spermatangia forming a dense 

patch of minute cells, beginning on one side and then completely 

covering a nodal band.

Habitat. Epiphytic on Codium and other algae 

and epizoic on stalked hydroids and the black sea turtle (tortuga negra), Chelonia mydas agassizii (sometimes referred to as 

C. mydas Linnaeus or C. agassizii Bocourt; see Carr, 1984; Parham and Zug, 1996); occasionally intertidal to subtidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Puerto Peñasco; Isla San Jorge; Roca 

Rojo, Bahía Kino to Bahía Empalme (south of Guaymas); Bahía 

Concepción to La Paz; Mazátlan, Sinaloa to Jalisco. Eastern 

Pacific: California Channel Islands to Isla Guadalupe; southern 

California to Todos Santos, Baja California Sur; Golfo de Tehuantepec, Oaxaca; Costa Rica.

Type Locality. Floating among other algae; Eureka,

near La Paz, Baja California Sur, Gulf of California, Mexico.

Remarks. The pattern of the cortical bands of Ceramium caudatum varies greatly from upper to lower portions 

of axes as the corticating filaments develop. Dawson (1962a: pl. 

18: fig. 3) illustrates younger nodes, whereas the older nodes in 

larger specimens have additional basipetal/lateral development 

FIGURE 78. Species of Ceramium. A. Ceramium aduncum: Mature node with gland cells (darkly stippled) and naked exerted tetrasporangia

(JN-3191, US Alg. Coll. microscope slide 4763). B. Ceramium clarionense: Mature node and tetrasporangia with involucres (holotype, Mason75, UC). C. Ceramium caudatum: Nodal cortication (diagrammatic; periaxial cells darkly stippled).
178 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

with “the angular cells tending to extend down over the larger 

rounded cells” (Dawson, 1962a:52).

The Santa Catalina Island (California Channel Islands) Ceramium avalonae E. Y. Dawson (1949b; 1950c; 1960a; 1962a: 

pl. 20: fig. 1: type of C. avalonae) was later considered conspecific with C. caudatum by Dawson (1962a) and Abbott and Hollenberg (1976). However, Womersley (1978) observed the nodal 

cortical structures of the two were quite different and recognized 

them as separate species (see also Stewart and Stewart, 1984; 

González-González et al., 1996).

Ceramium clarionense Setchell et N. L. Gardner

FIGURE 78B

Ceramium clarionense Setchell et N. L. Gardner, 1930:170, as “C. clarionensis,” pl. 7: figs. 26–27; Dawson et al., 1960b:10 [in part]; PachecoRuíz and Aguilar-Rosas, 1984:73; Serviere-Zaragoza et al., 1993a:483; 

R. Aguilar-Rosas and Aguilar-Rosas, 1994:523; Meneses, 1995:168, 

figs. 5–10; González-González et al., 1996:185 [in part; Pacific Mexico 

only]; Silva et al., 1996b:233; Abbott, 1999:269, fig. 75A–C; ServiereZaragoza et al., 2007:9; Pacheco-Ruíz et al., 2008:211; Pérez-Estrada 

et al., 2012:190.

Algae mostly erect, with creeping portions, to 9 mm high, 

axes 95–200 μm in diameter; axes corticated only at the nodes; 

internodes reduced to just a line near apices; branching subdichotomous, with intervals of 7–9 nodes between dichotomies 

in the distal region; numerous adventitious branches often present; apices forcipate and curved inward; attached by rhizoids 

originating from cortical cells. Axial cells spherical, cytoplasmic 

strand evident as a midline in axial cells throughout the thallus. 

Nodal bands with 7–8 periaxial cells; each periaxial cell issues 1 

small-celled acropetal corticating filament and 2 (rarely 3) largercelled basipetal filaments and also typically cuts off a pseudoperiaxial cell (totaling 7–8 at a node). Each pseudoperiaxial cell 

produces 2 acropetal and 1–2 basipetal corticating filaments. 

Cortical cells irregularly shaped, angular, or rounded. Cortical 

nodes sometimes more than twice as wide as tall.

Tetrasporangia cruciately divided, to 50(–65) μm in diameter; tetrasporangia borne within the upper half of cortical node, 

initially abaxial, at maturity may become whorled; cortical cells 

issue 3- to 4-celled involucres that subtend each tetrasporangia, 

bloating the node. Carposporangial thalli irregularly branched; 

cystocarps surrounded by up to 6 involucral branchlets. Spermatangia cover cortical surface cells in distal portions of the 

thallus.

Habitat. Epiphytic on larger algae; intertidal to 

subtidal.

Distribution. Gulf of California: Bahía de La Paz 

(Huerta-Múzquiz and Mendoza-González, 1985); Nayarit to 

Jalisco. Eastern Pacific: Rocas Alijos; Isla Clarión (Islas Revillagigedo). Central Pacific: Hawaiian Islands. 

Type Locality. Growing on Codium, Isla Clarión, 

Islas Revillagigedo, Pacific Mexico.

Remarks. Study of northern Gulf of California “Ceramium clarionense” sensu Dawson (1962b) showed specimens 

deposited in US Alg. Coll. were actually C. aduncum (see also 

Meneses, 1995, and Remarks under Ceramium aduncum). Thus, 

other records of Gulf of California “C. clarionense” that may be 

based on the interpretation of Dawson (1962a) and deposited in 

other herbaria (e.g., Huerta-Múzquiz and Mendoza-González, 

1985) should be reexamined before the presence of C. clarionense in the northern Gulf of California can be confirmed. 

Using morphological and molecular analyses Barrios-Barreto et 

al. (2006) have reported Ceramium clarionense in the Western 

Atlantic from Brazil.

Ceramium codicola J. Agardh

Ceramium codicola J. Agardh, 1894:23; Setchell, 1905:60; Kylin, 1941:29; 

Smith, 1944:326, pl. 84: fig. 1; Dawson, 1945d:59; 1950c:117, pl. 1: 

fig. 6; Dawson et al., 1960b:6; Dawson, 1961b:440; 1962a:54, pl. 19: 

figs. 5, 6, pl. 20: fig. 5; Abbott and North, 1972:75; Abbott and Hollenberg, 1976:600, fig. 543; L. Aguilar-Rosas, 1981:94; Pacheco-Ruíz 

and Aguilar-Rosas, 1984:73; Stewart and Stewart, 1984:145; HuertaMúzquiz and Mendoza-González, 1985:52; Mendoza-González and 

Mateo-Cid, 1985:26; Scagel et al., 1989:163; R. Aguilar-Rosas et al., 

1990:125; Stewart, 1991:129; González-González et al., 1996:185; 

Cho et al., 2002a:557, figs. 57–79.

Ceramium codiophilum Setchell et N. L. Gardner, 1937:89 [as “C. codiophila”], pl. 8: figs. 23, 24; Dawson, 1944a:318 [in part]; 1951:53; 

González-González et al., 1996:186.

Algae epiphytic on Codium; mostly erect, up to 1.8 cm tall, 

branching pseudodichotomously; axes completely corticated, 

with short, forcipate, incurved apices; attached by rhizoids produced by both periaxial and cortical cells in the basal portions 

of erect axes; rhizoids pigmented, unbranched, multicellular and 

with distinctive bulbous tips. Periaxial cells number 5–6, and 

surround the distal end of nodes; each periaxial cell cuts off 5 

cortical initials that produce the corticating filaments that form 

the cortex. First 2 cortical initials are cut off from the anterior 

end of a periaxial cell and grow acropetal cortical filaments; second 2 initials are cut off from the posterior end and grow basipetal cortical filaments; a fifth cortical initial is issued on the 

outside surface of a periaxial cell. The thallus is completely corticated throughout.

Tetrasporangia spherical, 35–40(–50) μm in diameter; embedded, scattered, or whorled in more or less swollen axes. Cystocarps surrounded by involucral branchlets; borne upper 2–3 

dichotomies of branches. Spermatangia unknown.

Habitat. Epiphytic on Codium; low intertidal to 

subtidal.

Distribution. Gulf of California: La Paz to San 

José del Cabo. Eastern Pacific: Alaska to California; Islas Todos 

Santos, Isla Guadalupe, Isla Cedros, and Islas San Benito, Baja 

California; Bahía San Bartolomé, Baja California Sur.

Type Locality. Epiphytic on Codium; Santa Cruz, 

Santa Cruz County, northern California, USA. Lectotype selected 

by Cho et al. (2002a:557).

Remarks. In the field, Ceramium codicola can often 

be recognized by the reddish brown patches it forms on host 

species of Codium. Sometimes resembling C. sinicola, the two 

are most easily differentiated by the nature of their attachment 
NUMBER 96 • 179

rhizoids. Ceramium codicola is attached to its specific host Codium by pigmented rhizoids with inflated to bulbous ends.

Ceramium equisetoides E. Y. Dawson

FIGURE 79A–C

Ceramium equisetoides E. Y. Dawson, 1944a:320, pl. 51: fig. 1; 1950c:128; 

1957c:21; 1961b:440; 1962b:55, pl. 19: fig. 4; 1966a:27; Abbott 

and Hollenberg, 1976:595, fig. 536; Mendoza-González and MateoCid, 1985:26; Huerta-Múzquiz and Mendoza-González, 1985:52; 

Ortega et al., 1987:74, pl. 6: fig. 27, pl. 7: figs. 28–30; Mateo-Cid 

and Mendoza-González, 1992:21; Mateo-Cid et al., 1993:48; MateoCid and Mendoza-González, 1994b:41; Mendoza-González et al., 

1994:108; González-González et al., 1996:186; Mateo-Cid et al., 

2000:66; CONANP, 2002:138; Mateo-Cid et al., 2006:56; Bernecker, 

2009:CD-Rom p. 64; Fernández-García et al., 2011:60; Pérez-Estrada 

et al., 2012:191.

Ceramium sp. of Setchell and Gardner, 1924:778: pl. 29: figs. 70, 71.

Algae up to 15 mm high, axis 50–100 μm diameter; with 

erect and prostrate axes; erect axes branching subdichotomously, 

apices forcipate or undivided; with numerous adventitious nonforcipate branches; corticated only at the nodes, except near 

apices of tetrasporangial axes; rhizoids arise from cortical and 

periaxial cells of prostrate axes, ending in digitate attachment 

discs or blunt tips. Internodes are long, to 300 μm basally, shortening up right near the apices where several nodes are often 

clumped closely together. Periaxial cells number 4–5, each divides off 4 cortical initials; 2 acropetal initials that branch and 

generate ascending filaments of 1–2 small cells long; and 2 basipetal initials that each cut off a cell basipetally. Basipetal and 

acropetal filaments about equal in length. Cortical bands truncate on both upper and lower edges, cells often rectangular on 

lower border of bands.

Tetrasporangia 30–40 μm in diameter, immersed in the 

cortex in terminal portions of main and lateral branches. Tetrasporangial axis nonforcipate and often slightly enlarged with 

internodes abruptly reduced, usually a single whorl of tetrasporangia at each node, at tip tapering quickly to apex; 1–3 tetrasporangia may be produced by a periaxial cell. Cystocarps 

lateral, surrounded by several involucral branchlets. Spermatangia minute cells, completely covering surface cortical cells in terminal portions of axes.

Habitat. Epiphytic on or entangled with other algae; 

intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Punta Arena (“Punta Arenas”; north of Cabo Pulmo); Laguna 

Agiabampo; Mazátlan, Sinaloa to Nayarit. Eastern Pacific: Newport Harbor, southern California, to Todos Santos, Baja California Sur; Costa Rica.

Type Locality. Puerto San Carlos, near Guaymas, 

Sonora, Gulf of California, Mexico.

Ceramium hamatispinum E. Y. Dawson

FIGURE 79D–G

Ceramium hamatispinum E. Y. Dawson, 1950c:122, pl. 3: figs. 20–22; 

1961b:440; 1962a:57, pl. 22: figs. 2–4; Hollenberg, 1968d:75, fig. 

2; Mendoza-González et al., 1994:108; González-González et al., 

1996:187; Abbott, 1999:275, figs. 77A(holotype)–B; Fernández-García 

et al., 2011:65.

Axes erect or decumbent, to about 10 mm tall and up to 130 

μm in diameter; subdichotomously branched in upper portions, 

apices circinate (incurved) (Figure 79D, E). Axes corticated only 

at the nodes, cortical bands up to 50 μm long. Periaxial cells 

number 6–7 at a node, each issue 1 acropetal and 2 basipetal 

short filaments. Pseudoperiaxial cells sometimes present, each 

bearing 2 acropetal and 1 basipetal filaments. Spines abundant 

and persistent, occurring throughout most of thallus; forming 

conspicuous whorls of (2–)4–6 spines around the distal part of 

cortical bands. Spines up to 50 μm long, of 3(–4) pigmented cells 

in a uniseriate row, and mostly recurved with an acute, hook-like 

tip (Figure 79F, G).

Reproduction not seen in Gulf specimens.

Habitat. Growing on rocks, sometimes on crustose 

corallines, or entangled with other algae; intertidal.

Distribution. Gulf of California: Bahía San Carlos; Mazátlan, Sinaloa to Nayarit. Eastern Pacific: Costa Rica. 

Central Pacific: Hawaiian Islands.

Type Locality. Intertidal; Miramar, south of San 

Blas, Nayarit, Gulf of California, Mexico.

Remarks. A new record for the northern Gulf of 

California, Ceramium hamatispinum was identified among species of Gayliella (EYD-11019a) and Polysiphonia, all collected 

from the shallow inner lagoon at Bahía San Carlos and mixed 

on the same microscope slide (EYD-11019b; US Alg. Coll. microscope slide 492). Ceramium hamatispinum as reported in the 

western Pacific from China may be a different species. Illustrations of Zheng et al. (2001; fig. 23:1–6) show its nodes with 

short, single-celled spines and straight branch apices; lacking the 

multicelled spines with recurved hook-like apices and incurved 

branch apices of C. hamatispinum.

Ceramium horridulum P. C. Silva

FIGURE 80

Ceramium horridulum P. C. Silva, 1972:204.

Ceramium horridum Setchell et N. L. Gardner, 1924:777, nom. illeg. [a later 

homonym of Ceramium horridum Meneghini, 1844a:184], pl. 26: figs. 

49, 50, pl. 79; Dawson, 1944a:318; 1950c:116; 1961b:440; 1962a:58, 

pl. 23: fig. 4; 1963c:12; R. Aguilar-Rosas and Machado-Galindo, 

1990:188; R. Aguilar-Rosas et al., 1990:125; González-González et 

al., 1996:187; CONANP, 2002:138; Pacheco-Ruíz and ZertucheGonzález, 2002:468; Pacheco-Ruíz et al., 2008:211.

Ceramium pacificum sensu Norris, 1973:15, pl. 6 [non Ceramium pacificum

(Collins) Kylin, 1925:61].

Algae relatively large, mostly erect, to 6–8(–18) cm tall, 

main axes in basal portions up to 625 μm in diameter (sometimes axes narrowing at nodes), gradually tapering to forcipate 

apices; branched subdichotomously, with 0–5 short branchlets 

whorled around a segment in middle and lower portions of 

axes, base of branchlets up to 210 μm in diameter; spines frequent with 1- to 2-celled spines terminating both main axes and 

short lateral branchlets. Periaxial cells number about 9. Axes 
180 • SMITHSONIAN CONTRIBUTIONS TO BOTANY
NUMBER 96 • 181

completely corticated by small angular cells, segments slightly 

separated only near apical region; cortication thin. Axes with 

predominantly basipetal cortication, basipetal filaments long, 

branched, cells in irregular longitudinal rows, acropetal cortical filaments shorter, covering a smaller portion of axial filament cell.

Tetrasporangia about 30–40 μm in diameter; immersed 

in the cortex, irregularly arranged, making an imprecise band 

around nodes of both main axes and short whorled branchlets. 

Whorled branchlets bearing cystocarps slightly wider (240–330 

μm in diameter at base) and longer than vegetative branchlets. 

Cystocarps up to 360 μm in diameter, usually only one per 

branchlet, gonimolobes surrounded by several (3–4) short, wide 

(140–180 μm diameter at base) involucral branches, with spines. 

Spermatangial thalli remain unknown in this species.

Habitat. On rocks and possibly entangled with 

other algae; subtidal, dredged from 4–32 m depths.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda to Guaymas; Los Mangles, Isla Carmén 

to Canal de San Lorenzo, off southern end of Isla Espíritu Santo. 

Eastern Pacific: Islas Todos Santos (off Ensenada), Baja California; Galápagos Islands (Dawson, 1963c).

Type Locality. Cast ashore among other algae; 

Guaymas, Sonora, Gulf of California, Mexico.

FIGURE 80. Ceramium horridulum: A. Habit (JN-5310, US Alg. Coll.-217345). B. Detail of one of the short branchlets radially arranged 

around axes, with several 2-celled spines (JN-5310, US Alg. Coll. microscope slide 8703).

FIGURE 79. (Opposite) A–C. Ceramium equisetoides: A. Tetrasporangial axes. B. Mature cortication pattern. C. Tetrasporangia immersed in 

cortex near terminal portions of axes, with internodes abruptly reduced (A–C, JN-3178e, US Alg. Coll. microscope slide 4666). D–G. Ceramium 

hamatispinum: D. Upper branch with incurved apices. E. Habit, showing characteristic spines whorled on nodes. F. Portion of axis with longer 

internodes. G. Detail of cortical node with multicellular spines with recurved tips (D–G, EYD-11019b, US Alg. Coll. microscope slide 492).
182 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Remarks. Among the Gulf species of Ceramium, C.

horridulum is readily recognized by its large size and numerous 

short branchlets radially arranged about the axes and adorned 

with spines. Cystocarpic specimens were found and are described 

above for the first time for this species (23 m depth from Roca 

Blanca, Puerto Refugio, Isla Ángel de la Guarda; JN-5805, US 

Alg. Coll. microscope slide 10,132).

In habit Ceramium horridulum bears a strong resemblance 

to C. pacificum but differs in several features. Ceramium horridulum has about 9 periaxial cells encircling a cortical band, 

and 1- to 2-celled spines terminal and along the main branches 

and the short lateral branchlets, whereas C. pacificum usually 

has cortical bands with (5–)6–7 periaxial cells, and spines are 

not mentioned in most descriptions (i.e., Dawson, 1962a; Cho 

et al., 2002a; Carlile et al., 2010). However Abbott and Hollenberg (1976) noted 1 or 2 short spines occasionally at apices of C. 

pacificum from California. The arrangement of the adventitious 

branchlets in middle to lower portions of the axes also differs: 

the axes of C. horridulum usually bear several, short branchlets (mostly 3–5), similar in length, in whorls around a segment; 

whereas in C. pacificum the adventitious branchlets are longer, 

usually of assorted lengths, and not whorled but more openly 

radially-arranged along numerous segments. Molecular evidence 

would help to determine the phylogenetic positions of these two 

morphologically similar species and their relationship to species 

in the “C. sinicola-complex” sensu Cho et al. (2003a).

Ceramium howellii Setchell et N. L. Gardner

FIGURE 81

Ceramium howellii Setchell et N. L. Gardner, 1937:88, pl. 6: fig. 14; Dawson, 

1957a:4; 1961b:440; 1962a:58, pl. 21: fig. 1, pl. 22: fig. 1; Stewart and 

Stewart, 1984:145; González-González et al., 1996:187.

Algae of both erect and prostrate portions, up to 15 mm 

tall; axes up to 650 μm in diameter, sparsely and irregularly 

branched. Erect axes with mostly short branches; branch apices 

nonforcipate, adaxially curved or “hooked.” Axial cells shorter 

than broad, with a cytoplasmic strand usually visible forming 

a midline; completely corticated by a thin, mostly single layer 

of small, irregularly arranged, angular cells (4–)7–12 μm in diameter. Periaxial cells number 10; larger, rounder, and slightly 

recessed below the thin layer of outer cortical cells.

Tetrasporangia 30–45 μm in diameter; irregularly scattered 

and embedded in the cortex of both main and lateral branches; 

sometimes aggregated into indistinct bands, tetrasporangial axes 

FIGURE 81. Ceramium howellii: A. Axial filament nearly completely corticated and developing branch with incurved tip. B. Branches with 

incurved tips. C. Tetrasporangia immersed in cortex (A–C, JN-5464, US Alg. Coll. microscope slide 5271). D. Developing cortication near a tip 

(EYD-8425, US Alg. Coll. microscope slide 479). 
NUMBER 96 • 183

up to 850 μm in diameter. Cystocarps borne laterally; enveloped 

by several involucral branchlets. Spermatangia small, colorless 

cells covering cortex in upper portions of thallus.

Habitat. On rocks; intertidal to shallow subtidal, 

down to 8 m depths (dredged to 30 m; Dawson, 1962a).

Distribution. Gulf of California: Punta la Gringa, 

Bahía de Los Ángeles; Bahía Salinas, Isla Carmén. Eastern Pacific: Isla Guadalupe (off Baja California); Galápagos Islands.

Type Locality. On rocks, southeast side of Isla Fernandina (Narborough Island), Galápagos Islands, Ecuador.

Remarks. Ceramium howellii is now reported in the 

northern Gulf of California from Punta la Gringa, Bahía de Los 

Ángeles (JN-5464b, US Alg. Coll. microscope slide 5271). Apparently rare or possibly overlooked, C. howellii in the northern 

Gulf is known only from this one collection. Its Gulf distribution 

is extended northward from Isla Carmén in the southern Gulf 

(Dawson, 1962a).

Ceramium interruptum Setchell et N. L. Gardner

FIGURE 82

Ceramium interruptum Setchell et N. L. Gardner, 1924:775, pl. 26: fig. 47; 

Cho et al., 2003a:778, figs. 1a–j, 2a–i. 

Ceramium sinicola var. interruptum (Setchell et N. L. Gardner) E. Y. Dawson, 

1944a:316; Hollenberg, 1948:158; Dawson, 1950c:119; 1959a:30; 

1961b:441; 1962b:65, pl. 27: fig. 8; 1966a:27; González-González et 

al., 1996:189. 

Algae usually epiphytic; of both creeping and erect portions, 

up to 1.5 cm tall, attached to host by branched rhizoids with 

blunt or digitate ends; erect axes branched pseudodichotomously, 

with 7–11 segments between branching points; apices forcipate 

FIGURE 82. Ceramium interruptum: A. Tetrasporangial axis cortication interrupted above the dichotomy, and tetrasporangia immersed 

in the cortex (JN-4201, US Alg. Coll. microscope slide 4788). B. Cortical pattern with cortication interrupted above dichotomy. C. Prostrate axis showing numerous rhizoids issued by periaxial and cortical cells of two nodes. D. Spines at apices (B–D, JN-4404, US Alg. Coll. 

microscope slide 4794). 
184 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

and incurved with occasional abaxial multicellular spines; axes 

mostly completely corticated, except at the first internode above 

a dichotomy where the axial filament cell is uncorticated, and 

incomplete cortication (internodes present) in lower and prostrate portions of thalli. Axial filament cells in the upper portions 

spherical to ovoid, becoming more cylindrical below. Periaxial 

cells number 7–9; each periaxial cell obliquely cuts off 4 cortical 

filament initials; 2 initials from the anterior end of a periaxial cell 

form acropetal filaments, and 2 initials from the posterior end 

form basipetal filaments. Mature acropetal and basipetal corticating filaments up to 10–13 cells long. Rhizoids issued from 

both periaxial and cortical cells of prostrate axes, uniseriate and 

multicellular, mostly ending in muticellular digitate pads. Gland 

cells, 10–15 μm in diameter, may develop on cortical filaments.

Tetrasporangia tetrahedrally divided, 46–56 μm long by 

35–50 μm in diameter, immersed in the cortex, in distal portions 

of thallus. Tetrasporangia appear whorled in a ring at the nodes, 

produced by the periaxial cells; tetrasporangia production continuing through several axial dichotomies, and in more proximal portions, tetrasporangia additionally issued by inner cortical 

cells and appear scattered or in several whorls per segment. 

Cystocarps subspherical, 163–287 μm long by 202–302 μm in 

diameter; borne in upper portions of a thallus, surrounded by 

5–7 incompletely corticated involucral branchlets. Spermatangia 

colorless, elliptical to spherical cells 3–5 μm × 2–4 μm; initially 

develop on adaxial side and later cover the cortical node.

Habitat. Epiphytic on various algae, including species of Codium, Gelidium, Laurencia, and articulated coralline 

algae; mid-intertidal tide pools to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco; 

Isla Coronado (Isla Smith), Bahía de Los Ángeles; Bahía Agua 

Verde to El Tecolote, Bahía de La Paz. Eastern Pacific: Orange 

County, southern California.

Type Locality. Eureka, near La Paz, Baja California Sur, Gulf of California, Mexico. 

Remarks. Recent studies of the Ceramium sinicola

complex that included C. sinicola var. interruptum (Cho et al., 

2003a) revealed it to be a distinct species, and C. interruptum

was reinstated on the basis of morphological and molecular data. 

Ceramium interruptum differs from the similar-looking species, 

C. sinicola and C. codicola, by its interrupted cortication above 

branching points, the issuing of only four cortical filament initials per periaxial cell, and its frequent creeping habit. 

Ceramium mazatlanense E. Y. Dawson

FIGURE 83

Ceramium mazatlanense E. Y. Dawson, 1950c:130, pl. 2: figs. 14, 15; 

1954a:6; 1957c:21; 1959d:4 [with a query]; 1961b:440; 1962a:59, pl. 

23: figs. 1, 2; Schnetter and Bula-Meyer, 1982:153, pl. 25: figs. E–K, pl. 

27: fig. B; Mendoza-González et al., 1994:108; González-González et 

al., 1996:187; Abbott, 1999:278, figs. 78C,D; López et al., 2004:11; 

Bernecker, 2009:CD-Rom p. 65; Fernández-García et al., 2011:61.

Ceramium macilentum sensu Serviere-Zaragoza et al., 2007:9 [non Ceramium macilentum J. Agardh, 1894:15].

Algae with both prostrate and erect portions, mostly 3–10 

mm tall, corticated only at the nodes, with relatively short cortical bands, about 25–30(–50) μm high; erect axes 70–120(–150) 

μm in diameter (cortical bands 2–3 times as wide as tall); branching subdichotomously; apices forcipate and incurved; prostrate 

axes attached to substrate by uniseriate rhizoids of several cells. 

Periaxial cells number 5(–6), most periaxial cells laterally cut off 

a pseudoperiaxial cell, resulting in a ring of up to 10(–12) wedgeshaped (rounded- triangular in surface view) cells at a node (i.e., 

5(–6) periaxial cells with 5(–6) pseudoperiaxial cells between 

them), periaxials usually with narrow ends of cell facing distally 

(upward), and pseudoperiaxials with their narrow ends facing 

downward. Each periaxial cell cuts off an acropetal cortical initial that produces a small-celled ascending filament, 2–4 cells 

long; each pseudoperiaxial cell usually produces 1 acropetal filament (2–4 cells long) and occasionally 1 basipetal initial (appears 

lateral). In some specimens corticating filaments may be mostly 

lacking, leaving only periaxial and pseudoperiaxial cells to form 

the node. Nodal bands (1–)2–4(–5) cells high, with smaller cells 

at the distal end of the node and larger cells below and beneath 

them. Internodes elongate in lower parts of thallus.

Tetrasporangia cruciately divided, spherical, (30–)35–50(–

65) μm in diameter (occasionally exceeding the cortical band 

length); issued from periaxial cells; tetrasporangia partially surrounded by a cortical envelope (i.e., covered by corticating cells 

and a projecting lax involucre of branched cortical filaments). 

Tetrasporangia borne abaxial, singly or up to several in a group, 

in a prominent series on successive nodes in upper portions of 

thalli; in some specimens tetrasporangia may be whorled at 

node, causing axis to appear tumid. One cystocarp surrounded 

by 2–3 involucral branchlets, 1 cystocarp per node, often in a 

short series on the abaxial side. Spermatangia small, colorless 

cells covering cortical surface cells of fertile bands. 

Habitat. Epiphytic on larger algae; mid to low intertidal.

Distribution. Gulf of California: Bahía Kino to 

Ensenada de San Francisco (vicinity of Guaymas); Mazatlán, 

Sinaloa. Eastern Pacific: Isla San Benedicto (Islas Revillagigedo); 

Guerrero; El Salvador; Costa Rica; Colombia; Clipperton Island 

(?). Central Pacific: Hawaiian Islands. Western Pacific: China.

Type Locality. Epiphytic on Codium; small reef 2 

miles (3.22 km) north of Mazatlán, Sinaloa, Gulf of California, 

Mexico. 

Remarks. Dawson (1954a) commented that the numerous hairs on the cortical bands of Ceramium mazatlanense reminded him of Trichoceras pubescens Kützing (1862: pl. 85: figs. 

d–r; =Ceramium fastigiatum var. pubescens (Kützing) Piccone) 

and suggested it should be reexamined. However, since then, 

Dawson (1962a) and others have accepted C. mazatlanense as 

being a distinct species (e.g., Meneses, 1995; Silva et al., 1996a; 

Abbott, 1999; Zheng et al., 2001; John et al., 2003, 2004). 

Although South and Skelton (2000) later placed Ceramium 

mazatlanense in synonymy with C. macilentum J. Agardh (1894), 

most have keep them separate (e.g., Zheng et al., 2001; John et 

al., 2004). Abbott et al. (2002) noted that specimens previously 
NUMBER 96 • 185

referred to “C. mazatlanense” from Vietnam (Dawson, 1954b; 

Phạm-Hoàng, 1969) were misidentified and actually were C. 

macilentum. Although the cortical patterns of the nodal bands 

are similar, C. mazatlanense may have a slightly greater basipetal 

(lateral) cortical development in mature nodes. For now the Gulf 

of California C. mazatlanense is recognized as distinct from the 

Australian C. macilentum until each can be tested and compared 

with molecular analyses.

Ceramium obesum E. Y. Dawson

FIGURE 84A

Ceramium obesum E. Y. Dawson, 1950c:119, pl. 1: figs. 7–9; 1961b:440; 

1962a:60, pl. 22: figs. 5, 6; González-González et al., 1996:187; 

Pacheco-Ruíz et al., 2008:211.

Algae mostly prostrate, with creeping axes, up to 2.2 cm 

in length; axes cylindrical, sturdy, and broad; 900–1100 μm in 

diameter (reduced in diameter at apices); infrequently and subdichotomously branched, but with many erect short secondary 

branches; apices forcipate, short, thick, strongly incurved tips; 

completely corticated, with thick cortex, composed of several 

cell layers, an inner layer of thick-walled cells, 25–100 μm in diameter, and a dense surface layer of small, anticlinally elongated 

cells, 15–25 μm long by 5–9 μm wide; attached to substratum by 

numerous small rhizoids produced from ventral surfaces.

Reproductive structures unknown.

Habitat. Growing in algal turfs among other algae 

and debris; intertidal.

Distribution. Gulf of California: Bahía Agua 

Dulce, Isla Tiburón.

Type Locality. Intertidal rocky shore; Bahía Agua 

Dulce, Isla Tiburón, Gulf of California, Mexico.

Remarks. An endemic species, Ceramium obesum is 

not well known and has not been recently collected.

Ceramium pacificum (Collins) Kylin

Ceramium rubrum var. pacificum Collins, 1913:125.

Ceramium pacificum (Collins) Kylin, 1925:61; Kylin, 1941:29; Smith, 

1944:326, pl. 83: fig. 3; Dawson, 1950c:120, pl. 4: fig. 30; t al., 

1960a:50, pl. 37: figs. 1, 2; 1961b:441; 1962b:61, pl. 23: fig. 3, pl. 

24: fig. 1; Abbott and Hollenberg, 1976:600, fig. 545; R. AguilarRosas, 1982:84; Pacheco-Ruíz and Aguilar-Rosas, 1984:73; Scagel et 

al., 1989:164; Sánchez-Rodríguez et al., 1989:44; Ramírez and Santelices, 1991:321; González-González et al., 1996:187; Pacheco-Ruíz and 

Zertuche-González, 2002:468; Cho et al., 2002a:565, figs. 117–140; 

Pacheco-Ruíz et al., 2008:211; Carlile et al., 2010:342, figs. 1–19; 

Jeong et al., 2013:440, fig. 1A–F.

Ceramium rubrum var. pacificum Collins in Hauck and Richter, 1889, nom. 

nud.: Exsiccate Phykotheka Universalis No. 302 [lectotype specimen 

of Ceramium rubrum var. pacificum Collins; see Carlile et al., 2010: 

fig. 1].

Ceramium rubrum var. pacificum Collins in Collins et al., 1901b, nom. nud.: 

Exsiccate Phycotheca Boreali-Americana No. 893.

Ceramium rubrum var. pacificum Collins in Setchell et N. L. Gardner, 1903, 

nom. nud.:345

FIGURE 83. Ceramium mazatlanense: A. Tetrasporangia with involucres giving tumid appearance. B. Two mature nodes, much wider than tall 

(A, B, EYD-11031, US Alg. Coll. microscope slide 512).
186 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Ceramium washingtoniense Kylin, 1925:62; Carlile et al., 2010:336, 342, fig. 

2 [type specimens].

Algae erect with prostrate portions, relatively large, up to 

18 cm high; axes about 350 μm in diameter; pseudodichotomously branched; 9–14 axial cells between branches; apices forcipate, inrolled. Axial cells spherical to cylindrical, completely 

corticated, except for slight gaps between segments near apices; 

cortication thin. Periaxial cells (5–)6–7 encircle a node; each cutting off 4 cortical initials that are spherical to ovoid and larger 

than the cells of the corticating filaments they generate. Basipetal 

growth predominates, with basipetal filaments usually longer 

than acropetal filaments. Outermost cortical cells angular and 

small, 10–14 μm in diameter. Small gland cells, 8–14 μm; cut 

off from cells at the ends of the acropetal corticating filaments. 

Adventitious lateral branchlets, numerous, relatively short and 

curved; develop from periaxial cells; radially arranged about the 

axis in middle to lower portions of thalli. Rhizoids, issued from 

large cortical cells, mostly rod-shaped with blunt tips.

Tetrasporangia cruciately divided, 42–60 μm in diameter 

(excluding sheath); develop from periaxial cells or occasionally 

from large cortical cells; immersed in the cortex, completely covered by cortical cells and forming 1 to 4 whorls about a node. 

Cystocarps nearly spherical, 280–350 μm in diameter; of 2–3 

gonimolobes and surrounded by 4–6 involucral branchlets (after 

Cho et al., 2002a). Spermatangia produced on spermatangial 

parent cells derived from surface cortical cells.

Habitat. On rocks or epiphytic; low intertidal to 

shallow subtidal, down to 4.5 m depths.

Distribution. Gulf of California: Bahía de La Paz. 

Eastern Pacific: Alaska to California; Punta María, Baja California; Chile. Western Pacific: Korea.

Lectotype Locality. Monterey, Monterey 

County, central California (Smith, 1944:326); lectotype specimen selected by Cho et al. (2002a:565; Carlile et al., 2010:342, 

fig. 1).

Remarks. Ceramium pacificum is reported in the 

southern Gulf of California from Bahía de La Paz (HuertaMúzquiz and Mendoza-González, 1985). Although superficially 

similar in appearance to C. horridulum, C. pacificum differs in its 

lack of 1- to 2-celled spines on main axes and on short radially arranged branchlets, number of periaxial cells, and arrangement of 

short, adventitious branchlets (see also Remarks under C. horridulum). Abbott and Hollenberg (1976) noted the occasional presence of short spines in apices of C. pacificum; however others do 

not mention spines in their descriptions (i.e., Kylin, 1925; Smith, 

1944; Dawson, 1962a; Cho et al., 2002a; Jeong et al., 2013).

FIGURE 84. Species of Ceramium. A. Ceramium obesum: Specimen from the type collection displaying 

stout forcipate apices, thick and complete cortication, and numerous rhizoids (after Dawson, 1962a: pl. 

22: fig. 5). B. Ceramium serpens: Erect axes with tetrasporangia above prostrate axes attached to substratum (after Dawson, 1962a: pl. 25: fig. 6).
NUMBER 96 • 187

Reexamination of the “C. pacificum” reported from Puerto 

Refugio, Isla Ángel de la Guarda (Norris, 1973) revealed it to be 

C. horridulum. Other Gulf of California specimens referred to 

“C. pacificum” need to be critically compared with C. horridulum and type locality Pacific C. pacificum to confirm its presence 

in the Gulf.

Ceramium paniculatum Okamura

FIGURE 85

Ceramium paniculatum Okamura, 1896:36, pl. 3: figs. 22, 23; 1921:114, 

122, pl. 179: figs. 8–16; 1936:737; Dawson, 1944a:319; 1950c:122; 

1959a:10, 30; 1960c:97; 1961b:441; 1962b:61, pl. 23: figs. 5–7; Nakamura, 1965:146, figs. 9, 10, pl. 2: fig. 5; Hollenberg, 1968d:75, fig. 

FIGURE 85. A–D. Ceramium paniculatum: A. Multicelluar spines near apices. B. Detail of multicellular recurved spines (JN-4539, US Alg. Coll. 

microscope slide 4258). C, D. Several examples of mature cortication pattern, one node with a persistent multicellular spine. E, F. Tetrasporangia develop first on one side then become whorled around nodes, each enfolded by an involucre of several cells, resulting in a tumid appearance

(A, C–F, JN-4396, US Alg. Coll. microscope slide 8704).
188 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

1; Itono, 1972:75; 1977a:32, 101, 263, figs. 13D1-7, 59F–G, 60D; 

Stewart and Stewart, 1984:145; Tseng, 1983:128, pl. 67: fig. 3; HuertaMúzquiz and Mendoza-González, 1985:52; González-González et al., 

1996:188; Yoshida, 1998:897, figs. 3-86F,G; Abbott, 1999:279, fig. 

78E; CONANP, 2002:138; López et al., 2004:11; Pacheco-Ruíz et al., 

2008:211; Fernández-García et al., 2011:61.

Algae of erect axes, up to 13 mm tall, above short prostrate 

portions; axes 120–150 μm wide; axial cells 240 μm long, 135 

μm wide in basal regions, tapering very slightly upward to tips; 

branching subdichotomous; branches occurring at intervals of 

6–11 axial filament cells, with few proliferous branches, mostly 

on the basal parts of erect axes and prostrate axes, arising from 

periaxial cells; corticated only at the nodes, internodes long 

below (up to 180 μm), decreasing to quite small above. Apices 

forcipate, often with a series of acute, (2–)3–4(–5)-celled straight 

or recurved spines, one per node, 20–50 μm long, arranged abaxially in upper parts of thallus. Multicellular spines deciduous, 

infrequent on nodes below. Periaxial cells at nodes of decumbent axes issue unbranched to sparingly branched attachment 

rhizoids. Periaxial cells number 6(–7); each cuts off 4 corticating 

initials, 2 from the anterior end of the periaxial cell and 2 from 

the posterior end. The top 2 initials form acropetal corticating 

filaments, 1–3 cells long, and 2 posterior initials cut off basipetal corticating filaments, 1–3 cells long. Acropetal and basipetal 

filament growth nearly equal. Nodal bands usually 5(–8) cells 

high (50–75 μm high), broader than tall, truncate on both upper 

and lower margins. Cortication appears mostly 1 cell layer thick, 

except along middle of node; corticating cells large in comparison with those of other Gulf Ceramium species; periaxial cells in 

middle of node largest and roundest (about 20 μm in diameter); 

ultimate acropetal cortical cells (along upper margin) smallest of 

node (about 8 μm wide); ultimate basipetal filament cells sometimes vertically elongate. Gland cells absent.

Tetrasporangia, 30–45 μm long, involucred by several bracteate cortical filaments, lower portions covered by corticating cells; 

1 to several tetrasporangia at a node, initially abaxial and then becoming whorled, causing nodal band to appear tumid. Cystocarps 

unknown in Gulf of California material. Spermatangia minute 

cells covering cortical cells in the upper portions of thalli.

Habitat. On rocks or epiphytic on other algae, often 

in tide pools; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas; Bahía de Loreto to Cabeza Ballena; Mazatlán, 

Sinaloa. Eastern Pacific: Isla Guadalupe (off Baja California); 

Guerrero to Oaxaca; El Salvador. Central Pacific: Hawaiian Islands. Western Pacific: Japan; China; Korea. 

Type Locality. Growing on Corallina; Kamahara, 

formerly Iwaki Province (along sea from Hitachi, Rikuzen, 

to Iwashiro; Rein, 1884), Tōsandō region (Okamura, 1896), 

Honshū Island, Japan.

Remarks. Although cystocarps are unknown in Ceramium paniculatum specimens from the northern Gulf, those from 

Japan (Okamura, 1921) are borne abaxially in a series on upper 

branches, consist of 2–5 gonimolobes (Itono, 1977a: fig. 59G) 

and are subtended by up to four short, involucral branchlets.

The habit of Gulf of California C. paniculatum differs from 

Korean material (H.-S. Kim, 2012: fig. 66A–D) in being shorter 

in thallus height, having shorter internode lengths in lower portions of thallus, and longer intervals between branches (often 

up to 11 axial cells). The cortical pattern of Japanese (Itono, 

1977a: fig. 13D4) and Korean C. paniculatum has shorter basipetal cortical filaments than those of Gulf specimens. However 

in mature lower portions, the cortical pattern of the Korean alga 

(H.-S. Kim, 2012: fig. 69C) has longer basipetal filaments and is 

somewhat similar to those of Gulf material. The nodes of Gulf of 

California C. paniculatum also differ in being truncate on both 

upper and lower margins, and some of the ultimate basipetal 

cells are slightly longer than wide (Figure 85C, D).

Ceramium periconicum T. O. Cho et Riosmena-Rodriguez

FIGURE 86

Ceramium periconicum T. O. Cho et Riosmena-Rodriguez, 2008:307, 

figs.1–49.

Algae in short tufts, with prostrate and erect axes, up to 3 

mm tall; axes slender, 45–75(–90) μm in diameter; corticated only 

at the nodes; nodal cortication to about 30(–40) μm high (3(–4) 

cells high). Apices forked and straight, unequal in length, branching pseudodichotomous and subsequently regularly alternate in 

mature specimens. Prostrate axes with long internodes; attached 

by uniseriate, multicellular rhizoids (originating from periaxial 

cells), often terminating in digitate pad. Periaxial cells 4–5 at a 

node; each cuts off 3 cortical initials; first 2 cortical initials divide 

off from the anterior end of the periaxial cell and develop the 

acropetal filaments, 2(–3) cells long; third cortical initial cut off 

by a vertical division through a periaxial cell and is directed laterally (only on one side); lateral initial situated between periaxial 

cells and does not divide further. Cortical bands lack basipetal 

filaments. Gland cells present or lacking; small, angular, 8–12 μm 

wide, borne at tips of acropetal corticating filaments.

Tetrasporangia tetrahedrally divided, up to 40 μm long by 

35 μm wide (not including hyaline sheath), naked, protruding; 

borne primarily abaxially in a series in upper portions of thalli, 

rarely whorled; each periaxial cell may produce up to 2 tetrasporangia. Mature cystocarps in upper portions of thallus, spherical, 

up to about 200 μm in diameter; with 2–3 gonimolobes subtended by 3–4 involucral branchlets (female reproductive structures described from Baja California Sur specimens; see Cho and 

Riosmena-Rodriguez, 2008). Spermatangial parent cells arise 

from cortical cells and produce 1–2 spermatangia terminally, 

initially developing on one side of nodal band and eventually 

covering whole band; spermatangia small colorless cells, 1–4 μm 

in diameter.

Habitat. In turfs; epiphytic on other algae, including 

Gelidium, Amphiroa, and Agardhiella, that grow on hard substrata and in tide pools; mid intertidal to shallow subtidal, down 

to 10 m depths (also dredged from 20 m).
NUMBER 96 • 189

Distribution. Gulf of California: Playa Las Conchas (Playa Estación), Puerto Peñasco to Isla la Ventana, Bahía 

de Los Ángeles; Bahía de La Paz to Bahía de San Lucas. 

Type Locality. 2–3 m depth; Punta Perico (north 

of Bahía de los Muertos), Baja California Sur, Gulf of California, 

Mexico. 

Remarks. A Gulf of California endemic species, Ceramium periconicum is now reported in the upper Gulf with its 

collection from Puerto Peñasco, Sonora (Cumpleaños Tidepool, 

Playa Las Conchas (Playa Estación): JN-3906c, US Alg. Coll. 

microscope slide 5218). Other northern Gulf collections, from 

Isla la Ventana, Bahía de Los Ángeles (JN-4436 and JN-4459, 

US Alg. Coll. microscope slide 5236), are also northward distribution extensions from Punta Perico, Baja California Sur. Some 

northern Gulf specimens have axes slightly wider in diameter (up 

to 90 μm), and no gland cells were observed at tips of acropetal 

cortical filaments. One specimen identified as C. periconicum, 

from Bahía de San Lucas (EYD-6851a, US Alg. Coll. microscope 

slide 557), shows the division of the third cortical initial from 

some periaxial cells slightly off vertical, tending toward oblique, 

but the third cortical initial is always laterally directed and does 

not divide further. 

Ceramium procumbens Setchell et N. L. Gardner

FIGURE 87

Ceramium procumbens Setchell et N. L. Gardner, 1924:772, pl. 27: figs. 51–

54; Dawson, 1944a:318; Hollenberg, 1948:158; Dawson, 1950c:128; 

1959a:30; Dawson et al., 1960b:11, 12, 13; Dawson, 1960a:51; 

1961b:441; 1962a:63, pl. 24: figs. 3, 4, pl. 25: figs. 1–3; 1966a:27; 

Dawson and Neushul, 1966:182; Itono, 1972:85; Abbott and Hollenberg, 1976:597, fig. 539; Itono, 1977a:33, 100, 198, 231, 266, figs. 

13G1-6, 15E–J, 37F–G, 50H,I, 58H–J, 59H; Huerta-Múzquiz and 

Mendoza-González, 1985:52; González-González et al., 1996:188; Yoshida, 1998:897; Mateo-Cid et al., 2000:66; Cho et al., 2001:45–52, 

figs. 1–28; CONANP, 2002:138; Pacheco-Ruíz and Zertuche-González, 

2002:468; Pacheco-Ruíz et al., 2008:211; Bernecker, 2009:CD-Rom p. 

65; Fernández-García et al., 2011:61; Nguyen et al., 2013:211.

Ceramiella procumbens (Setchell et N. L. Gardner) Díaz-Piferrer, 1969a:203.

Algae minute epiphytes; axes mostly prostrate, producing 

oppositely to irregularly arranged erect axes, 1–2(–3) mm high, 

40–100 μm in diameter; cortication incomplete. branching of repent axes and erect branches irregular, with short, erect adventitious branches; Axes attached to host by short uniseriate rhizoids 

with blunt tips or multicellular digitate pads, rhizoids issued by 

both periaxial and cortical cells. Apices of prostrate axes slightly 

FIGURE 86. Ceramium periconicum: A. Cortication pattern at nodes (EYD-6851a, US Alg. Coll. microscope slide 557). B. Protruding naked 

tetrasporangia. C. Cortication pattern, no basipetal cortical filament development, one cell cut off transversely (laterally) (B, C, JN-4436, US 

Alg. Coll. microscope slide 8705).
190 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

forcipate; apices of erect adventitious branches straight, undivided. Erect adventitious branches unilaterally issued by periaxial 

cells on the dorsal side of prostrate axes. Axial cells cylindrical, 

up to 150 μm long and to 60 μm in diameter in basal regions; 

decreasing in size toward the apex, and more spherical in shape. 

Corticated only at the nodes, cortical bands wider than tall. Internodes 60–105 μm long basally, becoming shorter toward the 

apex. Periaxial cells number 4 per axial cell; each periaxial cell 

cuts off 4 cortical initials, 2 are obliquely cut off from the anterior end and form acropetal corticating filaments, and 2 are cut 

off obliquely from the posterior end of the periaxial cell, producing basipetal corticating filaments. In mature bands acropetal 

filaments slightly longer (2–3 cells long) than basipetal filaments.

Tetrasporangia irregularly cruciately divided, 30–45(–50) 

μm in diameter; arranged in a whorl around a cortical band, 

on a number of bands in succession; a single tetrasporangium 

produced per periaxial cell; immersed in the cortex of terminal 

portions of clavate branches. Tetrasporangial branches of varying lengths, swelling to 85–180 μm in diameter to accommodate 

tetrasporangia; internodes shortened, cortical bands packed 

tightly together. Gametophytes dioecious. Cystocarps spherical, 

50–105 μm in diameter, surrounded by 2–4 involucral branchlets; 

and appear to be terminal on erect adventitious branches; several 

upper nodes of these branches broaden in diameter before the 

cystocarp. Carposporangia 22–30 μm in diameter. Spermatangia 

minute, colorless cells above spermatangial parent cells produced 

from cortical cells, covering and swelling terminal end (except 

apex) of erect adventitious branches (after Cho et al., 2001).

Habitat. Epiphytic on various algal hosts, including Laurencia, Gelidium, Grateloupia, and especially Amphiroa; 

mid intertidal to shallow subtidal, down to 8 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena. Eastern Pacific: Santa Cruz Island, Anacapa 

Island and Santa Catalina Island (California Channel Islands) to 

Punta Santa Rosaliita (“Punta Santa Rosalía”), Baja California; 

Isla Magdalena (Bahía Magdalena), Baja California Sur; El Salvador; Costa Rica. Western Pacific: Japan; Vietnam.

Type Locality. Epiphytic on Grateloupia prolongata; Isla Partida (off north end of Isla Espíritu Santo), Baja California Sur, Gulf of California, Mexico.

Ceramium serpens Setchell et N. L. Gardner

FIGURE 84B

Ceramium serpens Setchell et N. L. Gardner, 1924:775, pl. 27: fig. 58; 

Dawson, 1944a:318; 1949c:244; 1950c:129; 1957a:4, 5; 1961b:441; 

1962a:64, pl. 25: fig. 6; Abbott and Hollenberg, 1976:598, fig. 540; 

Itono, 1972:79, fig. 8; 1977a:33, 109, 198, figs. 13F1-2, 15A, 37H; 

Schnetter and Bula-Meyer, 1982:155, pl. 26: figs. A–C, pl. 28: fig. 

C; Huerta-Múzquiz and Mendoza-González, 1985:52; MendozaGonzález and Mateo-Cid, 1985:26; González-González et al., 

1996:188; Yoshida, 1998:898; Abbott, 1999:281, fig. 79C; PachecoRuíz et al., 2008:211.

Algae minute epiphytes; 3–4(–10) mm in height; main axis 

45–90 μm in diameter; creeping filaments give rise to sparsely 

branched erect axes; attached to host by rhizoids. Apices of erect 

axes nonforcipate or rarely branched, slightly curved. Corticated 

only at the nodes; internodes rather long (3–5 times nodal band 

height), except near the apex. Periaxial cells number 4 at a node; 

each cutting off 4 cortical initials, 2 from the anterior end and 2 

from the posterior end of the periaxial cell that initiate cortical 

filaments. The anterior pair branch once, forming acropetal filaments 2 cells long, and the posterior pair may not divide or may 

divide obliquely or transversely, forming basipetal filaments 2 

cells long. Gland cells absent.

Tetrasporangia cruciately divided, 25–35(–40) μm in diameter; usually solitary (rarely 2) at a node, distributed in a short 

series along upper portions of erect axes, protruding through the 

cortex, partially covered by acropetal corticating filaments. Cystocarps and spermatangia unknown.

Habitat. Epiphytic on larger algae; intertidal.

Distribution. Gulf of California: La Paz to Punta 

Palmilla. Eastern Pacific: Santa Catalina Island (California 

Channel Islands) to Baja California; Clipperton Island (Dawson, 

FIGURE 87. Ceramium procumbens: Branching pattern and tetrasporangia immersed in clavate branches (JN-4897, US Alg. Coll. 

microscope slide 8706).
NUMBER 96 • 191

1957a, with query); Costa Rica (Dawson, 1962a, with query); 

Colombia; Galápagos Islands (Dawson, 1957a, with query). 

Central Pacific: Hawaiian Islands; Marshall Islands; Palmyra 

Atoll. Western Pacific: Japan; China.

Type Locality. Epiphytic on Laurencia; La Paz, 

Baja California Sur, Gulf of California, Mexico.

Remarks. Although described from the southern 

Gulf, Ceramium serpens is not well known. The collection of 

gametangial thalli from the type locality, La Paz, and molecular 

testing of topotype material will be useful in elucidating its taxonomic status. Outside the Gulf of California, C. serpens has been 

rather widely reported: in the western Pacific, central Pacific, 

South Pacific, Western Australia (Huisman and Borowitzka, 

2003), and the Seychelles (Indian Ocean) (Silva et al., 1996a).

South and Skelton (2003) corroborated the interpretation of 

Millar (1990) and considered Fiji collections of C. serpens conspecific with Ceramium codii (H. Richards) Feldmann-Mazoyer 

(1938; basionym: Ceramithamnion codii H. Richards, 1901; 

type locality: Bermuda). It too has been widely reported: in the 

Atlantic from Florida to Brazil, the Caribbean Sea, Europe, and 

Africa, and in the Pacific off Japan, Korea, the Hawaiian Islands, 

Micronesia, and Chile (Guiry and Guiry, 2010) and Rapa Nui 

(Easter Island; Isla de Pascua; Santelices and Abbott, 1987). 

Morphological differences between “C. codii” from Korea and 

Bermuda type materials were observed by H.-S. Kim (2012). 

However, until molecular analyses are completed on those identified as “C. codii,” Cho and Fredericq (2006) restricted C. codii

to Bermuda and the Florida Keys, noting it is probably not as 

widespread in distribution as has been reported, and there may 

be up to 11 species in the “C. codii-complex.”

Ceramium sinicola Setchell et N. L. Gardner var. sinicola

FIGURE 88

Ceramium sinicola Setchell et N. L. Gardner, 1924:773, pl. 25: figs. 40, 41, 

pl. 75; Dawson, 1944a:315; 1950c:118, pl. 1: figs. 4, 5; 1957a:5, 8; 

1959a:30; Dawson et al., 1960b:12; Dawson, 1961b:441; 1962b:64, 

pl. 25: figs. 4, 5, pl. 27: figs. 6–8; Abbott and Hollenberg, 1976:602, 

fig. 546; L. Aguilar-Rosas, 1981:94; Schnetter and Bula-Meyer, 

1982:156, pl. 26: figs. D–F, pl. 27: fig. D; Pacheco-Ruíz and AguilarRosas, 1984:73; Stewart and Stewart, 1984:145; Huerta-Múzquiz 

and Mendoza-González, 1985:52; Mendoza-González and MateoCid, 1985:28; 1986:425; Ortega et al., 1987:75, pl. 8: figs. 34–36; 

Salcedo-Martínez et al., 1988:83; R. Aguilar-Rosas et al., 1990:125; 

Mateo-Cid and Mendoza-González, 1994b:41; González-González et 

al., 1996:188; Silva et al., 1996b:233; Mendoza-González and MateoCid, 1999:44, figs. 20–23; Mateo-Cid et al., 2000:66; Cruz-Ayala 

et al., 2001:191; Pacheco-Ruíz and Zertuche-González, 2002:468; 

CONANP, 2002:138; Cho et al., 2003a:778, figs. 3, 4; López et 

al., 2004:11; Serviere-Zaragoza et al., 2007:9; Pacheco-Ruíz et al., 

2008:211.

Ceramium bicorne Setchell et N. L. Gardner, 1924:773, pl. 28: fig. 64, pl. 74; 

Pacheco-Ruíz et al., 2008:211. 

Algae epiphytic, robust, (1–)3–5(–10) mm high; mostly 

erect axes, 120–250(–690) μm in diameter, often more slender 

basally, widening above, branching subdichotomous, at intervals 

of 6–8 axial segments, with frequent short proliferous branchlets 

above short prostrate axes; attached by multicellular rod shaped 

rhizoids, produced by periaxial and cortical cells, rhizoids with 

mostly blunt tips or occasionally multicellular digitate pads. 

Apices forcipate and slightly incurved, at times with 1 to several multicellular spines. Cortication coverage variable: almost 

completely corticated in some or internodes evident basally but 

barely discernable up higher on erect axes (i.e., cortication incomplete in basal portions and prostrate axes with internodes 

evident). Periaxial cells 7–8 at a node; each periaxial cell cuts 

off 5 cortical initials; first 2 initials cut off obliquely from the 

anterior end of the periaxial cell develop acropetal cortical filaments, each 5–7 cells long; second 2 initials are cut off obliquely 

from the posterior end of the periaxial cell and develop basipetal 

filaments, each 5–7 cells long; a fifth cortical initial issued on the 

outside face of a periaxial cell. Cortex composed of small angular cells, 5–7 μm in diameter; covering nearly all of the axial cell 

in the upper parts of mature erect axes, with a diminutive empty 

space separating segments.

Tetrasporangia tetrahedrally divided, spherical to ellipsoidal, (30–)45–55 μm in diameter; immersed in the cortex, 

and sporangial production may extend through several axial 

dichotomies; tetrasporangial axes may be enlarged, up to 690 

FIGURE 88. Ceramium sinicola: Nearly complete cortication covers 

axial filament with immersed tetrasporangia whorled at nodes (JN4584, US Alg. Coll. microscope slide 4798).
192 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

μm in diameter, occasionally with several short straight spines 

at the apices. Tetrasporangia in a whorl at a node in distal portions of the thallus when produced only by the periaxial cells 

(1 per parental cell); in middle regions tetrasporangia also produced by inner cortical cells with additional whorls of tetrasporangia within a segment. Cystocarps spherical, 150–350 μm in 

diameter; borne abaxial in upper portions of axes, surrounded 

by 4–6 short involucral branchlets with incomplete cortication. 

Spermatangia minute, colorless cells, 3–4 μm in diameter; form 

a dense layer over cortical cells in the upper portions of the thallus; initially adaxial, later encircling cortex (Cho et al., 2003a).

Habitat. Epiphytic on Codium, Laurencia, Tacanoosca, Amphiroa, and other, usually larger, algae; low intertidal 

to shallow subtidal.

Distribution. Gulf of California: Bahía Tepoca to 

Cabeza Ballena; Isla San Pedro Nolasco; Bahía Topolobampo; 

Laguna Agiabampo, Sonora-Sinaloa to Nayarit. Eastern Pacific: 

Santa Barbara, California to Todos Santos and Rocas Alijos, 

Baja California Sur; Islas Todos Santos and Isla Guadalupe, Baja 

California; Isla San Benedicto (Islas Revillagigedo); Jalisco to 

Guerrero; Colombia.

Type Locality. Bahía de Todos Santos, Ensenada, 

Baja California, Pacific Mexico.

Remarks. Ceramium sinicola var. sinicola is a frequently encountered epiphyte in the Gulf of California. Originally, 

Setchell and Gardner (1924a) described three similar-looking 

Gulf species (C. sinicola, C. interruptum, and C. johnstonii) on 

the basis of differences in degrees of their cortication. Dawson 

(1944a) reduced these species to taxonomic varieties of C. sinicola, as C. sinicola var. sinicola, C. sinicola var. interruptum,

and C. sinicola var. johnstonii. Abbott and Hollenberg (1976) 

did not recognized these varieties, noting that “large numbers 

of specimens will demonstrate a complete range of the cortication characters by which these varieties are distinguished,” thus 

reducing them to represent a single, variable, more broadly defined species. More recently, Cho et al. (2003a) resurrected one 

of the taxonomic varieties to specific status, C. interruptum, on 

the basis of phylogenetic analyses of its distinct DNA sequences 

as well as morphological features. Reports identifying “C. sinicola” from the Gulf of California and Pacific Mexico should be 

reexamined to verify that they are C. sinicola var. sinicola or 

possibly C. sinicola var. johnstonii or C. interruptum (see also 

Remarks under C. interruptum).

Ceramium sinicola var. johnstonii (Setchell et N. L. Gardner) 

E. Y. Dawson

Ceramium johnstonii Setchell et N. L. Gardner, 1924:774, pls. 76, 77.

Ceramium sinicola var. johnstonii (Setchell et N. L. Gardner) E. Y. Dawson, 

1944a:316; 1950c:119; 1961b:441; 1962a:65; González-González et 

al., 1996:189.

Algae 1–2(–3) cm tall, about 80 μm in diameter; subdichotomously branched; completely corticated, except in basal portions; 

cortical cells 7.0–10 μm in diameter, not arranged in rows; a slight 

separation between corticating segments can form a very narrow 

internodal space in upper portions of axes; apical cell very acute.

Tetrasporangia completely immersed in corticating layer; irregularly scattered in axes and more or less arranged in whorls 

in short lateral branches (only slightly swelling the branches). 

Cystocarps and spermatangia unknown in type material (Setchell and Gardner, 1924).

Habitat. Epiphytic on various algae; intertidal.

Distribution. Gulf of California: Bahía Tepoca to 

La Paz; Isla San Esteban and Isla San Pedro Mártir (Islas de la 

Cintura).

Type Locality. Isla San Pedro Mártir, Gulf of California, Mexico.

Remarks. Although similar to Ceramium sinicola

var. sinicola, the variety C. sinicola var. johnstonii differs morphologically in being completely corticated throughout the thallus except in the lowermost basal parts (Dawson, 1962a). The 

taxonomic status of Gulf of California C. sinicola var. johnstonii requires further investigation and comparative testing with 

Pacific Mexico C. sinicola var. sinicola, particularly with type 

locality (Ensenada, Baja California) material. The southern California C. sinicola was elucidated by Cho et al. (2003a), who also 

suggested that C. johnstonii may be conspecific.

Ceramium vagans P. C. Silva

Ceramium vagans P. C. Silva in Silva et al., 1987:56; Abbott, 1999:284, fig. 

80A–D; Abbott et al., 2002:305, fig. 8; López et al., 2004:11; ServiereZaragoza et al., 2007:9; Bernecker, 2009:CD-Rom p. 65; FernándezGarcía et al., 2011:61.

Ceramium vagabundum E. Y. Dawson, 1957b:121, nom. illeg., fig. 27e; 

1957c:22; 1961b:441; 1962b:66, pl. 27: fig. 5; Schnetter and BulaMeyer, 1982:157, pl. 26: figs. G,H, pl. 28: figs. A,B; González-González 

et al., 1996:189 [a later homonym of Ceramium vagabundum (Linnaeus) Roth, 1800:465; basionym: Conferva vagabunda Linnaeus, 

1753:1167, which is now Cladophora vagabunda (Linnaeus) C. Hoek, 

1963:144].

Ceramium sp. sensu Dawson, 1954c:6, pl. 4: fig. 2 [see Dawson, 1957c:22].

Algae of erect axes arising irregularly from prostrate axes; 

mostly less than 2(–5) mm high and 60–135(–165) μm in diameter; erect axes unbranched or sparingly subdichotomously to 

irregularly branched, with gradual taper to straight nonforcipate 

apices; attached to substrate by rhizoids issued by periaxial and 

cortical cells on ventral side of creeping axes. Corticated only at 

nodes, internodal space narrowing toward apices. Periaxial cells 

number 6–8; each cuts off 4 cortical initials, 2 acropetal and 2 

basipetal. Nodal bands in young stages 3 cell rows high. Each 

cortical initial produces 2 cells (that elongate then divide); each 

developing 2 cortical filaments several cells long. Along lower 

(proximal) margin of the nodes at the elongation stage (before 

division) the bottom row of elongate cells looks regularly parallel, then cells divide, and the row looks less regular, although 

nodal cortication remains truncate along bottom edge (upper 

margin also truncate). Acropetal and basipetal filament growth 

about equal, with round periaxial cells in middle of band with 

progressively smaller cells toward edges, ultimate cells angular, 

<10 μm. Mature nodal bands consist of 7–8 cell rows; bands 

about 1.5–2.0 times as wide as tall. Gland cells absent.
NUMBER 96 • 193

 Tetrasporangial axes swollen, 180–195(–250) μm in diameter; nodal bands closely arranged, forming tumid crowded area 

near terminal portion of axes. Tetrasporangia typically cruciately 

divided, 40 μm long, about 25 μm in diameter; whorled within 

nodes, covered by cortical involucres, bulging out fertile nodes. 

Sexual plants not observed.

Habitat. On rock, often mixed with other algae in 

algal turfs; intertidal.

Distribution. Gulf of California: Isla Turner, off 

SE end of Isla Tiburón (Islas de la Cintura). Eastern Pacific: Isla 

San Benedicto (Islas Revillagigedo); Guerrero; El Salvador; Costa 

Rica; Colombia. Central Pacific: Hawaiian Islands. Western Pacific: Philippines; Vietnam.

 Type Locality. Growing within tufts of Asteronema breviarticulatum (J. Agardh) Ouriques et Bouzon (2000); 

near the margin of the seaward reef opposite the Enewetak Marine Biology Laboratory, Parry Island, Enewetak Atoll (Eniwetok), Ralik Archipelago, northwest Marshall Islands.

Remarks. Ceramium vagans is not well known in 

the northern Gulf. It has been more widely reported in the tropical Pacific: Philippines (Silva et al., 1987); Enewetak (Dawson, 

1957b); Palmyra Atoll; Fiji (South and Skelton, 2000); French 

Polynesia (Payri et al., 2000); Micronesia (Lobban and Tsuda, 

2003). It is also reported in the western Atlantic from Brazil (Villaca et al., 2010).

Ceramium zacae Setchell et N. L. Gardner

Ceramium zacae Setchell et N. L. Gardner, 1937:89, pl. 8: fig. 22a–c; Dawson, 

1945c:62; 1950c:134, figs. 27, 28; 1957a:8; 1959a:30; Dawson et al., 

1960b:12, 24; Dawson, 1961b:441; 1962b:67, pl. 26: figs. 4–6; Norris 

and Hollenberg, 1970:118; Abbott and Hollenberg, 1976:598, fig. 542; 

Mendoza-González and Mateo-Cid, 1986:425; Scagel et al., 1989:165; 

Mateo-Cid et al., 1993:48; González-González et al., 1996:190; Silva 

et al., 1996b:233; Mateo-Cid et al., 2000:66; L. Aguilar-Rosas et al., 

2000:131; Hernández-Herrera et al., 2005:147; Pérez-Estrada et al., 

2012:191.

Algae epiphytic, with prostrate and erect portions, up to 6 

mm high; main axes 100–300 μm in diameter, tapering upward 

with upper branches reduced in diameter; branching subdichotomous, more densely branched toward apices, with occasional proliferous branches. Apices straight and forcipate. Corticated only 

at the nodes; internodes short throughout the thallus; lower internodes about as long as broad. Periaxial cells number 5; each cuts 

off 2 cells acropetally that overlap the periaxials. Each acropetal 

cell cuts off (1–)2 cells acropetally; these in turn, commonly cut off 

an additional cell acropetally. Periaxial cells in lower nodes cut off 

1(–2) cell obliquely basipetal. Nodes truncate on the lower side.

Reproduction not seen in our material. Tetrasporangia 

naked, emergent, 35–40 μm in diameter; whorled 3–4 at a node, 

or on either adaxial or abaxial sides of axes. Cystocarps surrounded by involucral branchlets; borne lateral in the upper portion of axes. Spermatangia in adaxial patches on the nodes in 

upper parts of axes (after Dawson, 1962b).

Habitat. Epiphytic on Gelidium and other algae and 

on red mangrove (Rhizophora mangle) prop roots; low intertidal.

Distribution. Gulf of California: Puerto Peñasco; 

Punta Cirio to Segundo Cerro Prieto, Bahía Kino; Puertecitos 

to Bahía Agua Verde; Bahía de La Paz to Punta Arena; Jalisco. 

Eastern Pacific: northern Washington; southern California to 

Punta Abreojos (inside of Bajos Wright) and Rocas Alijos, Baja 

California Sur.

Type Locality. Epiphytic on Codium fragile; Bahía 

Tortuga (southeast side of Bahía San Bartolomé), Baja California 

Sur, Pacific Mexico.

Corallophila Weber-van Bosse

FIGURE 89B

Corallophila Weber-van Bosse, 1923:339.

Algae are prostrate axes that give rise to erect axes that may 

be unbranched or with subdichotomous or adventitious branching. Axes attach to hosts or substrate by rhizoids that develop 

from periaxial and inner cortical cells. Axes composed of a central row of large axial cells that are almost completely covered 

by smaller cells of the corticating filaments, except for narrow 

gaps separating the adjacent cortical segments of successive axial 

cells. Each axial cell cuts off 4–12 periaxial cells (depending on 

species) at its distal end, and each periaxial cell cuts off four cortical initials that develop the cortical filaments [except C. itonoi 

(Ardré) R. E. Norris, 1993, which has pseudoperiaxial cells (see 

Itono, 1977a, fig. 16P]. Two acropetal initials are cut off from the 

anterior end of a periaxial cell, and two basipetal initials are cut 

off from the posterior end. Cortical growth is predominately in 

the basipetal (descending) direction; basipetal cortical filaments 

are simple or may branch, consist of three or more rectangular 

cells aligned in parallel longitudinal rows, and descend to cover 

the axial cell (internode). The two acropetal cortical filaments 

are short, ascending, and composed of two to three rounded cells 

not aligned in longitudinal rows. Cortication is mostly one cell 

layer thick; axes and branches are similarly corticated. Spines are 

present in some species.

Tetrasporangia are tetrahedrally divided, partially or completely embedded in the cortical layer (except in C. itonoi), and 

borne toward the end of erect branches or on short, stichidia-like 

branchlets (Norris, 1993). Cystocarps, currently known for only 

two of the species (Cho et al., 2000), are borne lateral on erect 

branches and usually consist of two gonimolobes, without involucres or sterile branches. Spermatangia are in superficial patches 

on ordinary cortical cells in the upper thallus.

Remarks. Although the distinctiveness of the genus 

Corallophila is controversial (e.g., Wollaston in Guiry and Guiry, 

2008–2010), some have recognized the genus (e.g., Price and 

Scott, 1992; Norris, 1993; Yoshida, 1998; Abbott, 1999). Cho 

et al. (2000:323, tbl. 1) confirmed the generic concept of Corallophila of Norris (1993).

In the Gulf of California, the cortical pattern of Corallophila is most similar to Centroceras, which also has rectangular 

cortical cells arranged in somewhat regular longitudinal rows. 

Corallophila is distinguished by two basipetal cortical initials 

that develop from the posterior end of each periaxial cell, with 
194 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

each basipetal filament branching once, whereas in Centroceras the basipetal filaments do not branch and only one basipetal cortical initial is issued per periaxial cell, with the other 

descending cortical filament developing basipetally from an 

acropetal cortical initial (see diagram comparing cortical units 

in Figure 89A, B).

One species of Corallophila occurs in the northern Gulf of 

California.

Corallophila bella (Setchell et N. L. Gardner) R. E. Norris

FIGURE 89C

Centroceras bellum Setchell et N. L. Gardner, 1924:779, pl. 26: fig. 48, 

pls. 40c, 78; Dawson, 1944a:321; 1961b:441; 1962b:69, pl. 27: fig. 

4; Hommersand, 1963:244, fig. 30b–l; González-González et al., 

1996:184. 

Corallophila bella (Setchell et N. L. Gardner) R. E. Norris, 1993:395; Abbott 

et al., 2002:306, with query.

Ceramiella bella (Setchell et N. L. Gardner) Børgesen in Díaz-Piferrer, 

1969a:202, nom. nudum.

Ceramiella bella (Setchell et N. L. Gardner) Díaz-Piferrer, 1969b:179.

Algae consist of axes arising from prostrate axes and becoming erect, 1.0–1.5 cm tall; completely corticated (except for narrow 

gaps between cortical segments); branching irregular, subsecund 

to subdichotomous; adventitious branches common; attached to 

the substrate by numerous rhizoids issued by the periaxial or inner 

cortical cells of prostrate axes. Main axes about 110–130 μm in 

diameter, gradually tapering to a single apical cell; apex slightly 

curved. Periaxial cells 8–10 at the distal end of an axial cell; each 

periaxial cell issues 2 acropetal initials that develop into short corticating filaments and 2 basipetal cortical initials. Corticating cells 

FIGURE 89. Diagrammatic illustrations comparing cortical units of the genera Centroceras and Corallophila and cortication pattern detail of Corallophila bella. A. Centroceras: A typical periaxial cell issues 

3 cortical filament initials, the first 2 from its distal end and a third from its proximal end. The first distal 

initial develops only acropetally (short filaments, spines, or gland cells), and the second distal initial grows 

both acropetally and basipetally, producing a long descending filament. The solitary proximal cortical 

initial grows only basipetally, cutting off a long descending filament. B. Corallophila: In most species a 

periaxial cell issues 4 cortical filament initials—2 distally that develop short acropetal filaments and 2 

proximally that issue basipetal filaments that are longer and branch. (Abbreviations: P, periaxial cell; ci, 

cortical initial. Basipetal (descending) filaments are stippled. A, B, drawn with modifications after R. E. 

Norris, 1993, figs. 1b, 2b.) C. Corallophila bella: Note slightly curved, undivided apices; upper portion 

of erect axis with tetrasporangia immersed within the cortex in rings around the nodes; and cortical cells 

in regular vertical rows (type specimen drawings after Setchell and Gardner, 1924, pl. 26: fig. 48).
NUMBER 96 • 195

of basipetal filaments are quadrate and arranged in straight rows 

parallel to the axis. Filament cells midway through a mature cortical segment may be longer than other corticating cells (Setchell 

and Gardner, 1924; Norris, 1993). Spines absent.

Tetrasporangia cruciately divided; immersed beneath the 

cortex; in a ring around nodes, in slightly swollen branches. Cortical cells are often smaller in tetrasporangial axes. Carpogonial 

and spermatangial thalli unknown in Gulf of California material. 

Habitat. Known from drift, cast ashore. 

Distribution. Gulf of California: Guaymas. Western Pacific: Vietnam. 

Type Locality. Cast ashore; Guaymas, Sonora, 

Gulf of California, Mexico.

Remarks. In the Gulf, Corallophila bella is most easily separated from the similar-looking Centroceras species by its 

lack of circinate apices and the absence of spines. Seemingly rare 

in the northern Gulf of California, Corallophila bella remains 

only known from the type specimen, Centroceras bellum Setchell et N. L. Gardner (1924) from Guaymas, Sonora (Dawson, 

1962b; Hommersand, 1963). It is apparently more common 

elsewhere, having been reported in the western Pacific from Vietnam (Abbott et al., 2002), the eastern Atlantic from Sierra Leone 

(Lawson and John, 1987), and the Persian Gulf and Oman Sea 

from Iran (Sohrabipour and Rabii, 1999).

Gayliella T. O. Cho, L. McIvor et S. M. Boo

Gayliella T. O. Cho, L. McIvor et S. M. Boo in Cho et al., 2008:723.

Algae epiphytic, composed of prostrate axes that give rise 

to erect axes, and attach to host by elongate unicellular rhizoids 

issued only from periaxial cells (1 per periaxial cell), with rhizoids often ending in a digitate pad. Axes are corticated only at 

the nodes and branch alternately and terminate with forcipate 

apices. Nodes consist of 4–9 periaxial cells, with each periaxial 

cell producing (2–)3–4 corticating filament initials. The single 

basipetally directed cortical initial is developed by a transverse 

(horizontal) division near the posterior end of a periaxial cell; 

this basipetal cell is horizontally elongate (about same width as 

the periaxial or pseudoperiaxial cell) and remains undivided or 

may undergo further divisions depending on species. Gland cells 

often present.

Tetrasporangia are developed only by the periaxial cells, a 

single tetrasporangium per periaxial cell, that is somewhat covered by cortical filament cells. Cystocarps are borne near apices 

and surrounded by involucral branches. Spermatangial parent 

cells are issued by cortical cells and produce spermatangia that 

cover the cortical surface. 

Four species of Gayliella are currently known in the northern Gulf of California.

KEY TO THE SPECIES OF GAYLIELLA IN THE NORTHERN GULF OF CALIFORNIA

1a. Gland cells clavate, projecting markedly from node; often greater than 40 μm long . . . . . . . . . . . . . . . . . . G. fimbriata

1b. Gland cells absent or, if present, spherical to ovoid, not projecting notably from node; smaller, less than 25 μm long . . . 2

2a. Pseudoperiaxial cells present between periaxial cells; nodal cells arranged in regular vertical columns; acropetal and 

basipetal cortical initials produced by transverse division of periaxial or pseudoperiaxial cells, width of initial nearly 

equal to that of producing cell; tetrasporangia cruciately divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. recticortica

2b. Pseudoperiaxial cells not present between periaxial cells; nodal cells not arranged in regular vertical columns; only 

basipetal cortical initial produced by transverse division of periaxial cells (initial may remain horizontally elongate or 

may divide further depending on species); tetrasporangia tetrahedrally divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Periaxial cells number 4; horizontally elongate basipetal cortical cells remain apparent in mature cortical pattern . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. species A

3b. Periaxial cells number 6–7; horizontally elongate basipetal cortical cells indiscernible in mature cortex as they continue 

to divide, resulting in numerous smaller cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. taylorii

Gayliella fimbriata (Setchell et N. L. Gardner) T. O. Cho et 

S. M. Boo

FIGURE 90

Ceramium fimbriatum Setchell et N. L. Gardner, 1924:777, pl. 26: 

figs. 43, 44; Setchell and Gardner, 1937:88, pl. 7: fig. 18; Dawson, 1944a:317; 1950c:123; 1959a:30; 1961b:440; 1962a:56, pl. 

19: fig. 3, pl. 20: figs. 6, 7; 1966a:27; Chávez-Barrear, 1972b:269; 

Itono, 1977a:33, 106, 197, figs. 13I, 14E–G, 37D; Huerta-Múzquiz, 

1978:338; Pedroche and González-González, 1981:66; HuertaMúzquiz and Mendoza-González, 1985:52; Mendoza-González 

and Mateo-Cid, 1986:425; Sánchez-Rodríguez et al., 1989:44; 

Mendoza-González and Mateo-Cid, 1992:20; Abbott, 1999:272, 

fig. 76A–C; González-González et al., 1996:186; CONANP, 

2002:138; Pacheco-Ruíz and Zertuche-González, 2002:468; 

Pacheco-Ruíz et al., 2008:211. 

Gayliella fimbriata (Setchell et N. L. Gardner) T. O. Cho et S. M. Boo in Cho 

et al., 2008:723, fig. 2a–q; H.-S. Kim, 2012:95: figs. 73–74; Jeong et al, 

2013:443, fig. 3.

Algae minute; composed of prostrate axes giving rise to 

erect axes, up to 8 mm tall, 80–150 μm wide basally; attached 

to the substratum by unicellular rhizoids issued from periaxial 

cells. Branching regularly alternate, at intervals of 3–5 axial 

cells in main axes and intervals of 4–6 axial cells in lateral axes; 

with forked, slightly incurved apices. Axes corticated only at the 

nodes, internodes short in upper portions, lengthening markedly 

in basal and prostrate portions. Axial cells are spherical near 

apices and elongate to cylindrical below. Periaxial cells number 

6–7, each periaxial cell divides off 3 cortical filament initials. The 

first 2 cortical initials cut off obliquely from the anterior end of 

the periaxial cell and develop 2 acropetal corticating filaments, 
196 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

and the third initial, cut off transversely (horizontally) from the 

posterior end of the periaxial cell, is horizontally elongate and 

later continues to divide. The acropetal corticating filaments 

are 3–4 cells long, and the basipetal filament is 2–3 cells long. 

Where a lateral branch occurs, 1 periaxial cell produces an additional cortical initial that develops an extra acropetal cortical 

filament. Protruding stout, bulbous, clavate gland cells, issued 

from the cortical cells (initially by terminal cells of acropetal filaments), are at first abaxially arranged and later whorled about 

the nodes (later may develop on basipetal cortical filament cells 

also). Gland cells up to 40(–60) μm long and upwardly directed.

Tetrasporangia spherical, 55–65 μm in diameter; whorled 

at nodes and partially covered by cortical filaments (Dawson, 

1962a). Gametophytes not known in the Gulf.

Habitat. Epiphytic on Padina and other algae, sometimes entangled with other algae; intertidal to shallow subtidal 

(also dredged from 40 m depths; Dawson, 1962a:57).

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena; Mazatlán, Sinaloa to Jalisco. Eastern Pacific: 

Punta Banda, Baja California to Punta Eugenia (“San Eugenio”), 

Baja California Sur; Guerrero. Central Pacific: Hawaiian Islands. 

Western Pacific: Japan; Korea. 

Type Locality. Floating; Eureka, near La Paz, Baja 

California Sur, Gulf of California, Mexico.

Remarks. The large, protruding, clavate gland cells 

of G. fimbriata distinguish it from other Gayliella species. Won 

and Cho (2010) reported differences in their molecular phylogenetic analysis between Gulf of California type locality G. fimbriata and those of Korea; however their data are not yet published 

(H.-S. Kim, 2012).

Gayliella species A

FIGURE 91

Ceramium gracillimum var. byssoideum sensu Dawson, 1957c:21; 1959a:30; 

1961b:440; 1962a:57, pl. 20: figs. 2, 3, pl. 21: figs. 2, 3; Abbott and 

Hollenberg, 1976:597, fig. 538; Huerta-Múzquiz, 1978:338; Schnetter 

and Bula-Meyer, 1982:152, pl. 25: figs. L–O, pl. 27: fig. C; MendozaGonzález and Mateo-Cid, 1986:425; Pacheco-Ruíz and ZertucheGonzález, 2002:468 [non Ceramium gracillimum var. byssoideum

(Harvey) Feldmann-Mazoyer, 1938:323; 1940:293, fig. 109].

FIGURE 90. Gayliella fimbriata: A. Habit of erect axes, with series of protruding gland cells on abaxial side. B. Mature cortical pattern with 

clavate gland cells, some whorled about node (A, B, JN-5062, US Alg. Coll. microscope slide 5263). 
NUMBER 96 • 197

Thalli forming epiphytic minute tufts, up to 10 mm high, with 

prostrate and erect axes, up to 80–100 μm in diameter basally; attached by rhizoids from prostrate or lower portions of erect axes. 

Rhizoids unicellular, developed only from periaxial cells, with 

blunt tips or with digitate attachment discs. Apices forcipate and 

slightly incurved. Branching alternately at intervals of 4–6 axial 

cells in main axes and intervals of 6–10 axial cells in lateral axes. 

Nodes in midportions up to 65 μm wide and to 45 μm tall (long). 

Internodes long in prostrate and basal portions of the axes. Four 

periaxial cells encircle a node, periaxial cells somewhat triangular 

FIGURE 91. Gayliella species A: A. Mature cortical pattern at nodes 

(JN-4406, US Alg. Coll. microscope slide 5233). B. Cortication pattern 

at nodes (JN-4834, US Alg. Coll. microscope slide 5250). C. Tetrasporangia. D. Unicellular rhizoid issued by periaxial cell, terminating with 

a digitate attachment pad (C, D, JN-4139, US Alg. Coll. microscope 

slide 5225). 
198 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

in shape. Each periaxial cell cuts off 3 cortical initials: 2 from the 

anterior end of the periaxial cell are cut off obliquely and develop 

acropetal cortical filaments; 1 cut off transversely from the posterior end is horizontally elongate and may divide transversely again 

to form a second horizontally elongate cell and infrequently may 

undergo 1 further transverse division. Each of the acropetal corticating filaments is 2–3 cells long, each basipetal filament is 2–3 

cells long. Gland cells occasionally present, ovoid, up to 15 μm in 

diameter, most often at ends of acropetal cortical filaments.

Tetrasporangia 30–45 μm in diameter, borne singly at a 

node (Figure 91C) or whorled (Dawson, 1950c, as Ceramium 

masonii), each partially covered by cortical filament cells (“involucres”). Female thalli not found in Gulf material. Spermatangial 

superficial, covering cortical surface cells (Dawson, 1962a).

Habitat. Epiphytic on other algae; intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena.

Remarks. Our northern Gulf specimens (US Alg. Coll.) 

referred to Gayliella species A are in agreement with those that 

Dawson (1962a) identified as “Ceramium gracillimum var. byssoideum,” which are now recognized to belong in the genus Gayliella. 

They somewhat resemble small Gayliella mazoyerae T. O. Cho, 

Fredericq et Hommersand (in Cho et al., 2008) and G. transversalis (F. S. Collins et Hervey) T. O. Cho et Fredericq (in Cho et al., 

2008), but Gayliella species A differs in that its mature basipetal 

filaments are 2(–3) horizontally elongate cells long, whereas those 

of both G. mazoyerae and G. transversalis have only 1 basipetal 

horizontally elongate cell. In other species of Gayliella slight differences in nodal cortication have been shown to be consistent with 

differences in molecular sequence data (Cho et al., 2008). It seems 

best to await DNA sequence data on the Gulf specimens to establish species limits before we describe Gayliella species A as a new 

species solely on the differences in the cortical pattern we observed. 

It is also similar to Ceramium dawsonii A. B. Joly (1957:150, pl. 

19: figs. 1a–d) from Brazil, but Cho et al. (2008) found that genetically three different species had been referred to “Ceramium 

dawsonii.” Although all three belong in the genus Gayliella, the 

generic status of C. dawsonii was left unresolved until its type can 

be examined and compared to their Brazilian specimens.

Gulf of California specimens identified as “Ceramium flaccidum (Harvey ex Kützing) Ardissone (1871)” from Puerto Peñasco (Mateo-Cid et al., 2006), Santa Teresa, and Puertecitos 

(L. Aguilar-Rosas et al., 2000), Bahía de Los Ángeles (PachecoRuíz et al., 2008), Bahía de La Paz (Pérez-Estrada et al., 2012), 

and Mazátlan (Mendoza-González et al., 1994) should be reexamined to verify its presence in the Gulf or they may belong 

here. Ceramium masonii E. Y. Dawson (1950c), considered to be 

a synonym of “C. gracillimum var. byssoideum” sensu Dawson 

(1954b, 1962a), also needs to be reexamined so its taxonomic 

status and relationship to Gayiella species A can be resolved.

Gayliella recticortica (E. Y. Dawson) T. O. Cho et S. M. Boo

FIGURE 92

Ceramium recticorticum E. Y. Dawson, 1950c:124, pl. 3: figs. 23, 24; 

1961b:441; 1962a:63, pl. 24: figs. 5, 6; González-González et al., 

1996:188; Cho et al., 2002b:277–289, figs.1–43; Pacheco-Ruíz and 

Zertuche-González, 2002:468; Pacheco-Ruíz et al., 2008:211.

Gayliella recticortica (E. Y. Dawson) T. O. Cho et S. M. Boo in Cho et al., 

2008:736.

Thalli minute tufts, to 3(–5) mm tall; main axes 45–75 μm in 

diameter, of a uniseriate row of axial cells corticated only at the 

nodes, with long internodes basally; attached to host by elongate 

unicellular rhizoids produced by periaxial cells of prostrate and 

basal portions of erect axes; a periaxial cell produces only 1 rhizoid. Apices forcipate and slightly incurved; branching alternate, 

at intervals of 4–5 segments along main axes and intervals of 5–7 

segments in lateral branches. Four periaxial cells encircle a node, 

along with 4–5 pseudoperiaxial cells, each cut off laterally on the 

adaxial side of a periaxial cell, except for the first formed periaxial cell that issues a pseudoperiaxial cell laterally on two sides. 

Periaxial and pseudoperiaxial cells divide transversely from both 

anterior and posterior ends to produce rectangular, horizontally 

elongate acropetal and basipetal corticating cells, which may divide transversely again during further development. First formed 

periaxial cell produces 3 vertical columns of cells (1 from itself 

and 1 from each of its 2 pseudoperiaxial cells); the other periaxial cells produce 2 vertical rows (1 from themselves and 1 file 

of cells from their pseudoperiaxial cell). Cortical pattern of 4–5 

columns (vertical rows) visible in lateral view appears orderly 

as somewhat rectangular periaxial, pseudoperiaxial, and cortical 

cells of the basipetal filaments and acropetal cortical initials are 

FIGURE 92. Gayliella recticortica: Cortication pattern at nodes 

(EYD-501-46, paratype, AHFH, now UC).
NUMBER 96 • 199

of similar width. Ultimate cells of the acropetal filaments smaller 

and less rectangular. Gland cells spherical to ovoid, small, 9–12 

μm in diameter, originate from terminal cells of both acropetal 

and basipetal corticating filaments (Cho et al., 2002b).

Reproductive structures produced in the upper portions of 

the thallus. Tetrasporangia cruciately divided, 20–45 μm in diameter, within a hyaline envelope; whorled at the nodes, 1 to 

4 tetrasporangia (1 per periaxial cell), covered by cortical cells. 

Cystocarps spherical; composed of up to 3 gonimolobes and surrounded by 2–4 involucral branchlets. Spermatangia minute, 

colorless spheres, develop on spermatangial parent cells borne 

on cortical cells; start on adaxial side and later covering entire 

cortical surface of a node (Cho et al., 2002b).

Habitat. Epiphytic on Gastroclonium and on various other algal hosts; low intertidal to shallow subtidal.

Distribution. Gulf of California: Bahía Bocochibampo, Sonora; Puerto Balandra (east side of Bahía de La Paz) 

and Punta Perico, Baja California Sur; Mazatlán, Sinaloa. Eastern Pacific: Galápagos Islands.

Type Locality. Epiphytic on Gastroclonium pacificum; Bahía Bocochibampo, near Guaymas, Sonora, Gulf of 

California, Mexico.

Remarks. Gayliella recticortica has been reported 

from the Great Barrier Reef (Price and Scott, 1992:107, as Ceramium recticorticum). However, the Australian “G. recticortica” may not be the same as the Gulf of California Gayliella 

recticortica. Although both have acropetal and basipetal cortical 

initials that are horizontally elongate and cortical cells arranged 

in regular longitudinal rows, nodes of Australian “G. recticortica” (see Price and Scott, 1992: fig. 34A, B) are more simple and 

regular, with all of the nodal cells somewhat equal in width. Also, 

in the Mexican material including the Gulf of California type of 

G. recticortica (Cho et al., 2002b, as Ceramium recticorticum), 

the acropetal corticating filaments divide, with two little cells and 

gland cells often present (distal margin more irregular than photo 

of Australian alga). In the Australian “G. recticortica,” pseudoperiaxial cells are apparently absent, so there are fewer longitudinal rows in its cortical band (Price and Scott, 1992:108, fig. 

34A–B) than are found in the Gulf of California specimens and 

the type of G. recticortica (Cho et al., 2002b: figs. 2–4, 11–19).

Gayliella taylorii (E. Y. Dawson) T. O. Cho et S. M. Boo

FIGURE 93

Ceramium taylorii E. Y. Dawson, 1950c:127, pl. 2: fig. 13, pl. 4: figs. 31–33; 

1954a:6; 1957c:21; 1959a:30; 1961b:441; 1962a:65, pl. 26: figs. 1–3; 

1966a:27; Itono, 1972:76, fig. 1B; Abbott and Hollenberg, 1976:598, 

fig. 541; Itono, 1977a:108, 198, figs. 13J, 14H; Huerta-Múzquiz, 

1978:335; Pedroche and González-González, 1981:66; HuertaMúzquiz and Mendoza-González, 1985:52; Mendoza-González and 

Mateo-Cid, 1992:20; González-González et al., 1996:189; FernándezGarcía et al., 2011:61.

Gayliella taylorii (E. Y. Dawson) T. O. Cho et S. M. Boo in Cho et al., 

2008:727, fig. 4a–l.

Thalli of prostrate and erect axes, to 7–12 mm high and 

to 120 μm in diameter, alternately branched with forcipate 

and incurved apices. Main axes with 3–4 axial cells between 

branching points, and in lateral branches 4–6 axial cells between branches. Unicellular rhizoids issued from periaxial cells 

in prostrate axes and in the basal portion of erect axes. Axes 

corticated only at the nodes; axial cells cut off 6–7 periaxial cells 

at their distal end. Each periaxial cell produces 3 cortical initials that develop corticating filaments: first 2 cortical initials, cut 

off obliquely from the anterior end of a periaxial cell, form the 

acropetal filaments; remaining initial, cut off transversely from 

the posterior end of the periaxial cell, forms a horizontally elongated basipetal cell that undergoes further divisions, developing 

the basipetal filament. Each acropetal corticating filament 3–4 

cells long; basipetal filament 2–3 cells long. Horizontally elongate nature of basipetal cells in mature cortical nodes diminishes 

as continued divisions break the cell up into smaller angular 

cells. Small ovoid gland cells, to 12 μm in diameter, develop from 

acropetal cortical filament cells.

Tetrasporangia whorled at a node, about 30 μm in diameter, covered by acropetal cortical filament cells. Cystocarps 

surrounded by 5–6 involucral branches; develop near apices. 

Spermatangia as for genus.

Habitat. Epiphytic on Prionitis, Chaetomorpha, and 

probably other algae, also on rocks; intertidal.

Distribution. Gulf of California: Puerto Peñasco; 

Isla Patos (off north end of Isla Tiburón); Isla Partida; Isla Rasa 

(Isla Raza); Guaymas, Sonora; La Paz to Cabeza Ballena; Mazatlán, Sinaloa to Jalisco. Eastern Pacific: southern California to 

Bahía Magdalena, Baja California Sur; Isla San Benedicto (Islas 

Revillagigedo); Guerrero; Oaxaca; El Salvador; Costa Rica. 

Western Pacific: China.

Type Locality. Cabeza Ballena, Baja California 

Sur, Gulf of California, Mexico.

Ceramiaceae tribus Pterothamnieae

Ceramiaceae tribus Pterothamnieae Athanasiadis, 1996a:44.

One genus of the tribe Pterothamnieae is represented in the 

northern Gulf of California.

Pterothamnion Nägeli in Nägeli et Cramer

Pterothamnion Nägeli in Nägeli et Cramer, 1855:66.

Platythamnion J. Agardh, 1892:22.

Algae are erect, richly branched uniseriate filaments, usually 

with sinusoidal apices, that are attached to substratum or host by 

multicellular rhizoids issued from the basal region of axes. Thalli 

are composed of axes of unlimited growth with whorl branches 

of determinate growth, whorl branches generally of 2 dissimilar pairs. Axial filament cells bear 2 to 4(–5) whorl branches; 

2 major subequal or unequal lateral whorl branches opposite 

each other and may additionally bear 1–2 (rarely 3) transverse 

minor whorl branches opposite each other. Longer (major) 

whorl branches may be simple or branched up to 4 orders and 

are commonly in distichous patterns, tristichous to tetrastichous, 

and abaxial and/or adaxial or with adaxial pairs of branchlets. 
200 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

The minor transverse whorl branch pairs may be dimorphic, distinctly shorter, with a different branching pattern, or just less developed and nearly as long as the major pair of whorl branches. 

Terminal spines are common in certain species. Indeterminate 

lateral branches arise in place of long (major) whorl branches 

in a regular, alternate sequence in the plane of the frond, at intervals of 2–8(–15) cells or irregularly from axial filament cells 

(Wollaston, 1968:303; Athanasiadis and Kraft, 1994). Adventitious new axes can also develop from the basal cells (and less 

commonly from other cells) of whorl branches. Axes are usually 

ecorticated but may be loosely to densely corticated by descending rhizoids in lowermost portions of axes. Gland cells may be 

common to rare (seldom absent), variable in size and shape, usually sessile, and borne adaxially on an intercalary cell of whorl 

branches and branchlets.

Mature tetrasporangia are subspherical and cruciately to 

decussately divided, sessile or pedicellate, and borne singly or in 

groups, on cells of whorl branches or proximal branchlet cells. 

Gametophytes usually dioecious, procarps develop near apices 

of indeterminate axes, carpogonial branches are borne singly, or 

several in a series, on basal cell of consecutive (and/or opposite) 

whorl branches that act as support cells. Carposporangia are 

in several rounded groups (gonimolobes), subtended by whorl 

branches from the axial cells below. In most species there is usually 

only 1 carposporophyte per indeterminate axis. Spermatangia are 

in whorls, terminal on short spermatangial structures that replace 

various orders of branchlets or branch cells (after Athanasiadis 

and Kraft, 1994; Athanasiadis, 1996a; Womersley, 1998).

Three species of Pterothamnion are known in the northern 

Gulf of California.

KEY TO THE SPECIES OF PTEROTHAMNION IN THE NORTHERN GULF OF CALIFORNIA

1a. Major whorl branches (longer pair) with 3–4 branchlets from each cell (tristichous or tetrastichous), or at least the more 

proximal cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. orbignianum

FIGURE 93. Paratypes of Gayliella taylorii: A and B. Mature cortication pattern at nodes (A, EYD-1962; A, US Alg. Coll. microscope slide 441; 

B, EYD-1961, US Alg. Coll. microscope slide 440).
NUMBER 96 • 201

1b. Major whorl branches with 1 or 2(–3) branchlets from most cells, or at least the more proximal cells . . . . . . . . . . . . . 2

2a. Major whorl branches pectinate, branchlets borne nearly exclusively on upper side (adaxial) of whorl branch cells, rarely 

an abaxial branchlet on periaxial cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. pectinatum

2b. Major whorl branches distichous and pinnate, branchlets borne on upper and lower sides of proximal whorl branch 

cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. tepocensis

Pterothamnion orbignianum (Montagne) Nägeli

FIGURE 94

Callithamnion orbignianum Montagne, 1837:351; 1839:7, pl. 7: fig. 4; Kützing, 1861:27, pl. 84: fig. 2.

Pterothamnion orbignianum (Montagne) Nägeli, 1862:376; Athanasiadis, 

1996a:51, figs. 9D, 11.

Antithamnion orbignianum (Montagne) De Toni, 1903:1403; Dawson et 

al., 1964:76, pl. 71: fig. C, pl. 73: figs. A–C; Ramírez and Santelices, 

1991:308.

Platythamnion orbignianum (Montagne) J. Agardh, 1892:23; Howe, 

1914:154; Taylor, 1947:82.

Platythamnion heteromorphum f. reversum Setchell et N. L. Gardner, 

1903:345, pl. 25.

Platythamnion reversum (Setchell et N. L. Gardner) Kylin, 1925:54, fig. 

34d–f; Dawson, 1961b:439; 1962a:8, pl. 1: fig. 4d–f; Wollaston, 

1972b:48, figs. 1, 7b, 10; Scagel et al., 1989:226; González-González 

et al., 1996:249.

Pterothamnion reversum (Setchell et N. L. Gardner) Athanasiadis et Kraft, 

1994:130.

Algae are up to 2 cm long or more; axes ecorticate, branching to 

a greater extent basally; at intervals of 4–5 axial cells in distichousalternate pattern; axial cells up to 600 μm long and to 300 μm 

in diameter in basal portions; becoming shorter in upper portions. 

Axial cells with 4 whorl branches of 2 different kinds: a pair of opposite major (long) branches and a pair of opposite minor (short) 

branches. Major whorl branches up to 650 μm long, and tetrastichously branched, i.e., with 4 branchlets of 2 kinds from each cell 

(or at least the more basal ones) similar to primary main axes. Each 

long whorl branchlet of a major whorl-branch with branchlets to 

either side (usually pectinate with most branches on the adaxial side 

in relation to branchlet axis) and transverse branchlets shorter and 

simpler, both types tapering to acute tips. Transverse minor whorl 

branches composed of a subspherical basal cell bearing a group of 

short, branched spinose branchlets that may be simple (a basal cell 

and a spine) or with 3 pronged spines from a basal cell; in some the 

spinose branchlets occasionally lacking. Gland cells occasional on 

cells of whorl branches and branchlets.

Tetrasporangia subspherical, cruciately divided, to 35 μm 

long, on 1-celled pedicels (mostly unbranched) replacing ultimate 

branchlets. Female gametophytes not known in Gulf of California. Spermatangial clusters with spermatia borne terminally on 

short branchlets, occurring in place of ultimate branchlets on 

major (long) whorl branches (after Wollaston, 1972b).

Habitat. Epiphytic or entangled in larger algae; shallow subtidal, down to 40 m depths.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda; Isla San Esteban (Islas de la Cintura). 

Eastern Pacific: British Columbia to Oregon; Peru.

Type Locality. [Puerto] Callao, Constitutional 

Province of Callao, Peru.

Pterothamnion pectinatum (Kylin) Athanasiadis et Kraft

FIGURE 95

Platythamnion pectinatum Kylin, 1925:53, figs. 32D, 33E, 34A–C; Smith, 

1944:316, pl. 79: fig. 1; Dawson, 1961b:439; 1962a:6, pl. 1: fig. 4a–c, 

pl. 4: figs. 2, 3; 1966b:64; Wollaston, 1972b:51; 1976:588, fig. 528; 

Norris and Bucher, 1976:18; Stewart and Stewart, 1984:145; Scagel et 

al., 1989:226; González-González et al., 1996:249.

Pterothamnion pectinatum (Kylin) Athanasiadis et Kraft, 1994:130; Athanasiadis, 1996a:61; Spalding et al., 2003:277; Serviere-Zaragoza et al., 

2007:11; Pacheco-Ruíz et al., 2008:211.

FIGURE 94. Pterothamnion orbignianum: Portion of axis showing 

heteromorphic opposite pairs of whorl branches, bearing tetrasporangia and gland cells (from Kylin, 1925: fig. 34f).
202 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 95. Pterothamnion pectinatum: A. Branching habit (JN-5512, US Alg. Coll. microscope slide 4706). B. Upper portion of an axis focused on plane to show minor whorl branches bearing gland cells (JN-5263, US Alg. Coll. microscope slide 4711). C. Tetrasporangia borne in 

branchlets of whorl branches (JN-5512, US Alg. Coll. microscope slide 4706). D. Each axial cell with dissimilar opposite pairs of whorl branches 

(JN-5263, US Alg. Coll. microscope slide 4710).
NUMBER 96 • 203

Platythamnion pectinatum var. laxum W. R. Taylor, 1945:266; Dawson, 

1945c:57; 1961b:439; González-González et al., 1996:249.

Thalli up to 1.5(–3.5) cm high, with sinusoidal apices, axes 

up to120(–225) μm in diameter, axes completely uncorticated. 

Axial cells generally 1.0–1.7(–2.5) times as long as wide. Axial 

cells bearing 4 whorl branches, 2 pairs of two different types. 

Mature major whorl branches 6–8(–10) cells long, 250–430 

μm in length, in basal portions of thallus; pectinately branched, 

with a series of branchlets on the adaxial side; sometimes with 

a pair of branchlets on periaxial cells and rarely the adjacent 

cell. Branchlets also pectinately branched, but abaxially as related to the rachis of the whorl branch. Branches and branchlets 

gradually diminish in diameter with each branch order, tapering 

to acute terminal cells. Pair of minor transverse whorl branches 

simple in young parts; when mature, transverse whorl branches 

composed of a basal cell with several 1–3(–7) upwardly directed 

independent short unbranched or branched branchlets; each up 

to 6 cells long, mostly up to 75 μm in length (can be longer, up 

to 180 μm, when on an axial cell that bears an indeterminate 

lateral branch). Gland cells 12–30 μm and abundantly scattered 

over the thallus, borne laterally on cells of both major and minor 

whorl branches, occasionally in a series.

Tetrasporangia cruciately divided, to 27–30(–45) μm long, 

and borne successively and usually abundantly on cells of proximal pectinate branchlets. Spermatangia terminal in clusters on 

short branchlets borne on cells of whorl branches (usually adaxial). Carposporangia in several rounded groups (3 gonimolobes), 

subtended by stout whorl branches from axial cells below, typically, 1 carposporophyte develops per indeterminate lateral.

Habitat. On hard substrata or epiphytic on other 

algae; low intertidal to shallow subtidal down to 25 m depths.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda to Isla Las Ánimas (Isla San Lorenzo 

del Norte); Bahía de San Lucas. Eastern Pacific: Alaska to Isla 

Guadalupe, Baja California; Isla Clarión (Islas Revillagigedo).

Lectotype Locality. On piles at docks; Friday 

Harbor, San Juan Island, San Juan County, Washington (Athanasiadis, 1996a).

Remarks. Pterothamnion pectinatum appears to be 

the most common species of Pterothamnion in the northern Gulf 

of California.

Pterothamnion tepocense (E. Y. Dawson) Athanasiadis et Kraft

Platythamnion tepocense E. Y. Dawson, 1944a:314, pl. 72: fig. 1 (as P. 

tepocensis); 1961b:439; 1962a:7, pl. 2; González-González et al., 

1996:249.

Pterothamnion tepocense (E. Y. Dawson) Athanasiadis et Kraft, 1994:130; 

Athanasiadis, 1996a:53.

Algae up to 3 cm tall; of sparsely branched, main axes of 

large cells, (50–)70–105 μm long and 50–70 μm in diameter in 

upper portions, 150–225 μm long and 150 μm (or more) in diameter in lower portions. Axial cells with 4 whorl branches each; 

an opposite pair of compound longer lateral whorl branches and 

another pair of simpler minor whorl branches borne transversely. 

Most major whorl-branches to 500 μm long, curving and tapering upward; bearing opposite pinnate secondary branchlets, 

(30–)60–100 μm long, occasionally with third order of branchlets, tips acute. Gland cells frequent; borne on a single cell of 

whorl-branches or branchlets.

Tetrasporophyte and carposporophytes unknown. Spermatangia in clusters mostly on proximal cells of major 

whorl-branches.

Habitat. Subtidal; known only from type collection 

dredged in 22 m depth.

Distribution. Gulf of California: Bahía Tepoca 

(southeast side of Cabo Tepoca; Hast Heeque Coopol in the language of the Seri).

Type Locality. Bahía Tepoca, Sonora, Gulf of California, Mexico.

Remarks. Pterothamnion tepocense is known only 

from the northern Gulf type (Dawson, 1944a, as Platythamnion 

tepocensis) and possibly another specimen dredged from 38 m 

depth, Bahía Sebastián Vizcaíno (Pacific Baja California Sur) that 

was tentatively referred to this species (Dawson, 1962a).

Dasyaceae

Dasyaceae Kützing, 1843:413, 414.

Thalli are erect or partially prostrate and erect, composed 

of terete to compressed, branched polysiphonous axes that are 

ecorticate or corticated by compact descending rhizoid-like filaments. The major axes are polysiphonous, with 4–13 pericentral 

cells, and have determinate pseudolaterals that are either monosiphonous or monosiphonous only distally with proximal segments polysiphonous; the pseudolaterals may be free or united 

into a network. The leading axis is sympodial early in development, and branching may be radially or bilaterally or sometimes 

dorsiventrally organized.

Life histories are triphasic, where known, with isomorphic 

gametophytes and tetrasporophytes. Ultimate branches of the 

monosiphonous pseudolaterals are modified to become regenerated axes (polysiphonous with 4–5 pericentral cells) and the pericentral cells develop the reproductive structures. Procarps may 

also be formed on sympodial developed axes. Tetrasporangia are 

tetrahedrally divided, each with two to four cover cells, in cylindrical or compressed stichidia borne on the ultimate branches 

of the pseudolaterals, with several (4–6) tetrasporangia on each 

segment of a stichidium. Gametophytes are usually dioecious. 

Each procarp has a four-celled carpogonial branch and two 

groups of sterile cells. The fertilized carpogonium cuts off one or 

two connecting cells, one of which fuses with the auxiliary cell. 

A fusion cell and usually an ostiolate pericarp are formed after 

fertilization. Spermatangial stichidia cylindrical or lanceolate; 

spermatangial parent cells are divided off from pericentral cells 

of a modified ultimate branch of a pseudolateral; spermatangia 

form a dense colorless layer around it.

There are two genera, each in a different subfamily of the 

Dasyaceae, represented in the northern Gulf of California.
204 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

KEY TO THE GENERA OF DASYACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Pseudolaterals monosiphonous; pseudolaterals usually from every axial segment; usually radially (spirally) arranged; 

axial segments with (4–)5 pericentral cells; most northern Gulf species corticated . . . . . . . . . . . . . . . . . . . . . . . . Dasya

1b. Pseudolaterals monosiphonous distally, polysiphonous in proximal portions (at least basalmost segment); pseudolaterals 

not borne from every axial segment; usually bilaterally (distichously) branched; axial segments with 4–12 pericentral 

cells; northern Gulf species uncorticated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Heterosiphonia

Dasyaceae subfam. Dasyoideae

Dasyaceae subfam. Dasyoideae F. Schmitz et Falkenberg, 1897:471; H.-G. 

Choi et al., 2002:564.

The subfamily Dasyoideae is currently represented by one of 

its nine genera in the northern Gulf of California.

Dasya C. Agardh

Dasya C. Agardh, 1824:xxxiv, 211.

Algae are erect or partially prostrate, with sympodial apices, with main axes and branches terete and polysiphonous, 

with (4–)5 pericentral cells around the central axial filament 

cell, and often corticated by rhizoid-like filaments. Axes bear on 

every polysiphonous segment, radially placed pigmented, usually subdichotomously branched monosiphonous pseudolaterals 

of limited growth and sometimes adventitious monosiphonous 

filaments present. Cells are cut off by the pericentral cells that 

form corticating filaments that grow downward over lower pericentral cells. Monosiphonous filaments are sometimes corticated 

at their base or polysiphonous (this character not seen in species 

from the northern Gulf).

Tetrasporangia are tetrahedrally divided, with 2–4 cover cells, 

and borne in stichidia on pseudolaterals. Gametophytes are usually 

dioecious. Female reproductive structures are developed on polysiphonous segments of axes. The carposporophyte is surrounded by 

a well-developed pericarp, often with prominent elongated neck 

and ostiole. Spermatangial stichidia may be conical, subcylindrical, to linear-lanceolate, often with several sterile cells or filament 

at their tip; spermatangia are grouped in successive whorls that 

form colorless sheaths about branches of pseudolaterals.

There are five taxa including three species, one with two 

varieties and another with a subspecies and two varieties, in the 

northern Gulf of California.

KEY TO THE SPECIES, SUBSPECIES, AND VARIETIES OF DASYA IN THE NORTHERN GULF OF CALIFORNIA

1a. Terminal cells of pseudolaterals acute . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. spinigera

1b. Terminal cells of pseudolaterals blunt, rounded . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 

2a. Pseudolaterals narrow near their base, 15–40 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2b. Pseudolaterals wider near their base, 40–110 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3a. Pseudolaterals sparse, axes nearly barren in lower portions; pseudolaterals short, mostly less than 500(–960) μm long

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. pedicellata subsp. stanfordiana var. nudicaulis

3b. Axes densely clothed with pseudolaterals; pseudolaterals longer, mostly 1–7 mm long . . . . . . . . . . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. pedicellata subsp. stanfordiana var. stanfordiana

4a. Pseudolaterals narrower, mostly 60–85 μm in diameter, tending to be deciduous, leaving much of the axis bare . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. sinicola var. sinicola

4b. Pseudolaterals generally wider near their base, 80–110 μm in diameter, tending to persist, more densely covering upper 

branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D. sinicola var. californica

Dasya pedicellata subsp. stanfordiana (Farlow) J. N. Norris et 

Bucher comb. nov.

FIGURE 96

Dasya stanfordiana Farlow, 1902:94; Setchell and Gardner, 1930:164; Taylor, 1945:287, pl. 97: fig. 2; Dawson, 1961b:448; Serviere-Zaragoza et 

al., 1993a:483. 

Dasya baillouviana var. stanfordiana (Farlow) J. N. Norris et Bucher, 

1976:19; Norris, 1985d:210; González-González et al., 1996:197; 

Cruz-Ayala et al., 2001:191; Pacheco-Ruíz and Zertuche-González, 

2002:468; Mateo-Cid et al., 2006:57; Pacheco-Ruíz et al., 2008:211.

Dasya pedicellata var. stanfordiana (Farlow) E. Y. Dawson, 1963b:407, pl. 

128: fig. 3, pl. 130; 1966a:28; Huerta-Múzquiz, 1978:338; Stewart 

and Stewart, 1984:146; Huerta-Múzquiz and Mendoza-González, 

1985:52; Serviere-Zaragoza et al., 1993a:483; González-González et 

al., 1996:197; CONANP, 2002:138.

Dasya pedicellata sensu Dawson, 1944a:324; 1949c:237; 1951:56; 1957a:8; 

1961b:448; Silva et al., 1996b:233 [non Dasya pedicellata (C. Agardh) 

C. Agardh, 1824:211].

Thalli erect, up to 25 cm tall, from a small discoid holdfast, axes polysiphonous, with 5 pericentral cells; completely but 

thinly corticated below the first 7–8 apical segments; sparingly 

to freely alternately branched, lateral branches infrequently redivided. Branches mostly 0.4–2.0 mm in diameter, densely covered 

with monosiphonous, repeated dichotomously branched pseudolaterals or sometimes lacking monosiphonous pseudolaterals 

in lower portions. Pseudolaterals 1–7 mm long and 15–40 μm 
NUMBER 96 • 205

FIGURE 96. Dasya pedicellata subsp. stanfordiana: A. Cystocarpic thallus (JN-4731, US Alg. Coll.-159017). B. Habit of a tall, delicate specimen (JN-4724, US Alg. Coll.-159015). C. Corticated axis bearing slender long pseudolaterals. D. Spermatangial stichidium (JN-5165, US Alg. 

Coll. microscope slide 4852). E. Old nearly empty tetrasporangial stichidium showing cover cells and two tetrasporangia, with a terminal, sterile 

apical filament (C, E, JN-4724, US Alg. Coll. microscope slide 4855). 
206 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

in diameter near their base, attenuated upward to 7–12 μm in 

diameter at their tips.

Tetrasporangial stichidia lanceolate to linear-lanceolate, 80–

140 μm in diameter and to 800 μm long; tetrasporangia 40–50 

μm in diameter. Cystocarps, 200–370 μm in diameter, usually 

borne laterally on slightly elongate ultimate branchlets, arising 

from indeterminate axes, apparently pedicellate when arising 

near end of a short lateral branch, urceolate, with narrow ostiolate neck. Spermatangial stichidia lanceolate to linear-lanceolate, 

250–560 μm long, 60–90 μm in diameter, usually filament tipped.

Habitat. On rocks, or occasionally epiphytic; mid 

intertidal to subtidal, 5.0–22 m depths.

Distribution. Gulf of California: Playa Hermosa (vicinity of Puerto Peñasco) to Guaymas, Sonora; Puerto 

Refugio, Isla Ángel de la Guarda to Bahía Agua Dulce, Isla Tiburón; Caleta Santa María (north of Puerto Santa Rosalía) to 

La Paz, Baja California Sur; Topolobampo; Sinaloa to Nayarit; 

Isla María Magdalena, Islas Marías (Islas Tres Marías). Eastern 

Pacific: Bahía San Quintín to Punta Abreojos, Baja California; 

Isla Guadalupe; Rocas Alijos (about 299 km [186 miles] west of 

Cabo San Lázaro, Baja California Sur); Galápagos Islands.

Syntype Localities. Two localities in the Galápagos Islands, Ecuador, were listed for Dasya stanfordiana by 

Farlow (1902:94): Isla Wolf (Isla Wainman, usually misspelled 

“Wenman”) and Punta Tortuga, Isla Isabela (Albemarle Island).

Remarks. Dasya pedicellata (C. Agardh) C. Agardh 

(1824; basionym: Sphaerococcus pedicellatus C. Agardh, 1822; 

type locality: New York, USA) is herein recognized as distinct 

species following others (e.g., Guiry and Guiry, 2010). Some 

have followed Montagne (1841) in considering D. pedicellata

to be conspecific with D. baillouviana (S. G. Gmelin) Montagne 

(1841; basionym: Fucus baillouviana S. G. Gmelin, 1768; lectotype illustration Griselini, 1750: pl. 2, in Dixon and Irvine, 

1970:480, fig. 2). Pena-Martín et al. (2007) also treated them 

as a single species and proposed to conserve a new type for 

Fucus baillouviana, but that was rejected by the “Nomenclature 

Committee for Algae” (Prud’homme van Reine, 2011; who also 

suggested the Mediterranean “D. baillouviana” may belong to 

different cryptic species then that of New York).

Dawson (1963b:408) recognized similarities between the 

Pacific Dasya stanfordiana Farlow (1902) and the western Atlantic D. pedicellata but considered differences in the position of 

the cystocarps as a character to support their taxonomic separation. Cystocarps are borne laterally on “somewhat elongate ultimate branchlets” of D. stanfordiana versus the terminal position 

on very short ultimate branchlets of D. pedicellata. Considering 

the similarities of the Gulf of California specimens to the Atlantic 

D. pedicellata and noting the differences pointed out by Dawson 

(1963b) and their apparent geographical isolation, at this time 

we propose to recognize them as a subspecies, Dasya pedicellata subsp. stanfordiana. Further comparative morphological 

and molecular testing of the Gulf of California specimens, with 

types and topotype materials of the eastern Pacific D. stanfordiana (syntype localities: Galápagos Islands), northwestern Atlantic D. pedicellata (lectotype locality: New York; Silva et al., 

1996a), and D. baillouviana (S. G. Gmelin) Montagne (1841; 

type locality: Mediterranean Sea; Silva et al., 1996a; Lipkin 

and Silva, 2002) will help elucidate their taxonomic status and 

relationships.

Specimens of “D. cf. pedicellata” tentatively reported from 

Isla Monserrate in the southern Gulf by Dawson (1959a:42) 

need to be reexamined. Studies of the natural product chemistries of northern Gulf of California D. pedicellata subsp. stanfordiana revealed interesting secondary products, simple phenols 

of aromatic structure, that were shown to have antibiotic activity 

(Fenical and McConnell, 1976).

Dasya pedicellata subsp. stanfordiana var. nudicaulis

(E. Y. Dawson) J. N. Norris et Bucher, comb. nov.

FIGURE 97

Dasya pedicellata var. nudicaulis E. Y. Dawson, 1963b:406, pl. 128: fig. 1, pl. 

131: fig. 6; González-González et al., 1996:197.

Dasya baillouviana var. nudicaulis (E. Y. Dawson) J. N. Norris et Bucher, 

1976:19; González-González et al., 1996:197; Pacheco-Ruíz and 

Zertuche-González, 2002:468.

Algae erect, up to 50 cm long or more, lower branched axes 

3–4 mm in diameter; branching alternately to irregularly subdichotomously; holdfasts not observed. Dasya pedicellata subsp. 

stanfordiana var. nudicaulis differs from D. pedicellata subsp. 

stanfordiana var. stanfordiana in having heavily corticated, 

nearly barren axes and branches, with sparse, shorter pseudolaterals, mostly less than 500(–960) μm long.

Habitat. On rocks; subtidal, 15–22 m depths.

Distribution. Gulf of California: Roca Blanca, 

Puerto Refugio, Isla Ángel de la Guarda; Bahía de Los Ángeles; 

Puerto Escondido.

Type Locality. Bahía de Los Ángeles, Baja California, Gulf of California, Mexico.

Remarks. On the basis of the large size (to 50 cm—

and probably longer, as only portions of noncomplete thalli have 

been collected) and marked lack of pseudolaterals of Dasya pedicellata subsp. stanfordiana var. nudicaulis, Dawson (1963b, as 

D. pedicellata var. nudicaulis) suggested that its habit represents 

a modification by its deepwater habitat. Our Puerto Refugio 

FIGURE 97. (Opposite) Dasya pedicellata subsp. stanfordiana var. nudicaulis: Habit, showing mostly barren axes below, and an increasing 

number of pseudolaterals in upper thallus (JN-5800, US Alg. Coll.-159009).
NUMBER 96 • 207
208 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

specimens collected by scuba at depths of 15–22 m (Norris 

and Bucher, 1976) were of similar habit but with much longer 

branches; some were more than 50 cm in length, with wide axes, 

3–4 mm in diameter (JN-5800, US Alg. Coll.-159009).

Dasya sinicola (Setchell et N. L. Gardner) E. Y. Dawson var. 

sinicola

FIGURES 98D, 99B,C

Heterosiphonia sinicola Setchell et N. L. Gardner, 1924:770, pl. 28: figs. 59, 

60, pl. 47b.

Dasya sinicola (Setchell et N. L. Gardner) E. Y. Dawson, 1959a:32, fig. 

3B; 1961b:448; 1963b:408, pl. 128: fig. 4, pl. 158: fig. 3; 1966a:29; 

Norris, 1973:16; Abbott and Hollenberg, 1976:675, fig. 622; HuertaMúzquiz, 1978:338; Stewart and Stewart, 1984:146; Huerta-Múzquiz 

and Mendoza-González, 1985:52; Sánchez-Rodríguez et al., 1989:45; 

Mateo-Cid et al., 1993:49; Mendoza-González et al., 1994:108; 

González-González et al., 1996:197; Mateo-Cid et al., 2000:67; L. 

Aguilar-Rosas et al., 2000:131; CONANP, 2002:138; L. Aguilar-Rosas 

et al., 2002:235; Riosmena-Rodríguez et al., 2005a:33; Mateo-Cid et 

al., 2006:57; Pacheco-Ruíz et al., 2008:211; Castañeda-Fernández de 

Lara et al., 2010:199.

Algae erect, 3–10 cm tall; of terete axes abundantly 

branched. Axes with 5 pericentral cells, heavily corticated (except at the tips). Monosiphonous pseudolaterals dichotomously 

branched, 2–4 orders. Axes more densely covered with tufts of 

monosiphonous pseudolaterals near apices. Determinate pseudolaterals, 0.6–1.5 mm long and (50–)60–80(–100) μm in diameter near base, upward becoming attenuated, with subacute 

to blunt tips; tending to be deciduous, often leaving much of the 

axis bare.

Tetrasporangial stichidia conical to cylindrical, 200–400 μm 

long; 1 to several borne off pseudolaterals or adventitious monosiphonous laterals. Cystocarps borne on the main axes, urceolate, 450–500 μm wide by 600 μm tall, with prominent beaked 

rostrum. Spermatangial stichidia short, mostly on lower fork of 

a pseudolateral, and usually with 1–3 sterile terminal cells.

Habitat. On rocks or epiphytic on other algae; low 

intertidal to shallow subtidal, down to 7 m depths.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara); Bahía La Choya (Bahía Cholla), Puerto 

Peñasco to Cabo San Lucas; Mazátlan, Sinaloa. Eastern Pacific: 

Santa Catalina Island (California Channel Islands); Isla Guadalupe to Bahía Magdalena, Baja California Sur.

Type Locality. La Paz, Baja California Sur, Gulf of 

California, Mexico.

Remarks. In addition to Dasya sinicola var. sinicola

there are two other taxonomic varieties reported in the Gulf of 

California: Dasya sinicola var. californica (see description herein) 

and D. sinicola var. abyssicola (E. Y. Dawson) E. Y. Dawson 

(1963b) from the southern Gulf and Pacific Mexico from Islas 

Revillagigedo (Huerta-Múzquiz and Garza-Barrientos, 1975; 

Serviere-Zaragoza et al., 2007) and Oaxaca (Mateo-Cid and 

Mendoza-González, 1997).

Dasya sinicola var. californica (N. L. Gardner) E. Y. Dawson

FIGURES 98A, 99A

Dasya californica N. L. Gardner, 1927c:340, pl. 66: fig. 2; Dawson, 1951:53; 

1952:431; 1954c:344; 1961b:448; González-González et al., 1996:197.

Dasya sinicola var. californica (N. L. Gardner) E. Y. Dawson, 1963b:409, pl. 

127: fig. 2, pl. 128: fig. 2, pl. 158: figs. 1, 2; Abbott and Hollenberg, 

1976:676, fig. 624; Stewart and Stewart, 1984:146; Mendoza-González 

and Mateo-Cid, 1985:28; Sánchez-Rodríguez et al., 1989:43; Stewart, 1991:151; Mateo-Cid et al., 1993:49; Mateo-Cid and MendozaGonzález, 1994b:41; González-González et al., 1996:198.

Dasya eastwoodiae Setchell et N. L. Gardner, 1930:165; Dawson, 1961b:448; 

Stewart and Stewart, 1984:148; González-González et al., 1996:197.

Dasya sinicola var. californica shares similar-sized axes 

(400–1000 μm in diameter) with D. sinicola var. sinicola. It is 

generally not as tall but is usually coarser, with stiffer, wider incurved pseudolaterals (80–110 μm in diameter near their base) 

FIGURE 98. Diagrammatic comparisons of determinate monosiphonous pseudolaterals of Dasya species: A. Dasya sinicola var. 

californica, a coarse pseudolateral of comparatively wider cells. B, C. 

Dasya spinigera: B. Close-up showing acute terminal cell of a pseudolateral branch. C. Single pseudolateral (redrawn from type). D. 

Dasya sinicola var. sinicola, a thin pseudolateral (A–D, after Dawson, 1963a: pl. 128: figs. 2, 4–6). 
NUMBER 96 • 209

that tend to persist and thus more densely cover the branches, 

whereas the determinate pseudolaterals of D. sinicola var. sinicola are generally more lax, (60–80 μm in diameter near their 

base) and frequently deciduous.

Habitat. On rocks; low intertidal.

Type Locality. La Jolla, San Diego County, California, USA.

Distribution. Gulf of California: Playa Hermosa, 

Puerto Peñasco to Bahía Concepción. Eastern Pacific: Santa 

Catalina Island (California Channel Islands); Newport Bay and 

La Jolla (southern California); Isla Guadalupe; Punta María to 

Punta Malarrimo, Baja California; Bahía Tortugas (inside southeast Bahía San Bartolomé) to Todos Santos, Baja California Sur.

Remarks. Dasya sinicola var. californica is larger and 

usually has coarser pseudolaterals (80–110 μm in diameter at base) 

that generally persist, making the upper branches more densely 

covered than the other varieties, D. sinicola var. sinicola and 

D sinicola var. abyssicola. Described from the California Channel Islands, D. sinicola var. abyssicola (Dawson, 1963b; Dawson 

and Neushul, 1966) is apparently a subtidal species. It has been 

reported in the southern Gulf from 8 to 16 m depths, Punta Los 

Frailes, Baja California Sur (Dawson, 1963b). Dasya sinicola var. 

abyssicola can be distinguished primarily in being much smaller, 

only 10–13 mm tall, with axes 200–300 μm in diameter and pseudolaterals measuring 40–50 μm in diameter at their bases.

Dasya spinigera E. Y. Dawson

FIGURE 98B,C

Dasya spinigera E. Y. Dawson, 1963b:410, pl. 128: figs. 4, 5, pl. 158: fig. 

4; Schnetter and Bula-Meyer, 1982:170, pl. 32: figs. B–D; GonzálezGonzález et al., 1996:198.

Algae 2.5–5 cm tall; of terete axes, 250–350 μm in diameter 

in lower to middle portions; sparsely branched at 2–10 mm intervals; main axis and branches similar, both covered with persistent, branched pseudolaterals, 400–500 μm long; attached by a 

small discoid holdfast (only partly seen in type specimens). Axis 

of 5 pericentral cells; partly corticated with short developing filaments produced from pericentral cells in younger portions, fully 

corticated in older portions. Determinate pseudolaterals, rigid, 

divaricate-dichotomously branched 4–5 times, with segments of 

1–2 cells, 25–30 μm in diameter, and cells 50–60 μm in length, 

terminal cells sharply pointed.

FIGURE 99. Varieties of Dasya sinicola. A. Dasya sinicola var. californica: Habit (JN-3696, US Alg. Coll.-159037). B, C. Dasya sinicola var. 

sinicola: B. Rhizoidally corticated polysiphonous axes with “straight” dichotomously branched pseudolaterals. C. Sessile broad-based cystocarp 

with ostiolate pericarp with distinct neck (B, C, EYD-26119, US Alg. Coll. microscope slide 792).
210 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Reproductive structures not known.

Habitat. On shell fragments in sand bottom; subtidal, dredged from 20–22 m depths.

Distribution. Gulf of California: Bahía Tepoca; 

Bahía de San Lucas. Eastern Pacific: Isla Gorgona, Colombia.

Type Locality. Sand bottom, dredged from 20 m 

depth; Bahía de San Lucas, Baja California Sur, Gulf of California, Mexico.

Remarks. A seemingly rare species, Dasya spinigera

is only known from the two original Gulf of California collections (Dawson, 1963b) and a collection reported from Isla Gorgona, Pacific Colombia (Schnetter and Bula-Meyer, 1982).

Dasyaceae subfam. Heterosiphonioideae

Dasyaceae subfam. Heterosiphonioideae H.-G. Choi, Kraft, I. K. Lee et 

G. W. Saunders, 2002:564.

The subfamily Heterosiphonioideae is represented by one of 

its seven known genera in the northern Gulf of California.

Heterosiphonia Montagne

Heterosiphonia Montagne, 1842d:4, nom. cons.

Algae are chiefly erect or decumbent, arising from prostrate 

axes or discoid holdfasts. Axes are terete to slightly compressed 

and either with or without rhizoidal cortication. They are 

branched alternately or subdichotomously and are distichously 

to subdistichously arranged or dorsiventrally organized. Thalli 

are polysiphonous, with 4 or 7–13 pericentral cells per segment. 

Determinate pseudolaterals are subdichotomously or alternately 

branched and distally monosiphonous and may be polysiphonous in proximal portions. Pseudolaterals or lateral branches 

arising 2–9 polysiphonous segments apart.

Tetrasporangia are tetrahedrally divided and in stichidia 

that occur as branches of pseudolaterals or on special monosiphonous or polysiphonous stalks. There are 4–6(–9) tetrasporangia 

whorled on each segment of the stichidium. Each sporangium is 

covered by 4 cover cells at maturity. Gametophytes are dioecious. 

The carpogonial branch is 4-celled with 2 groups of sterile cells. 

Cystocarps are conspicuous, ovoid to urn shaped, and generally 

develop near the bases of pseudolaterals near the apices of indeterminate axes. In some, the female reproductive structures may 

be formed on monosiphonous filaments. The cystocarps contain 

a fusion cell and well-developed corticated pericarp with ostiole. 

Spermatangial stichidia occur as branches of the pseudolaterals. 

Spermatangia are in successive whorled series that surround an 

ultimate–subultimate filament to form an elongate stichidia that 

is occasionally tipped by several sterile cells. 

There are two taxa, one species and a variety of another species, known in the northern Gulf of California.

KEY TO THE SPECIES OF HETEROSIPHONIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Axes 280–400 μm in diameter; determinate pseudolaterals polysiphonous in proximal portions, distally monosiphonous; 

tetrasporangial stichidia borne on polysiphonous base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. erecta

1b. Axes 80–185(–200) μm in diameter; determinate pseudolaterals with basal polysiphonous segment 1(–2) cells in length, 

thereafter monosiphonous; tetrasporangial stichidia with monosiphonous base . . . . . . . . . . . . . . H. crispella var. laxa

Heterosiphonia crispella var. laxa (Børgesen) M. J. Wynne

FIGURE 100

Heterosiphonia wurdemannii (Bailey ex Harvey) Falkenberg var. laxa

Børgesen, 1919:327, figs. 327, 328; Dawson, 1957c:22; 1959a:32; 

1961b:448; 1963b:404, pl. 129: fig. 1; Schnetter and Bula-Meyer, 

1982:171, pl. 32: fig. A; Stewart and Stewart, 1984:146; MendozaGonzález et al., 1994:109; González-González et al., 1996:225. 

Heterosiphonia crispella (C. Agardh) Wynne var. laxa (Børgesen) M. J. 

Wynne, 1985c:87; Mateo-Cid et al., 2000:67; Mateo-Cid et al., 

2006:57; Bernecker, 2009:CD-Rom p. 65; Fernández-García et al., 

2011:62.

Algae decumbent, plumose, composed of uncorticated axes 

and branches; up to 2 cm long and 80–185(–200) μm in diameter; creeping, entangled branched axes attached to host or 

substratum by rhizoids or modified tips at the ends of pseudolaterals (40–60 μm in diameter). Primary axes and indeterminate 

laterals polysiphonous, with 4 pericentral cells; determinate 

pseudolaterals monosiphonous except for single (rarely 2) polysiphonous basal segment(s), (55–)60–95(–110) μm in diameter. 

Determinate pseudolaterals, subdistichously arranged along 

the axes; developed alternately, mostly on every second axial 

segment; subdichotomously branched 3–5 times, up to 1.4 mm 

long; gradually attenuated upward, to 15–25 μm diameter at 

blunt tips. One filament at the first dichotomy of the determinate pseudolaterals often remains unbranched or may sometimes grow downward and is modified to attach to substratum; 

the other filament of the first dichotomy branches subdichotomously 3–4 times.

Tetrasporangial stichidia, somewhat conical, up to 250 

μm in length, 75 μm in diameter; terminal on monosiphonous 

ultimate branchlets (on a 1–4-cell-long pedicel); tetrasporangia about 20 μm in diameter, overlaid by cover cells (Dawson, 

1963a). Cystocarps not seen. Spermatangia develop as outer surface layer on a portion of ultimate branchlets of pseudolaterals, 

forming cylindrical to lanceolate stichidia.

Habitat. Epiphytic or entangled on larger algae, including Dictyota, Padina, and Dictyopteris; intertidal to shallow 

subtidal, down to 3.5 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to Puerto Libertad; narrow channel between the northwestern 

end of Isla Espíritu Santo and southern end of Isla Partida Sur; 

Punta Arena (north of Cabo Pulmo) to Bahía de San Lucas; 
NUMBER 96 • 211

FIGURE 100. Heterosiphonia crispella var. laxa: A. Upper portion of alga showing determinate pseudolaterals, each composed of a branched 

group of incurved branches and a conspicuous abaxial uniseriate unbranched member (JN-4898, US Alg. Coll. Microscope slide 4889). B. Polysiphonous axis bearing on every other segment a determinate pseudolateral, monosiphonous except for a polysiphonous basal segment (JN4898, US Alg. Coll. microscope slide 4889). C. Tetrasporangial stichidium terminal on a pseudolateral (note this is an unusual mixed-phase 

specimen with spermatangia on surface; JN-4155, US Alg. Coll. microscope slide 4883). D. Developing spermatangial stichidium (JN-4898, 

US Alg. Coll. microscope slide 4889). E. Detail of mixed-phase tetrasporangial stichidium with spermatangia on cover cells (JN-4155, US Alg. 

Coll. microscope slide 4884). 
212 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Mazátlan. Eastern Pacific: Isla Guadalupe; Costa Rica; Colombia; Galápagos Islands.

Type Locality. St. Croix, U.S. Virgin Islands, Caribbean Sea.

Remarks. In the northern Gulf, we only found specimens in agreement with H. crispella var. laxa sensu Dawson 

(1963b:405, as “H. wurdemannii var. laxa (J. Bailey ex Harvey) 

Falkenberg, in Schmitz and Falkenberg, 1897”) and none that 

could be identified as H. crispella var. crispella (cf. Børgesen, 

1919; Taylor, 1960, as “H. wurdemannii var. wurdemannii”; basionym: Callithamnion crispellum C. Agardh, 1828).

Dawson (1963b, as H. wurdemannii var. laxa) suggested this 

distinctive variety “is actually a separate species” from the Atlantic H. wurdemannii, reflecting the comments of Falkenberg (in 

Schmitz and Falkenberg, 1897, Falkenberg, 1901). The taxonomic 

status of Gulf of California H. crispella var. laxa and its relationship to those from the Caribbean type locality need to be tested.

An unusual mixed-phase specimen of H. crispella var. laxa

bearing spermatangia on the tetrasporangial stichidia was discovered from San José del Cabo (JN-4155, US Alg. Coll. microscope slides 4883 and 4884; Figure 100C, E) in the southern 

Gulf. The reproductive structures with both tetrasporangia and 

spermatangia were similar in shape to tetrasporangial stichidia. 

Mixed-phase thalli have been reported in various other ceramialean algae (e.g., H.-G. Choi and Lee, 1996; Y. K. Lee et al., 1995).

Heterosiphonia erecta N. L. Gardner

FIGURE 101

Heterosiphonia erecta N. L. Gardner, 1927f:99, pl. 20: figs. 1, 2, pl. 21; 

Setchell and Gardner, 1937:84, pl. 21: figs. 42, 43, pl. 22: fig. 44, 

pl. 23: fig. 46; Taylor, 1945:288; Dawson, 1949b:26, pl. 7: fig. 43; 

1951:53; 1957a:8; 1961b:448; 1963b:403, pl. 127: figs. 3, 4; Dawson and Neushul, 1966:182; Abbott and Hollenberg, 1976:676, fig. 

625; Stewart and Stewart, 1984:146; Mendoza-González and MateoCid, 1985:30; Sánchez-Rodríguez et al., 1989:45; Stewart, 1991:152; 

González-González et al., 1996:225; Silva et al., 1996b:233; CONANP, 

2002:138; Pacheco-Ruíz and Zertuche-González, 2002:468; PachecoRuíz et al., 2008:212; Castañeda-Fernández de Lara et al., 2010:199.

Algae erect or partly prostrate, up to 5 cm long; uncorticated throughout; polysiphonous main axes and branches with 

segments of 4 pericentral cells, 280–400 μm in diameter, attached to host by rhizoids. Growth sympodial. Pseudolaterals 

of limited growth alternate, from every second (to fourth) axial 

segment, distichously arranged; basally polysiphonous, similar 

to main axes but ending in monosiphonous ultimate branchlets, 

8–12 cells in length, with acute apices.

Tetrasporangial stichidia cylindrical with conical apex, 

borne on polysiphonous base; tetrasporangia tetrahedrally divided. Cystocarps sessile, flask shaped, 600–700 μm in diameter 

at base, with long neck and ostiole; usually infrequent, near base 

of ultimate branchlets. Spermatangia dense, colorless clusters of 

small cells forming sheaths surrounding the lower part of ultimate monosiphonous branchlets, beginning 1–3 cells from the 

base (Dawson, 1949b: pl. 7: fig. 43).

Habitat. Epiphytic on or entangled with various 

algae or sea grasses; low intertidal to shallow subtidal, down to 

10 m depths.

Distribution. Gulf of California: Isla Coronado (Isla 

Smith) to Islas de Los Gemelos, Bahía de Los Ángeles; Bahía de 

Loreto. Eastern Pacific: Santa Catalina Island and Anacapa Island 

(California Channel Islands) to La Jolla, California; Islas Todos 

Santos and Isla Guadalupe (Baja California) to Isla Magdalena, 

Bahía Magdalena and Rocas Alijos (Baja California Sur); Ecuador.

Type Locality. Epiphytic on the sea grass, Phyllospadix; La Jolla, San Diego County, southern California, USA.

Delesseriaceae

Delesseriaceae Bory de Saint-Vincent, 1828:181.

Algae membranous, compressed to flat, many foliose, often 

with midribs and macroscopic or microscopic veins, a few genera 

small parasites. Thalli undivided, lobed, or much branched from 

midrib, blade margins, or surface or in a few genera forming a 

perforated blade or lattice-work. Blades monostromatic to polystromatic, attached by discoid, rhizoidal, and/or stoloniferous 

holdfasts. Algae initially uniaxial, but some genera later losing 

strictly apical growth, and growth appears to be from marginal 

meristems with intercalary cell divisions (diffuse growth) that 

constructs pseudoparenchymatous sheets, 1 or more cells thick. 

In some members, growth from apical cells continues through 

maturity, and in some of these an axial filament forms and issues 2 lateral pericentral cells to each side as well as 2 transverse 

pericentral cells that lie on top and beneath the axial filament 

cell, forming a polystromatic midrib. The lateral pericentral cells 

developing cell rows to several orders that form the blades; cells 

may be united laterally by secondary pit connections.

Tetrasporangia subspherical and tetrahedrally divided, aggregated in sori on blade or near margins of blade, some with 

sori in special leaflets or proliferations. Gametophytes dioecious. 

Carpogonial branches (3–)4-celled, bearing 1 or 2 groups of sterile branches composed of 1 to several cells. In some members, 

carpogonial branches develop from transverse pericentral cells 

along midline near apices; in others, carpogonial branches are 

scattered over the blades (developing from blade cells). The carposporophyte develops from the diploidized auxiliary cell, usually forming a basal fusion cell, branched gonimoblast filaments 

with carposporangia terminal, single or in chains. Carposporophytes surrounded by a pericarp with an ostiole. Spermatangia 

develop in patches or sori on the blade surface or near blade 

margins or on superficial proliferations.

Remarks. Major subfamily separations are primarily based on (1) location of procarps, whether they are scattered 

over the surface of blades or restricted to primary cell rows 

(along midline), (2) presence or absence of midribs with rhizoidal cortication, and (3) presence or absence of intercalary cell 

divisions in primary cell rows (Lin et al., 2001). The ontogenetic 

development (i.e., patterns of development of cell rows in blade 

construction) and branching patterns are also valuable. Tribes 
NUMBER 96 • 213

FIGURE 101. Heterosiphonia erecta: A. Habit (JN-4746, US Alg. Coll.-160012). B. Acute cells at the tips of pseudolaterals (JN-4750, US Alg. 

Coll. microscope slide 4879). C. Short determinate pseudolaterals alternately and distichously arranged along polysiphonous axis (JN-4417, US 

Alg. Coll. microscope slide 4885). D. Polysiphonous axis bearing pseudolaterals that are proximally polysiphonous and distally monosiphonous 

(JN-4417, US Alg. Coll. microscope slide 4886). 
214 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

recognized within the family have been treated by Wynne (2001, 

2014) and Lin et al. (2012).

Thirteen genera of the Delesseriaceae are known to occur in 

the northern Gulf of California.

KEY TO GENERA OF DELESSERIACEAE AND SARCOMENIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli narrow, up to 7 cells wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Thalli more than 7 cells wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 

2a. Thallus composed of 2 different portions: terete axes (axial filament cells each surrounded by 4 pericentral cells); and 

distal flattened, determinate blades (mainly 5 cells wide) usually with free monosiphonous multicellular hairs at their 

apices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Taenioma

2b. Thallus composed of flat, narrow blades of similar structure throughout, branching from midribs; blades usually 7 cells 

wide; free monosiphonous hairs absent from blade apices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Platysiphonia

3a. Growth of blades from a primary apical cell; cell rows regularly arranged more or less “symmetrically” on each side of 

midrib; procarps/cystocarps restricted to primary cell row (midline) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3b. Growth of blades from marginal initials, or if from primary apical cell, cell rows not obviously symmetrical, irregular in 

arrangement; procarps/cystocarps scattered over blade . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 

4a. Branches arising from midrib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4b. Branches not arising from midrib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5a. Thalli rarely branched in Gulf species; not all third-order cell row initials reach blade margins, with intercalary divisions 

occurring in second-order and higher cell rows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Apoglossum

5b. Thalli occasionally to frequently branching; Gulf species with all second- and third-order cell row initials reaching blade 

margins, without intercalary cell divisions (some may have corticated midribs) . . . . . . . . . . . . . . . . . . . . . Hypoglossum

6a. Thalli subdichotomously branched; living in brackish water to freshwater (mangroves, estuaries, lagoons); tetrasporangia 

in a single layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Caloglossa

6b. Thalli not subdichotomously branched; living in marine waters; tetrasporangia in 2 or more cell layers . . . . . . . . . . . . 7

7a. Thallus branching from the margins in 1 plane; second-order cell rows of parent blade become first-order cell row (midrib) of lateral branches; all third-order cell row initials reach the thallus margin . . . . . . . . . . . . . . . . . Branchioglossum

7b. Thallus often simple (unbranched) or sometimes irregularly branched or proliferous at base; not all third-order cell row 

initials reach the thallus margin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Grinnellia

 8a. Blade with an inconspicuous or a distinct midrib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

8b. Blade without a midrib, but micro- to macroscopic veins may be present . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

9a. Monostromatic, except for micro- and macroscopic veins running irregularly and longitudinally; growth from apical 

cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Polyneurella

9b. Monostromatic to polystromatic; midrib and veins usually absent or rarely present; growth from marginal meristems and 

intercalary cell divisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Myriogramme (in part)

10a. Midrib conspicuous; mature thallus with rounded apices; apical cells becoming indistinguishable from marginal row 

initials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

10b. Midrib inconspicuous (visible with hand lens or microscope); mature thallus apices abruptly tapering to single apical 

cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

11a. Blades with irregular margins; tetrasporangia in series of longitudinal sori parallel to blade margin . . . . . Erythroglossum

11b. Blades with smooth margins; tetrasporangia in median sori near blade tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sorella

12a. Thallus monostromatic; midrib and veins usually absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Myriogramme (in part)

12b. Thallus monostromatic, with polystromatic midrib and veins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

13a. Small blades, usually 3 cm or less high, with subdichotomously branched midribs (macroscopic veins) . . . . Schizoseris

13b. Larger foliose blades, mostly more than 3 cm high; central midrib with opposite, alternate or irregularly, branched lateral 

veins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Phycodrys

Apoglossum J. Agardh

Apoglossum J. Agardh, 1898:190.

Thalli are erect or decumbent, flat, membranous blades that 

may be simple to abundantly branched. Blades are monostromatic except for the percurrent midrib, may be with or without 

lateral microscopic veins, and are attached by a small discoid 

holdfast or stoloniferous basal portion. Growth is by a transversely dividing apical cell at the tip of each blade, along with 

intercalary divisions occurring in second- and higher-order cell 

rows. In intercalary cell divisions, the new cell is cut off distally 

only (so fourth-order cell rows are always on the adaxial side of 

third-order cell rows). Third- and fourth-order cell rows are often 

short. All second-order cell rows reach the thallus margin, not all 
NUMBER 96 • 215

of the initials from the tertiary row (or fourth or higher order) 

reach the blade margin. The midrib has lateral pericentral cells 

that do not undergo transverse divisions, leaving a median strip 

three cells across of long cells; however, this may be obscured 

in species with corticated midribs. Cortication is of small-celled 

descending “rhizoidal” filaments. Branching is rare to common 

depending on the species. In those that branch, branching is endogenous, with new blades arising from the midline.

Tetrasporangia are in linear sori lying parallel along both 

sides of blade midrib, formed on the lateral pericentral cells and 

second-order row cells; or circular to oval sori toward distal 

end of blade. Gametophytes are dioecious. Procarps are on the 

midline of fertile blades, carpogonial branches with two sterile 

groups, each composed of a single cell. Cystocarps are often only 

one per blade, but sometimes there may be more. Carposporangia are borne in branched terminal chains; pericarp 3–5 cells 

thick. Spermatangia are in superficial patches (sori) between the 

second- and third-order cell rows.

One species of Apoglossum occurs in the northern Gulf of 

California.

Apoglossum gregarium (E. Y. Dawson) M. J. Wynne

FIGURE 102

Hypoglossum gregarium E. Y. Dawson, 1966b:65, fig. 6C [type specimen]; 

González-González et al., 1996:228.

Apoglossum gregarium (E. Y. Dawson) M. J. Wynne, 1985a:169, figs. 1–6; 

Ballantine and Wynne, 1985:463, figs. 9–15; Stewart, 1991:139; 

González-González et al., 1996:175; Abbott, 1999:330, fig. 95A,B; 

Wynne, 2014:48.

Phrix gregarium (E. Y. Dawson) J. G. Stewart, 1974a:147, figs. 1–11; 

González-González et al., 1996:247.

Membranoptera spatulata E. Y. Dawson, 1950b:157, fig. 15; 1961b:445; 

1962a:79, fig. 5; Wynne, 1985a:167, figs. 3–6 (holotype); Ballantine 

and Wynne, 1985:463, fig. 16 [type specimen]; González-González et 

al., 1996:243.

Algae of small, erect, delicate, membranous blades, single 

or in clumps; up to 6 mm tall, 1.0–2.5 mm wide; usually simple, 

more or less flattened or undulating; usually unbranched (or 

rarely branched from midline); oblanceolate to spatulate, with 

blunt apices. Blades monostromatic with prominent polystromatic midrib (of long, undivided lateral pericentral cells); on 

short, simple or branched stipe, with rhizomatous cortication on 

stipe, often also on basal region of midrib; attached below by a 

spreading basal disc or sometimes from cylindrical prostrate axis 

or decumbent blades in contact with substratum. Growth from 

transversely dividing apical cells; lateral cell rows initiated by the 

pericentral cells become obscured by frequent intercalary divisions (resulting irregularly shaped small cells make tracing the 

cell rows and their degree of branching difficult); not all tertiary 

cell row initials reach the blade margins.

Tetrasporangia irregularly tetrahedrally divided, up to 35 μm in 

diameter, with a surrounding hyaline envelope. Tetrasporangial sori 

long, paired, lining sides of blade midline, lateral pericentral cells 

and second-order row cells involved in tetrasporangial formation. 

Cystocarps (as reported in southern California): borne on the 

midline 1 to several per blade; prominent, protruding with large 

flared ostiole; carposporangia single, terminal on gonimoblast filaments. Spermatangial sori often numerous, forming small patches 

separated by sterile cells of second- and third-order cell rows (see 

Wynne, 1985a:167, figs. 5, 6, as Membranoptera spatulata).

Distribution. Gulf of California: Isla Patos (off N 

end of Isla Tiburón) and Isla Las Ánimas. Eastern Pacific: southern California to Baja California; Islas San Benitos (east of Isla 

FIGURE 102. Apoglossum gregarium: A. Habit, frequently 

branched from stipe and midrib with additional blades arising from 

spreading base (after Dawson, 1966b: fig. 6C, as Hypoglossum 

gregarium). B. Apical region showing apical organization; note that 

lateral pericentral cells are not transversely divided. C. Tetrasporangial sori along both sides of midrib (A–C, EYD-26123, US Alg. Coll. 

microscope slide 791; type specimen of Hypoglossum gregarium).
216 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Cedros); Galápagos Islands. Central Pacific: Hawaiian Islands. 

Western Pacific: Korea.

Type Locality. Isla Las Ánimas (Isla San Lorenzo 

del Norte), Islas de San Lorenzo, Islas de la Cintura, Gulf of 

California, Mexico.

Remarks. Wynne (1985a), in examining type material of two Gulf of California species, Hypoglossum gregarium

and Membranoptera spatulata, concluded they were conspecific, 

representing a single taxon, Apoglossum gregarium.

Although A. gregarium is sparse where found and known 

only from two islands in the northern Gulf, it has been widely 

reported elsewhere: in the western Atlantic from Puerto Rico 

(Ballantine and Wynne, 1985) and Bermuda (Schneider, 2000), 

in the Mediterranean Sea (Sartoni and Boddi, 1993), and from 

South Africa (Wynne and Norris, 1991).

Branchioglossum Kylin

Branchioglossum Kylin, 1924:8.

Algae are membranous, symmetrical blades that may be entirely erect or with erect and prostrate portions. Blades can be 

simple or branched to several orders, entire or lobed, and are 

monostromatic apart from the percurrent polystromatic midrib 

(three cells thick), which may become corticated in some species. 

The branching is primarily developed from the margins of parent blades by conversion of a second-order cell row initial into a 

first-order initial that forms the midrib of the new blade. A few 

species are also known to produce endogenous branches from 

the midrib, although less frequently than marginal branches. 

Sometimes branches from the midrib may develop associated 

with wound regeneration from the cortical cells and not endogenously (Wynne and Norris, 1991; Millar and Wynne, 1992). 

Growth is from prominent apical cells. All or some cells of the 

second-order rows bear third-order rows, and all second-order 

and third-order cell row initials reach the blade margins. There 

are no intercalary cell divisions within cell rows.

Tetrasporangia are tetrahedrally divided, developing within 

two or more cell layers in longitudinal bands of sori that run 

parallel to the midrib of the blade. Carpogonial branches, with 

two groups of sterile cells, are borne along the blade midrib, issued from pericentral cells. Spermatangial parent cells develop 

from blade surface cortical cells. Spermatangial sori are arranged 

diagonally to the blade midrib, initially in discrete patches that 

later become confluent.

Two species of Branchioglossum are known in the northern 

Gulf of California.

FIGURE 103. (Opposite) Branchioglossum bipinnatifidum: A. Habit of tetrasporangial thallus (JN-5036, US Alg. Coll.-217354). B. Blade apex 

showing apical organization, lateral blades issued from blade margins, the second-order cell rows of parent blade becoming first-order cell rows 

(midribs) of branches, and rhizoids developing from cells at blade margins (JN-5036, US Alg. Coll. microscope slide 4615). C. Tetrasporangia 

in sori to both sides of midrib (JN-4309, US Alg. Coll. microscope slide 4619). D. Spermatangial sori in patches becoming confluent (JN-3987,

US Alg. Coll. microscope slide 4625).

KEY TO THE SPECIES OF BRANCHIOGLOSSUM IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli composed of narrow linear blades, 2(–3) mm wide, habit small to relatively large (–4 cm tall); branched irregularly 

pinnate-suboppositely, 2–3 or more orders; margins not undulate . . . . . . . . . . . . . . . . . . . . . . . . . . . B. bipinnatifidum

1b. Thalli of nonlinear blades, habit relatively small (–2 cm tall), but broader, up to 5 mm in width; upper portion of several 

broad lobes, with undulate or slightly ruffled margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B. undulatum

Branchioglossum bipinnatifidum (Montagne) M. J. Wynne

FIGURE 103

Delesseria bipinnatifida Montagne, 1837:355; Montagne, 1846b:31, pl. 

6: fig. 1; Howe, 1914:138; Mikami, 1979:35, fig. 1 [type specimen]; 

Wynne, 2014:20, fig. 5a (holotype).

Branchioglossum bipinnatifidum (Montagne) M. J. Wynne, 1983:442; 

1988:53, figs. 1–14; Edding, 1988:153–161, figs. 2–10; Ramírez and 

Santelices, 1991:339; Silva et al., 1996b:233; Hoffman and Santelices, 

1997:361, fig. 100; L. Aguilar-Rosas et al., 2000:131; Pacheco-Ruíz 

and Zertuche-González, 2002:468; Pacheco-Ruíz et al., 2008:211; 

Wynne, 2014:20, fig. 5a–f.

Hypoglossum bipinnatifidum (Montagne) Kützing, 1849:876; Kützing, 

1866:6, pl. 15: figs. d–f.

Erythroglossum bipinnatifidum (Montagne) J. Agardh, 1898:176; Kylin, 

1924:31, fig. 22E; Navas, 1966:113, pl. 9: fig.2; Mikami, 1979:35, figs. 

1–15.

Delesseria woodii J. Agardh, 1872:54.

Branchioglossum woodii (J. Agardh) Kylin, 1924:8, fig. 2A; Kylin, 

1941:30, pl. 10: figs. 25, 26; Dawson, 1944a:321; Smith, 1944:335, 

pl. 86: figs. 5–8; Dawson, 1954e:344; Wagner, 1954:283, figs. 

1–19; Dawson, 1957a:8; 1959a:29; 1961b:444; 1962a:77, pl. 34: 

fig. 1, pl. 39: fig. 1; 1966a:28; Abbott and Hollenberg, 1976:637, 

fig. 577; Ramírez, 1982:22, figs. 14, 34, 35; Pacheco-Ruíz and 

Aguilar-Rosas, 1984:74; Stewart and Stewart, 1984:146; Stewart, 

1991:140; González-González et al., 1996:180; Mateo-Cid et al., 

2006:57.
NUMBER 96 • 217
218 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Branchioglossum macdougalii N. L. Gardner, 1927f:103, pl. 20: fig. 4; pls. 

33–34; González-González et al., 1996:179.

Branchioglossum battstroemii Levring, 1960:65, fig. 16; Santelices and Abbott, 1978:219.

Algae erect, flat, branched linear blades, monostromatic, except at the midrib, tapering to subacute to acute apices; blades up 

to 4.0 cm high and 1–2(–3) mm wide; primary percurrent main 

blade, with secondary lateral blades formed from margins; blades 

usually abruptly attenuated distally, with an acute apex; branching irregularly pinnate, alternate or subopposite, up to 3–4 orders; 

attached by discoid holdfast and occasionally by groups of rhizoids along blade margins. Lateral branches develop along margin of parent blade by conversion of an initial of a second-order 

cell row into a first order initial (develops midrib of new blade). 

Blade margins entire, but may appear dentate in early stages as 

lateral blades initiate. Midrib usually uncorticated above; corticated near basal region. Apical organization with a single apical 

cell; all cells of second-order rows have third-order cell rows, and 

all third-order cell row initials reach the blade margins.

Tetrasporangia tetrahedrally divided, 54–65 μm in diameter; irregularly arranged in 2 or more layers within long narrow sori, parallel to and on opposite sides of midrib in ultimate 

and subultimate blades. Gametangial thalli dioecious. Procarps 

(and cystocarps) restricted to midrib region of erect blades. Spermatangia in superficial patches on blade to both sides of midrib.

Habitat. On rocks or occasionally epiphytic on other 

algae, in crevices and tide pools; low intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Ensenada de San Francisco; Isla Tiburón (Islas de la Cintura) 

to Isla San Ildefonso (NNE of Punta San Antonita, Baja California Sur). Eastern Pacific: British Columbia to Baja California; 

Rocas Alijos; Chile. Southern Ocean (subantarctic): Kerguelen 

(Papenfuss, 1964b).

Type Locality. Valparaíso, Valparaíso Province, 

central Chile.

Remarks. Northern Gulf of California specimens 

referred to Branchioglossum bipinnatifidum are up to 4.0 cm 

long by 1.0–3.0 mm wide and are closest to B. macdougalii N. 

L. Gardner, a species originally described from the northern Gulf 

that is now generally considered conspecific. Gulf Branchioglossum bipinnatifidum are generally smaller and grow in warmer 

subtropical waters, whereas the northeastern Pacific and Chilean 

B. bipinnatifidum are found in cooler temperate waters. California specimens of B. bipinnatifidum are 2.5–7.0 cm tall (Smith, 

1944; Abbott and Hollenberg, 1976, both as B. woodii), and 

those from Chile are much larger and more robust, 13–18 cm tall 

and 4–8 mm wide (Mikami, 1979; Wynne, 1988; Ramírez and 

Santelices, 1991). Mikami (1979) suggested Delesseria bipinnatifida Montagne from Chile was a Branchioglossum. Wynne 

(1983) later transferred it to B. bipinnatifidum (Montagne) 

M. J. Wynne and also considered B. woodii and B. battstroemii

Levring (type locality: Chile) as synonyms.

The molecular testing of type locality material of B. bipinnatifidum (Valparaíso, Chile), B. woodii (type locality: Vancouver Island, British Columbia), and northern Gulf B. macdougalii 

(type locality: Puerto Libertad, Sonora), all currently considered 

conspecific, should clarify their phylogenetic relationships as 

well as the taxonomic status of the northern Gulf specimens referred to B. bipinnatifidum.

Branchioglossum undulatum E. Y. Dawson

FIGURE 104

Branchioglossum undulatum E. Y. Dawson, 1949b:17, figs. 39–42; 

1960a:51; Dawson et al., 1960a:50, pl. 33: fig. 2; 1960b:11, 24; Dawson, 1961b:444; 1962a:76, pl. 33: figs. 5, 6; 1966b:65; Abbott and 

Hollenberg, 1976:636, fig. 576; Wynne, 1988:63; Stewart, 1991:140; 

Serviere-Zaragoza et al., 1993a:483; Mateo-Cid and MendozaGonzález, 1994b:41; González-González et al., 1996:179; Wynne 

2014:20.

Algae of small, erect, delicate, flat, oblanceolate blades with a 

precurrent midrib, 1–2 cm tall, 2–5 mm wide; pinnately branched 

1–2 times; margins undulate or slightly ruffled, apices obtuse; 

blades monostromatic, except at the midrib; attached by a small 

discoid holdfast. Upper portion of blades broadened, somewhat 

lobed. Apical organization with all cells of second-order rows having third-order cell rows, and all third-order cell row initials reach 

the blade margins. Intercalary cell divisions are absent. Lateral 

“branches” (lobes) frequently developing along blade margin, giving the thallus an irregularly pinnate “webbed” appearance.

Tetrasporangia in irregular patches, sori between midrib 

and blade margin; of 2 or more cell layers. Tetrasporophyte 

blades narrower and more attenuated than cystocarpic or spermatangial blades. Gametangial thalli dioecious. Cystocarps projecting, hemispherical, 400–600 μm in diameter, ostiolate with 

flared rostrum (cf. Dawson, 1962a: pl. 33: fig. 5); restricted to 

midrib region of erect blades, 1 per blade. Spermatangial blades 

tending to be more undulate than cystocarpic blades. Spermatangia in elongated sori, diagonally oriented in relation to midrib; 

becoming partially confluent over blade.

Habitat. On rocks and tidal platform or epiphytic on 

Sargassum; low intertidal to shallow subtidal, down to 15 m depths.

Distribution. Gulf of California: Playa Hermosa, 

Puerto Peñasco to Punta Cirio; Isla San Ildefonso; Nayarit to 

Jalisco. Eastern Pacific: Carmel, central California to Todos Santos, Baja California Sur; Jalisco to Colima.

Type Locality. On a floating Macrocystis holdfast; 

San Miguel Passage, off NW end of Santa Rosa Island, California Channel Islands (Channel Islands National Park), southern 

California, USA.

Caloglossa (Harvey) G. Martens*

Delesseria subgen. Caloglossa Harvey, 1853:98.

Caloglossa (Harvey) G. Martens, 1869:234, 237, nom. cons.; King and Puttock, 1994:89; Krayesky et al., 2012:513.

Caloglossa (Harvey) J. Agardh, 1876:498.

* Contributed by James N. Norris and David M. Krayesky. D. M. 

Krayesky: Department of Biology, Slippery Rock University, Slippery 

Rock, Pennsylvania 16057, USA.
NUMBER 96 • 219

Apiarium Durant, 1850:18, nom. rej. (see Krayesky et al., 2011:51).

Algae are small, partially prostrate and erect, membranous, 

flat, narrow blades with a midrib, and usually regularly, subdichotomously branched. Thalli attached by rhizoidal filaments 

produced on ventral side of blades, and rhizoids either loosely 

arranged (not adhering to each other) or tightly compacted 

(strongly adhering to each other) into a peg-like attachment 

structure. Blades may be linear to obovate and slightly (sometimes just barely) to strongly constricted at the branching points 

(nodes) between comparatively long internodes. Main branches 

bearing exogenous indeterminate lateral branches, with endogenous and in some species also adventitious branches. The blade 

midrib is polystromatic, composed of elongated cells (lateral 

veins absent), and has single-layer (monostromatic) “wings” to 

each side of the midrib. Growth is apical, initially by transverse 

divisions of a wide apical cell, with all third-order cell row initials reaching the thallus margin; intercalary cell divisions absent 

in primary cell rows. The number of cell rows around the node 

are important characters for identifying Caloglosssa species.

Sporophytes develop tetrahedrally divided tetrasporangia, or 

in some bisporangia, in a series in the upper portions of branches, 

formed in a single layer outwards from lateral pericentral cells of 

the midrib (but not along blade margins). Asexual reproduction 

can also be apomictic. Gametangial thalli are monoecious or dioecious. Procarps with a 4-celled carpogonial branch and 1 group of 

sterile cells (and occasionally a second “group” of 1 cell occurs). 

Following fertilization, sessile cystocarps with a thin pericarp develop on the blade midribs. Spermatangia develop in superficial 

sori on blades between the midrib and blade margins in upper 

portions of terminal and subterminal blades.

Remarks. Most species of Caloglossa are found 

in the intertidal habitats of brackish waters of lagoons, salt 

marshes, esteros, and shallow protected bays. A few species are 

also in freshwater of riverine habitats. They can grow on prop 

roots or pneumatophores of mangroves, on other aquatic plants, 

or on mud or hard substrata, such as wood or pilings. Species 

are often associated with other red algae: Bostrychia Montagne 

(1842c), Catenella Greville (1830), and Murrayella F. Schmitz 

(1893). The Bostrychia–Caloglossa ecological association was 

termed “Bostrychietum” by Post (1936).

Two species of Caloglossa are reported in the Gulf of California, one referred to with a taxonomic query.

FIGURE 104. Branchioglossum undulatum: A. Habit. B. Closely spaced secondary blades initiating along margin of parent blade (A, B, JN4920, US Alg. Coll. microscope slide 4617).
220 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

KEY TO THE SPECIES OF CALOGLOSSA IN THE GULF OF CALIFORNIA

1a. Thallus generally broader, (0.9–)2.5–5.0 mm wide at median internode region; (1–)2–5 cell rows derived from the first 

axial cell of the main axis opposite a lateral branch. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. apomeiotica

1b. Thallus usually narrower, 0.5–1.4 mm wide at median internode region; (2–)3–7 cell rows derived from the first axial cell 

of the main axis opposite a lateral branch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. leprieurii?

Caloglossa apomeiotica J. A. West et Zuccarello

FIGURE 105

Caloglossa apomeiotica J. A. West et Zuccarello in West, Zuccarello, Pedroche and Karsten, 1994:383, figs. 1–15; Pedroche et al., 1995:116; Kamiya et al., 1998:368, tbls. 1, 2; Krayesky et al., 2011:53, figs. 26–33; 

Zuccarello et al., 2012:107, figs. 7–8; Pérez-Estrada et al., 2012:190; 

Krayesky et al., 2012:525, figs. 1–2, tbls. 1–2; Wynne, 2014:73.

Caloglossa apomeiotica nom. prov. sensu Karsten and West, 1993:730, figs. 

1–4, tbls. 1–2; West et al., 1993:148.

Caloglossa leprieurii sensu West and Zuccarello, 1990:236; GonzálezGonzález et al., 1996:303 (in part); Kamiya et al., 2003:478 (in part) 

[non Caloglossa leprieurii (Montagne) G. Martens, 1869:238; basionym: Delesseria leprieurii Montagne, 1840].

Algae small, prostrate to partially erect, 0.3–1.7 cm long; 

of flat, narrow, linear blades with a midrib, subdichotomously 

branched, slightly or occasionally strongly constricted at nodes 

(branching forks), 1.5–4.0 mm long, 0.9–2.5(–4.0) mm wide at 

median internode region; arising from a partially prostrate portion, attached by bundle of rhizoidal filaments issued from ventral 

surface and tightly appressed at base to form mound of compacted 

adhering cells, giving a holdfast-like appearance. Blade with a 

polystromatic midrib that consists of an axial cell filament with 2 

transverse and 2 lateral periaxial cells and monostromatic “wings” 

to either side. Endogenous branching present; adventitious branching absent. Lacking adaxial cell rows derived from first axial cell of 

lateral axis. One to two cell rows derived from nodal axial cell opposite lateral branch. Number of cell rows derived from first axial 

cell at main axis opposite the lateral branch (1–)2–5.

Asexual reproduction by uninucleate, apomeiotic bisporangia and tetrasporangia, subspherical, 50–56(–60) μm tall, 40–49 

μm in diameter. Sporangia formed in a single layer in regular 

rows. Other reproductive structures unknown in Gulf specimens.

FIGURE 105. Caloglossa apomeiotica: A. Thallus constricted at branching nodes (forks) (specimen from Brazil; Krayesky-73, US Alg. Coll.). 

B. Constriction at branch node, showing main and lateral axis. C. Ventral view of free rhizoidal filaments at base of bundle of tightly appressed 

rhizoids forming peg-like attachment structure. (B, C, specimens from Pacific Panama; Krayesky-64, US Alg. Coll.). 
NUMBER 96 • 221

Habitat. On mangrove prop roots of Rhizophora 

mangle Linnaeus, trunks and pneumatophores of Avicennia 

germinans (Linnaeus) Stearn and Laguncularia racemosa (Linnaeus) Gaertner f., and possibly on other aquatic vegetation in 

lagoons and estuaries; intertidal to very shallow subtidal.

Distribution. Gulf of California: Isla Espíritu 

Santo to Bahía Balandra and Estero Zacatecas, Ensenada de La 

Paz (vicinity of La Paz); Sinaloa to Jalisco. Eastern Pacific: Puerto 

San Carlos (Bahía Magdalena), Baja California Sur; Chiapas; 

Guatemala; El Salvador; Panama.

Type Locality. On prop roots of mangrove, Rhizophora mangle Linnaeus; Puerto San Carlos, within Bahía 

Magdalena, Baja California Sur, Pacific Mexico.

Remarks. Pacific Baja California Sur specimens referred to “Caloglossa leprieurii” by West and Zuccarello (1990) 

were later found to be a new species, C. apomeiotica J. A. West 

et Zuccarello, primarily because of their asexual mode of reproduction by apomictic bisporangia and tetrasporangia in cultured sporophytes (West et al., 1994). Kamiya et al. (2003) later 

concluded that the asexual C. apomeiotica was derived from C. 

leprieurii (Kamiya et al., 1998), and asexual reproduction alone 

was not considered sufficient to separate it from C. leprieurii. 

Subsequently, Krayesky et al. (2011) reestablished C. apomeiotica as a distinct species on the basis of morphological characters 

and new molecular data that placed it in a distinct clade.

Although C. apomeiotica is somewhat more robust, it is 

similar to C. leprieurii?. By examining the larger end of the range 

of the widths and the number of cell rows derived from the first 

axial cell of the main axis opposite a lateral branch, the two can 

be separated: C. apomeiotica has blades that are 2.5–5.0 mm 

wide with 2–5 cell rows, whereas C. leprieurii has blades that are 

0.5–1.4 mm wide with 3–7 cell rows.

Caloglossa leprieurii? (Montagne) G. Martens

Delesseria leprieurii Montagne, 1840:196–197, pl. 5: fig. 1.

Caloglossa leprieurii (Montagne) G. Martens, 1869:234, 237; Krayesky et 

al., 2011:47, figs. 3–12; Krayesky et al., 2012:525; Wynne, 2014:71.

Caloglossa leprieurii (Montagne) J. Agardh, 1876:499; Ortega et al., 

1987:75, pl. 8: figs. 37–38, pl. 9: fig. 39; González-González, 1993:442; 

Pedroche et al., 1995:115; González-González et al., 1996:303, 385; 

Dreckmann et al., 2006:155; Fernández-García et al., 2011:60.

Hypoglossum leprieurii (Montagne) Kützing, 1849:875.

Algae small, prostrate to partially erect, 0.8–2.0 cm long; 

of flat, narrow, linear blades with a midrib, subdichotomously 

branched, slightly or occasionally strongly constricted at branching nodes, 1.5–4.0 mm long, 0.5–1.4 mm wide at median internode region; arising from a partially prostrate portion, attached 

by tightly adhering rhizoidal filaments issued from base of blade 

to form a compact, peg-like mound; giving a holdfast-like appearance. Blade midrib of an axial cell filament with 2 transverse 

and 2 lateral periaxial cells and monostromatic “wings” to either 

side. Endogenous branching present; adventitious branching absent. Lacking adaxial cell rows derived from first axial cell from 

lateral axis. One to two cell rows derived from nodal axial cell 

opposite lateral branch. Number of cell rows from first axial cell 

at main axis opposite the lateral branch (2–)3–7 (description 

after Krayesky et al., 2011).

Tetrasporangia and bisporangia, 55–65(–80) μm tall, 35–56 

μm in diameter, formed in a single layer in regular rows. Cystocarps forming near blade apices. Male reproductive structures 

not observed.

Habitat. Epiphytic on aquatic vegetation and mangrove (mangle) pneumatophores and prop roots; intertidal to 

very shallow subtidal.

Distribution. Gulf of California: Laguna Agiabampo, Sonora and Sinaloa. Eastern Pacific: Chiapas; Costa Rica.

Type Locality. Sinnamary, northwest of Cayenne, 

French Guiana.

Remarks. Caloglossa leprieurii, described from the 

western Atlantic, is probably widespread in tropical waters of 

the eastern Pacific, and Indian oceans (Krayesky et al., 2011, 

2012). Specimens identified within a broadly defined “C. leprieurii” in the Americas by previous investigators were shown to 

actually encompass four distinct species that were morphologically and molecularly different from one another (Krayesky et 

al., 2011, 2012).

Caloglossa leprieurii has been reported in the southern Gulf 

from Laguna Agiabampo, Sonora and Sinaloa (Ortega et al., 

1987). Gulf of California specimens are tentatively referred to 

“C. leprieurii?” with a taxonomic query until more collections 

from Laguna Agiabampo and elsewhere in the Gulf can be made 

to test if C. leprieurii is present by morphological and molecular 

comparisons to type locality C. leprieurii and C. apomeiotica. It 

is also possible there are other species to be found within a Gulf 

“C. leprieurii complex.”

Erythroglossum J. Agardh

Erythroglossum J. Agardh, 1898:174.

Algae may be erect or decumbent and composed of 1 or 

more blades, with polystromatic midribs that are indistinct in 

some parts of the thallus. Lateral veins present or lacking, and 

margins may be dentate (toothed), especially in distal portions. 

Blades commonly stipitate and simple or branched from the margins. Growth is from single apical cells, with intercalary cell divisions in the primary and higher order cell rows.

Tetrasporangia arranged in sori, at maturity linear and parallel to margins. Gametophytes dioecious, procarps composed of 

two 4-celled carpogonial branches with a single group of sterile 

cells per supporting cell; carposporophyte with carposporangia 

in terminal branched chains. Cystocarps scattered over blade. 

Spermatangia in linear sori parallel to margins.

One species of Erythroglossum is reported in the northern 

Gulf of California.

Erythroglossum californicum (J. Agardh) J. Agardh

FIGURE 106

Delesseria californica J. Agardh, 1885:69.
222 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Erythroglossum californicum (J. Agardh) J. Agardh, 1898:176; Kylin, 

1941:31, pl. 10: fig. 28; Dawson, 1962a:93, pl. 46: fig. 1; Abbott and 

Hollenberg, 1976:648, fig. 509; Stewart, 1991:143; González-González 

et al., 1996:199; Pacheco-Ruíz et al., 2008:212; Wynne, 2014:191.

Psammophyllum californicum (J. Agardh) P. C. Silva et R. Moe in Silva, 

1979:330, nom. invalid.

Erythroglossum obcordatum E. Y. Dawson et Neushul, 1966:183, pl. 43: 

figs. 4, 5; Scagel et al.,1989:293.

Algae erect, up to 4.0 cm tall, of ribbon-like, narrow, more 

or less linear, delicate blades, 2.5–3.0(–4.0) mm wide, subdichotomously to irregularly branched, up to 4(–6) orders, with an 

apparent, polystromatic midrib and without lateral veins; margins irregularly denticulate, often eroded; apical margins mostly 

irregular; apical cell inconspicuous; thalli attached below by a 

small, compact holdfast.

Tetrasporangial sori on both sides of midrib; initially discrete and circular to oval, later becoming confluent and more 

linear, mostly near the blade margins. Cystocarpic and spermatangial thalli not seen in Gulf specimens. 

Habitat. Shallow subtidal, down to 5 m depths.

Distribution. Gulf of California: El Desemboque 

to Isla San Esteban. Eastern Pacific: Oregon (Hansen, 1997); 

Anacapa Island (California Channel Islands); Santa Barbara to 

San Diego, southern California.

Type Locality. Santa Barbara, Santa Barbara 

County, southern California, USA.

Remarks. The northern Gulf specimens are tentatively referred to Erythroglossum californicum. Their relationship 

to type locality material of E. californicum and to Anisocladella 

pacifica Kylin (1941) is in need of further investigation. The “E. 

californicum” as identified from Oregon (Doty, 1947) and central California (Smith, 1944, 1969) appear to be A. pacifica (Abbott and Hollenberg, 1976), a species that has been considered 

conspecific with E. californicum (Gabrielson et al., 2012).

In using the name Psammophyllum californicum, Silva and 

Moe (in Silva,1979) based it on Anisocladella pacifica and considered Delesseria californica an earlier synonym; unfortunately, 

the generic name Psammophyllum has not been validly published. 

The taxonomic status of the southern California E. californicum

is in need of further study, and as Stewart (1991) indicated, its 

name and taxonomic position are likely to be changed.

Grinnellia Harvey

Grinnellia Harvey, 1853:91.

Algae are membranous blades, upper regions monostromatic, with a polystromatic midrib (conspicuous throughout or 

at least in lower portion of the blade). Blades are usually simple 

(unbranched) or sometimes have proliferous bladelets near base 

or are occasionally irregularly branched distally if wounded. 

Growth is from a prominent apical cell that divides transversely 

and later intercalary divisions within secondary and higher order 

cell rows. The lateral pericentral cells divide transversely, forming 

second-order cell rows that produce third-order rows; some, but 

not all, of the third-order row initials reach the thallus margin.

Tetrasporangia are tetrahedrally divided, cut off with small 

cortical cells toward both of the blade’s surfaces in small sori, 

and scattered over the primary blade below the apices. Gametangial thalli are dioecious. Minute bladelets are scattered over the 

primary blade, with procarps produced from the midrib of the 

bladelets. Cystocarps are hemispherical, ostiolate, and project on 

either side of the bladelet (often appearing to be on a stalk) immersed in the surface of the parent blade. Spermatangia develop 

in small sori, scattered on one or both of the blade surfaces.

One species of Grinnellia occurs in the northern Gulf of 

California.

Grinnellia lanceolata E. Y. Dawson

FIGURE 107

Grinnellia lanceolata E. Y. Dawson, 1944a:322, pl. 47: fig.6; 1962a:84, pl. 

39: fig. 5; Wynne, 1985a:169, figs. 7–12; Pacheco-Ruíz and ZertucheGonzález, 2002:468; Fernández-García et al., 2011:62; Wynne, 

2014:105.

Apoglossum punctatum E. Y. Dawson, 1966b:65, fig. 6B.

Blades erect, 2.5–6.0 cm tall, narrowly cuneate above a 

short stipe, membranous, monostromatic except for percurrent, 

polystromatic midrib of larger elongated cells. Blades initially 

ovate-elliptical, then broadening up to 1.0–3.0 cm wide; with 

entire margins. Growth from an apical cell and also intercalary 

cell divisions in second-order and higher cell rows; intercalary 

divisions absent in first-order rows. Lateral pericentral cells divide transversely.

FIGURE 106. Erythroglossum californicum: Habit (JN-6578a, US 

Alg. Coll.-217358).
NUMBER 96 • 223

Tetrasporangia tetrahedrally divided, 60–70 μm long, 

45–60 in diameter; in small, discrete sori scattered over the blade 

surface (punctate) on both sides of midrib. Procarps develop on 

midrib of fertile bladelets. Cystocarps up to 1 mm in diameter; 

appear to be scattered over blade, but actually borne on midline 

of very short, fertile bladelets that arise off main blade. Spermatangia in irregular, angular sori; scattered over blade.

Habitat. On rocks; shallow subtidal.

Distribution. Gulf of California: Bahía de Los 

Ángeles; Isla Salsipuedes (Islas de San Lorenzo); Puerto Escondido; 

Punta Gorda, Bahía San Jose del Cabo. Eastern Pacific: Panama.

Type Locality. Punta Gorda, NE end of Bahía San 

Jose del Cabo, Baja California Sur, Gulf of California, Mexico.

Remarks. Although previously Grinnellia lanceolata was considered endemic in the Gulf of California, it was 

recently reported in Pacific Panama (Littler and Littler, 2010). 

Two Gulf of California species, G. lanceolata and the endemic 

Apoglossum punctatum, were noted by Dawson (1966b) to be 

“related.” Wynne (1985a) later observed both to have the same 

apical growth pattern and small discrete tetrasporangial sori, 

characteristics of Grinnellia, and considered them conspecific. 

Hypoglossum Kützing 

Hypoglossum Kützing, 1843:444. 

Thalli composed of flat blades, usually erect and attached 

by discoid holdfasts or secondarily by marginal rhizoids. Blades 

are membranous, monostromatic (except in midrib and fertile regions), and lack lateral veins. New blades are issued singularly or 

in pairs from the midrib (primary cell row) of older blades and are 

similar in structure to the supporting parent blade. The percurrent midrib can become corticated in some species and can form 

a thickened “stipe” basally if the blade erodes. Branching is endogenous, restricted to the midrib (except in H. anomalus). Most 

species are monopodially organized. Axial filament of cells with 2 

lateral pericentral cells and 2 transverse pericentral cells. The lateral pericentral cells form second-order cell rows with one of two 

types of apical organization, either (1) all cells of second-order 

rows bear third-order rows or (2) not all cells of second-order 

rows bear third-order cell rows. All cell rows that are initiated 

reach blade margins. Almost all species are without intercalary 

cell divisions (only one species, H. sagamianum Yamada, 1941, 

has secondary cell rows with intercalary cell division).

FIGURE 107. Grinnellia lanceolata: A. Habit of a damaged specimen that has regenerated some blades. B. Habit of narrow lanceolate 

blade with tetrasporangia (type specimen, after Dawson, 1944a, pl. 

47: fig. 6). C. Blade apex showing apical organization; note that not 

all third-order cell rows reach blade margin and the lateral pericentral cells divide transversely. D. Small discrete tetrasporangial sori, 

with a limited number of tetrasporangia, distributed over blade (A, 

C, D, EYD-26143, US Alg. Coll. microscope slide 779, type of Apoglossum punctatum). 
224 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Tetrasporangia can be borne in either (1) rows with cover 

cells not corticating the sori or (2) a random arrangement with 

cover cells corticating the sori. Tetrasporangia are in one or more 

cell layers, usually in sori along the sides of the blade midrib 

or extending over it. Gametophytes are dioecious. Procarps restricted to midrib. Cystocarps are borne along the midline and 

are emergent and prominent, with an ostiole that often has a 

rostrum. The rostrum in different species ranges from a slight 

collar to a long “neck.” Spermatangia formed in small or large 

confluent sori between the midrib and blade margin. One species, Hypoglossum attenuatum, with two varieties, is reported in 

the northern Gulf of California.

KEY TO THE VARIETIES OF HYPOGLOSSUM ATTENUATUM IN THE NORTHERN GULF OF CALIFORNIA

1a. Lanceolate blades abundantly branched; blades slender 1–2(–2.5) mm wide . . . . . . . . . H. attenuatum var. attenuatum

1b. Lanceolate blades sparsely branched (usually without blades in lower portions); blades longer and wider, up to 6 mm 

wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. attenuatum var. abyssicolum

Hypoglossum attenuatum N. L. Gardner var. attenuatum

Hypoglossum attenuatum N. L. Gardner, 1927f:104, pl. 20: fig. 3, pls. 35, 

36; Dawson, 1944a:321; 1960a:51; 1961b:445; 1962a:78; GonzálezGonzález et al., 1996:228; Anaya-Reyna and Riosmena-Rodríguez, 

1996:864, tbl. 1; Pacheco-Ruíz and Zertuche-González, 2002:468; 

Pacheco-Ruíz et al., 2008:212; Fernández-García et al., 2011:62; 

Wynne, 2014:29.

Blades erect, membranous, and lanceolate, dark pink to 

greenish in color, 2.5–7 cm tall and 1–2(–2.5) mm wide, mostly 

richly branched; arising from a small discoid holdfast. Blades 

monostromatic (except at the midrib), slender, linear-lanceolate, 

usually tapering to an acute apex; branched from midrib, up to 

3(–4) orders. Blades of female thalli may be shorter and broader 

with more obtuse apices. Apical organization with second-order 

cells all issuing third-order cell rows, all third-order row initials 

reach the blade margins.

Tetrasporangia in sori; produced in 2 or more cell layers. 

Cystocarps prominent, protuberant, borne above midrib on blade 

surface; often a single cystocarp per blade, enclosed in a pericarp, 

ostioles with collar-like rostrum. Spermatangia unknown.

Habitat. On rocks, epiphytic on or entangled with 

other algae; low intertidal to shallow subtidal, down to 8 m 

depths (also dredged from 12–80 m depths; Dawson, 1944a).

Distribution. Gulf of California: Rocas Consag; 

Punta Pelicano to Guaymas; Cabo Pulmo-Los Frailes to Cabo 

San Lucas. Eastern Pacific: Isla Guadalupe; Bahía San Quintín, 

Baja California to Oaxaca; Panama; Colombia; Ecuador; Chile. 

Western Pacific: China; Vietnam.

Type Locality. Puerto Libertad, Sonora, Gulf of 

California, Mexico (Gardner, 1927f).

Hypoglossum attenuatum var. abyssicolum (W. R. Taylor) 

E. Y. Dawson

FIGURE 108

Hypoglossum abyssicolum W. R. Taylor, 1945:277, pl. 89, figs. 1, 2; Bernecker, 2009:CD-Rom p. 66.

Hypoglossum attenuatum var. abyssicolum (W. R. Taylor) E. Y. Dawson, 

1962a:77, pl. 34: fig. 3; Norris, 1973:15; Schnetter and Bula-Meyer, 

1982:169, pl. 30: fig. 4; Stewart and Stewart, 1984:146; HuertaMúzquiz and Mendoza-González, 1985:52; Mateo-Cid and MendozaGonzález, 1992:22; Serviere-Zaragoza et al., 1993a:484; GonzálezGonzález et al., 1996:228; CONANP, 2002:138; Fernández-García et 

al., 2011:62; Wynne, 2014:29.

Hypoglossum attenuatum sensu Dawson, 1944a:321 [in part; non Hypoglossum attenuatum var. attenuatum N. L. Gardner, 1927f:104].

Algae of narrow delicate blades up to 12 cm long; sparingly branched from midrib; usually lacking branches in lower 

portions; to each side of polystromatic midrib blade 1 cell thick 

and without lateral veinlets, midrib becomes faint in ultimate 

branchlets; blades mostly 2.5–7.5 cm long and up to 6 mm wide; 

blades shorter and narrower with each successive order; tapering 

to base and apices. Blades of cystocarpic thalli shorter and wider, 

with broadly obtuse apices.

Tetrasporangia in oblong sori, up to 3 mm long, on both 

sides of midrib. Cystocarps usually singular on midrib of ultimate 

and subultimate blades; 0.9–1.2 mm in diameter. Spermatangia 

formed in small sori between the midrib and blade margin.

Habitat. Subtidal; 10–40 m depths.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda; Isla San Esteban; Isla Tiburón; Bahía 

de Loreto to Punta Los Frailes; Sinaloa to Nayarit; Islas Marías 

(Islas Tres Marías). Eastern Pacific: Isla Guadalupe to Laguna de 

San Ignacio, Baja California; Oaxaca; Costa Rica; Isla Gorgona, 

Colombia; Galápagos Islands.

Type Locality. Dredged from 56 m depth; off Post 

Office Bay, Isla Floreana (Isla Santa María), Galápagos Islands, 

Ecuador.

Myriogramme Kylin

FIGURE 109D

Myriogramme Kylin, 1924:55.

Blades may be foliose, simple, or lobed or variously 

branched, usually erect or with erect and prostrate portions, and 

are with or without midribs or macroscopic veins; microscopic 

veins absent. Some species have a compressed to cylindrical 

stipe; others lack a stipe; attached by small holdfasts or secondarily by ventral or marginal rhizoids. Blades are typically monostromatic above and may become tri- to polystromatic below, 

and have polystromatic veins, reproductive structures, and stipes 
NUMBER 96 • 225

as well as near their base. Growth is diffuse, from marginal and 

intercalary meristems. Apical cells divide obliquely, becoming indistinguishable from marginal row initials. Cells of blade are polygonal in surface view; in transection arranged in vertical rows 

in polystromatic portions.

Tetrasporangia are tetrahedrally divided and borne in small 

circular, elliptical, linear or irregular sori grouped along the 

blade margins. Tetrasporangial sorus is covered by 2–3 layers of 

cortical cells, with tetrasporangia developed primarily from central cells and also from the inner cortical cells. Gametophytes are 

FIGURE 108. Hypoglossum attenuatum var. abyssicolum: A. Habit (JN-4722, US Alg. Coll.-160075). B. Blade apex showing all second-order 

row cells bear third-order cell rows and all third-order row initials reach the blade margin (in the photo second-order row initials are wedgeshaped at the blade margin, and third-order initials are elongated) (EYD-26163, US Alg. Coll. microscope slide 774). C. Several blades developing from midrib of parent blade (JN-5156a, US Alg. Coll. microscope slide 4609). D. Protuberant cystocarp borne on midline of blade with a 

short collar-like rostrum forming ostiole. E. Spermatangia in sori, with these in disjunct patches (D, E, EYD-26117, US Alg. Coll. microscope 

slide 793). 
226 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

dioecious. Procarps, a 4-celled carpogonial branch with 2 sterilecell groups, are scattered on blades. Carposporophyte with 

extensive, branched basal fusion cell, carposporangia borne terminally in chains and occasionally also with lateral clusters. Cystocarps with ostiolate pericarp, several cells thick. Spermatangial 

sori small, produced in monostromatic areas, later enlarging as 

they become confluent. Spermatangial sori near blade margins 

on both sides of blade, with cells bearing layer of cortical initials 

that produce elongate spermatangia.

Three species of Myriogramme are known to occur in the 

northern Gulf of California.

KEY TO THE SPECIES OF MYRIOGRAMME IN THE NORTHERN GULF OF CALIFORNIA

1a. Blades simple, undivided; margins with rounded, “scalloped” lobes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. caespitosa

1b. Blades branched with a stipitate base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Blades divaricately dichotomously branched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. divaricata

2b. Blades developed sympodially, somewhat auriculately “flared out” from top of stipe . . . . . . . . . . . . . . . M. auricularis

Myriogramme auricularis E. Y. Dawson

FIGURE 109B,C

Myriogramme auricularis E. Y. Dawson, 1966b:66, fig. 6I [type specimen]; 

González-González et al., 1996:244; Wynne, 2014:178.

Blade membranous, mostly erect, up to 2.5 cm tall and to 

2.5 cm wide; blades flared somewhat auriculately from top of 

stipe or secondary holdfasts; stipe initially short with a knobby 

holdfast, elongating up to 6 mm upon repeated grazing and 

FIGURE 109. Species of Myriogramme: A. Myriogramme divaricata: Thallus dichotomously lobed with rounded apices 

(JN-5583a, US Alg. Coll.-217360). B, C. Myriogramme auricularis: B. Habit. C. Tetrasporangial sori near thallus margins 

(B, C, EYD-26167, US Alg. Coll. microscope slide 771, type of M. auricularis). D. Myriogramme sp.: Meristematic margin 

of blade (JN-4901, US Alg. Coll. microscope slide 5289). 
NUMBER 96 • 227

branch regeneration, with successive blades tending to develop 

sympodially; secondary discoid or peg-like attachments may 

develop if appressed to hard substratum or solid objects or 

removed from stipe, also formed between overlapping blades. 

Blades deeply, irregularly palmately lobed, with undulate, entire 

margins; lacking midrib or veins; monostromatic throughout, 

except thickened immediately above stipe and polystromatic in 

basal region.

Tetrasporangia in oval to elongate tetrasporangial sori, just 

inside blade margins along outer lobes. Cystocarpic and spermatangial thalli unknown.

Habitat. Subtidal; dredged from 8–30 m depths.

Distribution. Gulf of California: Isla Rasa (Isla 

Raza) and Isla San Lorenzo (Islas de la Cintura).

Type Locality. Isla San Lorenzo (“Isla San Lorenzo 

del Sur”; southern island of Islas de San Lorenzo), off east coast 

of Baja California, Gulf of California, Mexico.

Myriogramme caespitosa E. Y. Dawson

Myriogramme caespitosa E. Y. Dawson, 1949b:19, fig. 8; Dawson et al., 

1960a:68, pl. 33: fig. 5; 1960b:26; Dawson, 1961b:446; 1962a:96, 

pl. 47: fig. 4; Abbott and Hollenberg, 1976:654, fig. 597; GonzálezGonzález et al., 1996:244; L. Aguilar-Rosas et al., 2000:131; PachecoRuíz and Zertuche-González, 2002:468; Mateo-Cid et al., 2006:57; 

Pacheco-Ruíz et al., 2008:212; Wynne, 2014:178.

Myriogramme osorioi E. Y. Dawson, 1950b:158, figs. 18, 19; 1961b:447; 

1962a:96, pl. 47: figs. 1, 2; 1966b:66; Abbott and North, 1972:76; 

González-González et al., 1996:244.

Blades small, delicate, rose pink, erect or repent, to 1.0 (-

3.0) cm high and 5–8 mm wide; of several overlapping blades, 

forming clumps. Blades monostromatic, except in basal region, 

veins completely lacking. Blades undivided or palmately lobed, 

with rounded scalloped lobes, with smooth, ruffled, or undulate margins. Blades occasionally attached to each other by small 

accessory discs. Cells usually angular, 50–70 μm in diameter in 

mature portions of blade.

Tetrasporangia in circular to oval sori. Cystocarps scattered, 

with pericarp and conspicuous “beaked” ostiole. Spermatangial 

sori often becoming confluent.

Habitat. On rocks; low intertidal to shallow subtidal, down to 13 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to Isla Coronado (Isla Smith), off north end of Bahía de Los 

Ángeles; Isla Estanque to Isla Las Ánimas (Isla San Lorenzo del 

Norte) and Isla San Lorenzo (both Islas de San Lorenzo); Isla 

Patos (off N end of Isla Tiburón); Isla Partida. Eastern Pacific: 

Santa Rosa Island and Santa Cruz Island (California Channel 

Islands), southern California to Isla Magdalena, Baja California Sur.

Type Locality. On a floating Macrocystis holdfast; in San Miguel Passage, off Santa Rosa Island, California 

Channel Islands (Channel Island National Park), southern California, USA.

Myriogramme divaricata E. Y. Dawson

FIGURE 109A

Myriogramme divaricata E. Y. Dawson, 1944a:323, pl. 47: fig. 5; 1962a:97, 

pl. 40: fig. 5, pl. 42: fig. 2; Pacheco-Ruíz and Zertuche-González, 

2002:468; Pacheco-Ruíz et al., 2008:212; Wynne, 2014:179.

Blades delicate, small (to 3 cm), from short stipe (1.0 mm), 

membranous, divaricately dichotomously branched, with more 

or less rounded or truncate tips. Blades monostromatic without 

midrib or veins.

Tetrasporangia in small sori. Carposporangial and spermatangial thalli unknown.

Habitat. On rock or entangled with other algae; 

shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Roca Consag; Puerto Refugio, Isla Ángel de la Guarda to 

Isla Estanque; Isla Coronado and Isla la Ventana, Bahía de Los 

Ángeles.

Type Locality. Puerto Refugio, Isla Ángel de la 

Guarda (Islas de la Cintura), Gulf of California, Mexico.

Remarks. Myriogramme divaricata, a Gulf of California endemic species, was only known from the type (Dawson, 

1962a). Additional subtidal collections extend its known distribution from Rocas Consag (JN-3128, US Alg. Coll. microscope 

slides 4637, 4638) to Isla Estanque, off the southern end of Isla 

Ángel de la Guarda (JN-5583a, US Alg. Coll.-217360).

Phycodrys Kützing

Phycodrys Kützing, 1843:444.

Thallus leaf-like or foliose blades, arising from a discoid 

holdfast or creeping entangled stolons. Blades simple, lobed in 

upper portions, or producing secondary bladelets along margins. Blades monostromatic except for midrib regions, lateral 

veins, and holdfasts or some species tristromatic. Midribs conspicuous and lateral veins present, often paired and opposite, 

alternate or may be irregularly arranged; micropscopic veins 

lacking or faint. Midrib with or without cortication, without 

descending rhizoids; composed of more or less rectangular cells 

in cross section. Growth by means of a single transversely dividing apical cell, intercalary cell divisions in primary and higherorder cell rows.

Tetrasporangia in rounded sori on proliferous bladelets 

from margin or on main blade surface between lateral veins. 

Tetrasporangia in 2 layers, produced laterally from inner cortical cells, covered by layer of outer cortical cells. Gametophytes 

dioecious. Procarps with 4-celled carpogonial branch and 2 

sterile-cell groups. Cystocarps with basal fusion cell, branched 

gonimoblast with terminal chains of carposporangia, surrounded 

by 3- to 8-cells-thick pericarp with ostiole. Cystocarps scattered 

over blade surfaces. Spermatangia in rounded sori scattered over 

blade.

Three species of Phycodrys, all endemic, are known in the 

northern Gulf of California.
228 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

KEY TO THE SPECIES OF PHYCODRYS IN THE NORTHERN GULF OF CALIFORNIA

1a. Blades with lateral veins irregularly branched off midrib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. amplissima

1b. Blades with lateral veins regularly, oppositely branched off midrib . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Blades usually simple with smooth margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. simplex

2b. Blades often branched from margins with occasional rhizoidal bundles along blade margins . . . . . . . . . . . . P. lucasana

Phycodrys amplissima E. Y. Dawson

FIGURE 110

Phycodrys amplissima E. Y. Dawson, 1962a:91, pl. 44, pl. 45:figs. 2, 3; 

González-González et al., 1996:247; Pacheco-Ruíz and ZertucheGonzález, 2002:468; Mateo-Cid et al., 2006:57; Pacheco-Ruíz et al., 

2008:212; Wynne, 2014:208.

Thalli erect and membranous foliose blades, relatively large, 

mostly 10–13 cm (largest up to 27 cm) tall and to 16(–20) cm 

wide, symmetrical to asymmetrical, with conspicuous midrib and 

irregularly arranged lateral veins (becoming faint above), from a 

short stipe attached by a stoloniferous holdfast. Blades monostromatic, except for polystromatic region near midrib, veins, 

stipe, and holdfast; margins undulating and denticulate, with 

minute irregular proliferations (“teeth”) along margin. Growth 

from apical cell with intercalary divisions in all orders of cell 

rows. Lateral pericentral cells producing second-order rows that 

reach the blade margin, and further intercalary divisions form 

the blade.

Tetrasporangial sori start out small and rounded, then 

enlarge, some becoming confluent and somewhat elliptical in 

shape, over 1 mm long. Mature tetrasporangia 65–80 μm long. 

Gametophytes dioecious. Mature cystocarps up to 600–750 μm 

in diameter, ostiolate, scattered over the blade. Spermatangial 

sori forming rounded to irregularly shaped patches, 1–2 mm in 

diameter.

Habitat. On rocks; intertidal to subtidal, 10–36 m 

depths.

Distribution. Gulf of California: Puerto Peñasco; 

El Desemboque to Isla San Esteban.

Type Locality. Off Isla San Esteban (Islas de la 

Cintura) at 10–36 m depths, Gulf of California, Mexico.

Remarks. The endemic Phycodrys amplissima is 

apparently restricted in distribution to the northern Gulf of 

California.

Phycodrys lucasana E. Y. Dawson

Phycodrys lucasana E. Y. Dawson, 1962a:88, pl. 37: figs. 7, 8, pl. 43: 

fig. 1; 1966b:66; González-González et al., 1996:247; Wynne, 

2014:208.

Blades membranous, erect, up to 5 cm tall and to 13 mm 

wide, monostromatic apart from midrib and slender opposite 

lateral veins. Blade usually single and branched above a short 

terete stipe (2 mm); attached by discoid holdfast. Branches arise 

from blade margins, branches similar to primary blade. Margins at first denticulate, these “teeth” later developing into terete, 

simple or branched rhizoidal bundles.

Tetrasporangial sori small, scattered on blades. Sexual reproduction unknown.

Habitat. On rocks; subtidal, dredged 12 to 36 m 

depths.

Distribution. Gulf of California: Isla Salsipuedes; 

Bahía de San Lucas.

Type Locality. Dredged, 36 m depth, Bahía de San 

Lucas, Baja California Sur, Gulf of California, Mexico.

Phycodrys simplex E. Y. Dawson

FIGURE 111

Phycodrys simplex E. Y. Dawson, 1962a:90, pl. 38: figs. 2, 3; 1966b:66; 

González-González et al., 1996:248; Pacheco-Ruíz et al., 2008:212; 

Wynne, 2014:209.

Algae upright, mostly 4–5.5 cm tall, consisting of several 

stipitate blades (each with a short stipe 3–5(–10) mm long), that 

arise from a basal, terete, common stipe 5–10 mm long. Blades 

simple and lanceolate with evident midrib and faint slender opposite lateral veins. Older blades 1.0–2.5 cm wide, gently tapering to apex, with midrib to 1 mm wide at base of blade; margins 

smooth, slightly undulate.

Reproduction not observed.

Habitat. On rocks; subtidal, dredged 20 to 44 m 

depths. 

Distribution. Gulf of California: channel between Islas Mejia and Isla División (NW end of Isla Ángel de 

la Guarda); Puerto Refugio, Isla Ángel de la Guarda; Isla San 

Lorenzo (Isla San Lorenzo del Sur). 

Type Locality. Dredged from 22–44 m depths; 

Puerto Refugio, Isla Ángel de la Guarda (Las Islas de la Cintura), 

Gulf of California, Mexico.

Remarks. Phycodrys simplex is an endemic species, 

thus far only known in the northern Gulf of California. Although 

its reproduction remains unconfirmed, Dawson (1966b:66) 

noted numerous minute bladelets (to 350 μm long) that were 

“sterile” but similar to sporangial bladelets.

Polyneurella E. Y. Dawson

Polyneurella E. Y. Dawson, 1944a:322.

Blades membranous, from branched stipe, with entire 

margins; attached by a small discoid holdfast. Blades mostly 

monostromatic; midribs lacking but with longitudinal veins and 

veinlets, inconspicuous (microscopic) above, more visible (macroscopic) in lower portion of mature blades. Veins indistinctly 

anastomosing in basal portion of blade; in upper portions veins 
NUMBER 96 • 229

somewhat parallel; veins not always connected (discontinuous). Blades arising from subcylindrical stipe-like lower portion. 

Growth by means of an apical cell, with intercalary divisions in 

primary cell row.

Tetrasporangial sori small, scattered on blades. Cystocarps 

scattered over blade surface. Spermatangia unknown.

A monotypic genus, its one species, with two varieties, is 

known in the northern Gulf of California.

KEY TO THE VARIETIES OF POLYNEURELLA IN THE GULF OF CALIFORNIA

1a. Blades above a short, branched stipe, attached by a small discoid holdfast; blade margins smooth . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. hancockii var. hancockii

1b. Blade above a prostrate, fleshy basal structure; with groups of rhizoids and proliferous branchlets along blade margins

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. hancockii var. rhizoidea

FIGURE 110. (Left, above) Phycodrys amplissima: A. Large, 

somewhat asymmetrical blade with stoloniferous holdfast, midrib 

with lateral, irregularly opposite veins, and numerous scattered 

cystocarps (JN-6578b, US Alg. Coll.-217347). B. Denticulate 

margin, showing short teeth along blade margin (isotype, EYD21580, US Alg. Coll. microscope slide 635).

FIGURE 111. Phycodrys simplex: Habit of lanceolate blades 

borne off terete stipes (holotype: EYD-183-40, AHFH, now UC).
230 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Polyneurella hancockii E. Y. Dawson var. hancockii

FIGURE 112

Polyneurella hancockii E. Y. Dawson, 1944a:323, pl. 47: figs. 1 [type 

specimen], 2; 1961a:446; 1962a:85, pl. 40; figs. 3, 4; 1966b:66; Abbott and Hollenberg, 1976:651, fig. 594; González-González et al., 

1996:252; Anaya-Reyna and Riosmena-Rodríguez, 1996:864, tbl. 1 

[as “Polyneura hancockii”]; Pacheco-Ruíz et al., 2008:212; Wynne, 

2014:149, fig. 69.

Blades erect, usually in a clump from branched stipe, rosy 

to pink, ovate, 2.0–7.5 cm tall and to (2–)3–6 cm wide, margins 

usually entire, with gentle taper to apices; some blades may 

become lacerated and then regrow, appearing lobed near top. 

Thallus usually 1 larger primary blade, and smaller blades developed along semiterete to compressed stipe-like portion that 

arises from discoid holdfast. Blades monostromatic with longitudinal veins and veinlets (distromatic), these microscopic in 

upper portions of blade and macroscopic in mature portions. 

Abundant secondary pit connections among adjacent vegetative cells.

Tetrasporangia in small, more or less circular to irregular 

sori (enlarging as blades mature), distributed in mid- to upper 

parts of blade toward margins. Gametophytes apparently dioecious. Single female blade observed slightly wider than tetrasporic blades, veins visible with slightly greenish cast against 

pink-purplish blade. Cystocarps 500–600 μm in diameter, scattered on blade; protruding on both sides of blade. Carposporangia elongate, to 100 μm long by 40 μm wide.

Habitat. On rocks; subtidal, 15–40 m depths.

Distribution. Gulf of California: Isla Ángel de la 

Guarda; Canal de Infiernillo (midway between Isla Tiburón and 

Campo Viboras, Sonora); Punta Los Frailes. Eastern Pacific: Carmel Submarine Canyon (south of Monterey Canyon), Monterey 

Bay National Marine Sanctuary, central California.

Type Locality. Dredged from 22–44 m depths;

Puerto Refugio, Isla Ángel de la Guarda (Islas de la Cintura), 

Gulf of California, Mexico.

Remarks. Dawson (1966b: 66) noted that cystocarps on Polyneurella hancockii from Isla San Lorenzo were 

“mainly in submarginal regions,” whereas they were scattered 

on the blade from Canal de Infiernillo (JN-4727; Figure 112B).

Polyneurella hancockii var. rhizoidea E. Y. Dawson

Polyneurella hancockii var. rhizoidea E. Y. Dawson, 1962a:86, pl. 37: fig. 2; 

González-González et al., 1996:252; Wynne, 2014:149.

Blades similar to. P. hancockii var. hancockii; differing primarily in having a prostrate, adherent basal structure and blade 

margins that are somewhat proliferous with groups of branched, 

spreading rhizoidal outgrowths.

Tetrasporangial sori very small, mostly less than 300 μm in 

diameter. Cystocarps and spermatangia unknown.

Habitat. On rocks; subtidal, dredged from 18.3–

36.6 m depths.

Distribution. Gulf of California: Bahía de San Lucas.

Type Locality. Dredged from 20 fathoms (about 

36.6 m) depth, Bahía de San Lucas, Baja California Sur, Gulf of 

California, Mexico.

Remarks. Polyneurella hancockii var. rhizoidea

is known only from the type specimens. More collections are 

needed to evaluate its taxonomic status.

Schizoseris Kylin

Schizoseris Kylin, 1924:67.

Blades erect, simple, lobed, irregularly divided or laciniate, 

arising from a stipe. Blades are branched in 1 plane. Macroscopic veins are present, basal and simple, or subdichotomously 

branched and extending through most of blade but are not percurrent and do not reach the thallus margins. Macroscopic veins 

increase in thickness with age; microscopic veins are absent. 

Growth is diffuse, from marginal and intercalary meristems. 

Thalli are initially and primarily monostromatic and may become polystromatic in basal areas, stipes, and the macroscopic 

veins. In surface view, blades are an irregular mixture of cells of 

various shapes and sizes, a result of intercalary cell divisions.

Tetrasporangial sori are small and discrete or can become 

confluent, forming large sori. Tetrasporangia are tetrahedrally 

divided, borne in 2 layers, primarily originating from subsurface 

cortical cells. Gametophytes are usually dioecious. Procarps are 

formed singly, with 2 sterile groups (each composed of 1–2 cells), 

off a 4-celled, strongly curved, carpogonial branch. Cystocarps 

are borne near blade margins, with extensive branched fusion 

cell, pericarp 4–6 cell layers thick, with an ostiole. Carposporangia are borne in simple or branched chains. Spermatangial sori 

are produced in both monostromatic and polystromatic areas of 

the blade, with spermatangia cut off from cortical cell initials on 

both sides of the blade.

One species of Schizoseris is known in the northern Gulf of 

California.

FIGURE 112. (Opposite) Polyneurella hancockii: A. Habit, small group of blades with barely visible longitudinal veins, and tetrasporangial 

sori (JN-4720, US Alg. Coll.-217356). B. Cystocarps scattered over blade, veins discernable to some extent (JN-4727, US Alg. Coll.-217357). 

C. Apex of blade with an apical cell (JN-4725, US Alg. Coll. microscope slide 5283). D. Slender longitudinal veins in blade (US Alg. Coll. microscope slide 5285).
NUMBER 96 • 231
232 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Schizoseris pygmaea E. Y. Dawson

FIGURE 113

Schizoseris pygmaea E. Y. Dawson, 1950b:157, figs. 16, 17; 1959a:29; 

1961b:445; 1962a:80, pl. 35: figs. 3, 4; 1966a:28; Dawson and 

Neushul, 1966:183 [with a query]; Stewart and Stewart, 1984:146; 

González-González et al., 1996:252; L. Aguilar-Rosas et al., 

2000:131; CONANP, 2002:138; Pacheco-Ruíz and ZertucheGonzález, 2002:468.

Myriogramme bombayensis sensu Pacheco-Ruíz et al., 2008:212 [non 

Myriogramme bombayensis Børgesen, 1931:23, which is now Schizoseris bombayensis (Børgesen) S.-M. Lin, 2002:39; =Schizoseris bombayensis (Børgesen) Womersley, 2003:112, nom. illeg.)].

Blades erect, membranous, small, up to 2(–3) cm tall and 

2.5–3.5 mm wide, with short, terete, stipe-like portions at base of 

blades. Stipes thickness extends into blade as conspicuous broad 

midvein, to about 200 μm wide, and divides subdichotomously; 

midveins gradually tapering, not extending to blade tips or margins. Vegetative blades monostromatic apart from polystromatic 

midveins and stipes. New blades can develop along stipe or on 

short “secondary” stipes from the macroscopic veins in basal 

portion of a blade. Blades orangish brown, simple or lobed to 

sparsely irregularly subdichotomously divided. Tips of blades 

rounded, margins entire, smooth to ruffled. Tufts of rhizoids can 

grow out from blade margins for secondary attachment. In surface view, cells of blade of various shapes, 6.0–12 μm in diameter.

Tetrasporangial sori typically a single broadly rounded 

patch in middle and distal portions of a blade, covering most of 

the blade’s width.

Habitat. On rock and epizoic on sponges; low intertidal to shallow subtidal, 0.75–2.0 m depths.

Distribution. Gulf of California: Playa Tucson 

and Playa Las Conches (Playa Estación), Puerto Peñasco to 

Puertecitos; Isla la Ventana (Bahía de Los Ángeles); Isla Partida 

Norte; Isla San Pedro Nolasco; Bahía Agua Verde to Isla Cholla 

(off northern end of Isla Carmén). Eastern Pacific: California 

Channel Islands to Punta Eugenia (“San Eugenio”); Bahía Sebastián Vizcaíno, Baja California Sur; Isla Guadalupe. Western 

Pacific: Korea (Y.-P. Lee and Kang, 2001).

FIGURE 113. Schizoseris pygmaea: A. Blade with subdichotomously branching midvein (JN-3823, US Alg. Coll. microscope slide 5282). B. 

Habit (JN-3823, US Alg. Coll.-160889). C. Close-up of polystromatic midrib region and monostromatic blade, with cells of various sizes and 

shapes, the result of intercalary cell divisions (JN-3902, US Alg. Coll. microscope slide 5286).
NUMBER 96 • 233

Type Locality. Intertidal rocks; Isla Partida Norte, 

Islas de la Cintura, Gulf of California, Mexico.

Remarks. Schizoseris pygmaea is apparently rare but 

occurs sparsely at scattered localities in the Gulf of California. 

Noting a lack of female material, Dawson (1959a) commented 

that on the basis of vegetative morphology it was similar to 

the Japanese Myriogramme subdichotoma Segawa (1941; now 

Schizoseris subdichotoma (Sewaga) Yamada, 1944; =Schizoseris 

minima Kaneko et Masaki, 1973), but Dawson (1962a) later observed that S. pygmaea differed in its less extensive dichotomy 

and its large, usually solitary, tetrasporangial sori. Following 

Segawa (1941), Dawson (1959a) also noted its resemblance to 

Myriogramme bombayensis Børgesen (1931), and later Abbott 

(1999) tentatively placed S. pygmaea in synonymy with M. bombayensis (see also Millar and Kraft, 1993; Wynne, 2014). Lin 

(2002) and Womersley (2003) thought features of M. bombayensis better fit the genus Schizoseris with the earliest combination 

being S. bombayensis (Børgesen) S.-M. Lin.

Although observing similarities to the Gulf of California 

Schizoseris pygmaea, Dawson and Neushul (1966) tentatively 

referred their Anacapa Island (California Channel Islands) 

specimens to S. pygmaea but noted they were probably an undescribed species. Until reproductive gametophytes are found and 

described for Gulf of California S. pygmaea (especially from the 

type locality), and it can be tested by comparative morphology 

and molecular analyses with other taxa, including S. bombayensis, the Gulf specimens are retained as Schizoseris pygmaea.

Sorella Hollenberg

Sorella Hollenberg, 1943:577.

Algae erect, small membranous fronds that are uniformly narrow and much branched (up to 4–8 orders) from the blade margins. 

Some of lowermost basal branches are more or less prostrate, attaching the frond by hapterous bundles of rhizoids produced adventitiously near blade margins. Axes and branches are slender, generally 

of similar width and with smooth margins, monostromatic, except 

in the inconspicuous midrib regions, and lack lateral veins. Apical 

cells are prominent, and intercalary divisions occur in primary cell 

row; secondary and tertiary cell rows indistinct.

Tetrasporangial sori are oval and typically singular in the center of blades, most developing near the apices. Cystocarps are found 

on 1 side of the midrib, with an ostiole. Spermatangia are in oval to 

oblong sori, single or in pairs toward the distal region of branches.

Two species of Sorella are reported in the northern Gulf of 

California.

KEY TO THE SPECIES OF SORELLA IN THE NORTHERN GULF OF CALIFORNIA

1a. Narrow fronds, 0.2–0.5(–0.6) mm wide; repeatedly dichotomously to subdichotomously branched, up to 8 orders, with 

comparatively long intervals between branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . S. delicatula

1b. Fronds generally broader, mostly (0.5–)0.8–2.0 mm wide; pinnately branched, up to 4 orders . . . . . . . . . . . . S. pinnata

Sorella delicatula (N. L. Gardner) Hollenberg

Erythroglossum delicatulum N. L. Gardner, 1926:208, pl. 18.

Sorella delicatula (N. L. Gardner) Hollenberg, 1943:577; Dawson, 

1961b:446; 1962a:83, pl. 34: fig. 2; Dawson and Neushul, 1966:183; 

Abbott and Hollenberg, 1976:648, fig. 591; Stewart and Stewart, 

1984:146; Stewart, 1991:149, fig. 14; González-González et al., 

1996:270; Pacheco-Ruíz et al., 2008:212; Wynne, 2014:212, fig. 102.

Sorella delicatula var. californica Hollenberg, 1943:577, figs. 13, 14; Dawson, 1961b:446; Stewart, 1977:5–15, fig. 1A–C,F; Pacheco-Ruíz and 

Zertuche-González, 2002:468.

Erythroglossum divaricatum Setchell et N. L. Gardner in Gardner, 1926:207, 

pl. 17: fig. 2; Smith, 1944:340, pl. 87: fig. 7.

Sorella divaricata (Setchell et N. L. Gardner) Hollenberg, 1943:578; Dawson, 

1961b:446; Hollenberg and Abbott, 1966:105.

Erythroglossum californicum sensu Dawson, 1962a:93 [in part; Isla Magdalena specimens only; see Abbott and Hollenberg, 1976:648; non Erythroglossum californicum (J. Agardh) J. Agardh, 1898:176; basionym:

Delesseria californica J. Agardh, 1885:69].

Blades mostly 1–2(–10) cm tall; of delicate, narrow, ribbonlike axes and branches, 200–500(–600) μm wide, mostly with 

entire margins; dichotomous to subdichotomously branched, up 

to 8 orders; relatively long intervals between branches. Blades 

monostromatic, with an inconspicuous, polystromatic midrib 

(distinct with magnification).

Tetrasporangia in more or less oval sori, 200–400 μm 

wide; sori solitary in upper portion of branches toward the tips. 

Cystocarps 400–450 μm in diameter (nearly the entire width 

of the blade). Spermatangia in irregular oval sori near branch 

apices.

Habitat. On rocks or in tidal channels; also reported 

to be occasionally epiphytic on other red algae or epizoic on 

worm tubes or sponges (Stewart, 1991); low intertidal to shallow subtidal, down to 20 m depths.

Distribution. Gulf of California: Isla Coronado 

(Isla Smith), Bahía de Los Ángeles. Eastern Pacific: Santa Cruz 

to San Diego, California; California Channel Islands; Isla Coronado Norte (Islas Los Coronados), and Isla Guadalupe off 

northern Baja California; Isla Magdalena (NNW side of Bahía 

Magdalena), Baja California Sur. Western Pacific: Japan.

Type Locality. Cast ashore; San Pedro, Los Angeles County, southern California, USA.

Sorella pinnata Hollenberg

FIGURE 114

Sorella pinnata Hollenberg, 1943:578, figs. 15, 16; Dawson, 1944a:321, 

pl. 47: figs. 3, 4; 1951:53; 1961b:446; 1962a:84, pl. 38: fig. 1; pl. 

40: fig. 6; Dawson and Neushul, 1966:183; Abbott and Hollenberg, 

1976:650, fig. 592; Stewart, 1977:5–15, fig. 1D, E, G; 1991:150, fig. 
234 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

14; González-González et al., 1996:270; Pacheco-Ruíz et al., 2008:212; 

Wynne, 2014:213.

Blades small, semierect to partly repent, mostly 1–2(–7) 

cm tall and (0.5–)0.8–2.0(–3.5) mm wide, peach to rose pink 

in color; of thin, lanceolate blades, pinnately branched from 

margins, up to 3(–4) orders. Blades monostromatic, except for 

basal portions and indistinct midribs (distinct under magnification); attached by filamentous rhizoids that develop in groups 

along blade margin where in contact with substrate. Growth 

from an apical cell, primary cell row with intercalary cell divisions. Blades with smooth margins, except for protruding apical 

cells (branch initials), giving a widely spaced, dentate appearance 

FIGURE 114. Sorella pinnata: A. Branching habit, median tetrasporangial sori mostly in distal regions. B. Median tetrasporangial sori. C. Tetrasporangial sorus covering distal and central portion of blade (A–C, JN-4749, US Alg. Coll. microscope slide 4642). D. Portion of blade showing 

midrib of main axis and developing midribs of branches (JN-5154, US Alg. Coll. microscope slide 4643). E. Upper portion of blade showing 

monostromatic blade with thickened midrib region (JN-3131, US Alg. Coll. microscope slide 4645). F. Upper portion of blade with conspicuous 

apical cells and developing midrib (JN-5154, US Alg. Coll. microscope slide 4643).
NUMBER 96 • 235

under a microscope (Figure 114B, E). Blades usually tapering to 

acute tip with apical cell.

Tetrasporangial sori oval, 300–600(–800) μm long, mostly 

200–300 μm wide; single in middle of blades near apices; tetrasporangia about 45–50 μm in diameter. Cystocarps 400–500 μm 

in diameter, with an ostiole; on one side of midrib. Spermatangia 

in oblong sori; mostly in pairs, one to each side of midrib region; 

often several pairs of sori on one branch.

Habitat. On rocks; shallow subtidal, down to 20 m 

depths.

Distribution. Gulf of California: Rocas Consag; 

Puerto Libertad to Guaymas; Puerto Refugio, Isla Ángel de la 

Guarda. Eastern Pacific: Laguna Beach to Cortez Bank, California Channel Islands (about 188 km west of San Diego, 82 

km SW of San Clemente Island), southern California; Islas San 

Benito and Isla Cedros, Baja California.

Type Locality. On intertidal rocks; Laguna Beach, 

Orange County, southern California, USA.

Taenioma J. Agardh

Taenioma J. Agardh, 1863:1256.

Thalli are small, often growing in turf-like mats, with 

erect and prostrate portions and determinate and indeterminate 

branches. Thalli uniaxial in structure with growth of branches 

from a single apical cell, branching exogenous at branch apices, 

often endogenous or adventitious below. Primary prostrate axes 

are terete (to compressed), ecorticate, rhizomatous, and spreading, attached to substrate by uniseriate rhizoids. Prostrate axes 

give rise to erect and ascending tufted branch systems composed 

of secondary axes with determinate flattened laterals. These secondary axes are terete to compressed and bear both additional 

axes and erect, alternately or radially arranged determinate 

flattened laterals. The determinate flattened laterals are monostromatic blades, except for their polystromatic midrib (3 cells 

thick). Midrib with axial cells each surrounded by 4 pericentral cells. The lateral pericentral cells of determinate blades each 

issue 2 flanking cells, which remain undivided or in some species 

divide to form 2–3 (or more) cell chains (monostromatic). Apices of determinate blades nearing maturity typically terminate in 

0–5 (or more) persistent, unpigmented, unbranched multicellular 

“hairs” (filaments), each with a meristem at its base.

Tetrasporangia are tetrahedrally divided and produced in a 

single layer, 2 per segment, forming 2 longitudinal rows along sides 

of the midrib of determinate blades. Tetrasporangia are issued 1 per 

fertile lateral pericentral cell, before the rudimentary cover cells are 

formed. Gametophytes are usually dioecious, but fertile specimens 

are apparently rarely encountered. Procarps and cystocarps are 

borne on indeterminate axes. Procarps composed of a 4-celled carpogonial branch and 2 sterile-cell groups. Cystocarps have a basal 

fusion cell and carposporangia in short chains enclosed in an urceolate pericarp with ostiole. Spermatangia are borne in sori on both 

surfaces of determinate blades between midrib and blade margin.

One species of Taenioma is known in the northern Gulf of 

California.

Taenioma perpusillum (J. Agardh) J. Agardh

FIGURE 115

Polysiphonia perpusilla J. Agardh, 1847:16.

Taenioma perpusillum (J. Agardh) J. Agardh, 1863:1257; Okamura, 

1930:26, pl. 264: figs. 17–19, pl. 265: figs. 5–9; Dawson, 1944a:324; 

Tseng, 1944:223, pl. 25: figs. 1–6; Papenfuss, 1944b:193, pl. 23: figs. 

1–4, pl. 24: figs. 5–16; Dawson, 1962a:82, pl. 37: fig. 1, pl. 47: fig. 3; Papenfuss, 1964a:159, figs. 1–10; Huerta-Múzquiz and Tirado-Lizárraga, 

1970:129; Santelices and Abbott, 1987:9; Ramírez and Santelices, 

1991:358; Mateo-Cid and Mendoza-González, 1992:22; ServiereZaragoza et al., 1993a:484; González-González et al., 1996:326, 408; 

Yoshida, 1998:997; Abbott, 1999:348 [in part; not including Taenioma 

dotyi Hollenberg, 1967:1202, fig. 101C]; CONANP, 2002:138; Zheng 

et al., 2001:134, fig. 81(1–6) ; Abbott et al., 2002:314, figs. 28–29; 

Pacheco-Ruíz et al., 2008:212; Fernández-García et al., 2011:65; 

Wynne, 2014:74, fig. 35.

Thalli short, to 3 mm high, with creeping, terete indeterminate axes, 65–90(–200) μm in diameter, and erect and ascending 

branches. Prostrate axes polysiphonous, with 4 pericentral cells, 

attached to the substrate by long nonseptate rhizoids issued from 

ventral pericentral cells. Indeterminate prostrate axes bear terete 

secondary axes that bear both additional indeterminate axes and 

are abundantly alternately branched with determinate flat bladelike laterals. The determinate branches start off terete for several 

segments, then flatten above as lateral pericentral cells each give 

rise to 2 flanking cells, each about half the length of a pericentral 

cell, forming the monostromatic “wings” of the blade. Determinate blades unbranched, composed of a midrib (three cells thick, 

the axial filament with 2 transverse pericentral cells above and 

below), lateral pericentrals, and flanking cells along blade margins. Determinate blades up to 1 mm long and usually 5 cells 

across (to 100 μm wide). Up to 3 persistent unpigmented, uniseriate filaments (“hairs”) develop terminally on most determinate 

blades near maturity; these apical filaments each have a basal 

meristem with elongated cells above.

Tetrasporangia in a single layer, in consecutive segments 

forming 2 longitudinal rows of tetrasporangia, on both sides of 

the midrib of determinate blades. A single tetrasporangium arises 

from a fertile lateral pericentral cell, and later 2 small rudimentary cover cells are cut off. Gametophytes unknown in Gulf material (apparently rarely encountered elsewhere). Gametophytes 

reported elsewhere usually dioecious (Papenfuss, 1964a). Procarps usually solitary on erect terete secondary axes (Papenfuss, 

1964a; Abbott, 1999). Cystocarps urceolate and ostiolate. Spermatangia borne on determinate blades. 

Habitat. On rocks, entangled or epiphytic on other 

algae, or in algal turfs; mid to low intertidal.

Distribution. Gulf of California: Bahía de San Luis 

Gonzága; Isla Tiburón to Topolobampo; Sinaloa to Jalisco. Eastern Pacific: Golfo de Tehuantepec, Oaxaca; El Salvador; Panama; 

Rapa Nui (Easter Island; Isla de Pascua). Central Pacific: Hawaiian Islands. Western Pacific: China; Korea; Japan; Vietnam.

Type Locality. San Agustín (San Augustin), “presumably in the Isthmus of Tehuantepec along the coast of Oaxaca” (Dawson, 1962a:83), Pacific Mexico.
236 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Remarks. Taenioma perpusillum is reported to be 

widespread in tropical and subtropical seas and into temperate 

regions. Apparently, T. perpusillum is rare or uncommon in the 

northern Gulf; probably because of its small size and usual entanglement with other algae, it may be easily overlooked. C. F. 

Puttock (National Museum of Natural History, Department of 

Botany, personal communication) observed there is likely more 

than one species included within the T. perpusillum complex.

Sarcomeniaceae

Sarcomeniaceae Womersley, 2003:148–150.

Algae are erect, cylindrical or compressed, branched thalli. 

The apical cell is prominent, with axial filament cells cutting off 

four pericentral cells, two transverse pericentral cells and two 

slightly larger lateral pericentral cells. The lateral pericentral 

cells each cut off two flanking cells that are about half the length 

of a pericentral cell. The flanking cells produce additional rows 

of cells in some genera. Intercalary divisions are absent in primary cell rows. Branching is endogenous.

Tetrasporangia are cut off from the lateral pericentral cells 

in two longitudinal rows, forming in a single layer, with postsporangial cover cells. Gametophytes are dioecious. Procarps are 

borne on the transverse pericentral cells. The carpogonial branch 

is four-celled with two groups of sterile cells. Carposporophytes 

have a basal fusion cell and branched gonimoblasts that bear 

clavate carposporangia terminally. Cystocarps protruding from 

blade; ovoid to urceolate, with post-fertilization pericarp and ostiole. Spermatangia are borne in sori on surface of blades.

The Sarcomeniaceae is represented by one genus in the 

northern Gulf of California.

Platysiphonia Børgesen

Platysiphonia Børgesen, 1931:28.

Thalli of erect, branched, blades and prostrate portions that 

are morphologically similar in structure and width. Blades are delicate, narrow, flattened, and monostromatic, apart from the midrib, 

and taper to a single apical cell at apices. Intercalary cell divisions 

absent. Midrib is percurrent with 4 pericentral cells. Endogenous 

branches usually arise from the midline of a parent blade. Lateral pericentral cells issue flanking cells, and in some species these 

produce flanking cell derivatives that increase the number of cells 

and width of the blades. Blades are ecorticate in some species but 

heavily corticated in others. All vegetative axes are potentially indeterminate. Monosiphonous filaments are absent. 

FIGURE 115. Taenioma perpusillum: A. Habit showing creeping indeterminate terete axes giving rise to determinate flat blades and additional 

indeterminate axes. B, C. Upper portions of mature determinate blades with 2–3 monosiphonous “hairs” at their tips (A, C, EYD-10891, US 

Alg. Coll. microscope slide 569; B. EYD-10908, US Alg. Coll. microscope slide 570).
NUMBER 96 • 237

Tetrasporangia are produced in stichidium-like ultimate 

blades, in a single layer, and paired, each fertile lateral pericentral cell cutting off a tetrasporangium, subsequently forming 2 

longitudinal rows, with sterile cells lining blade margins. Gametophytes are dioecious. Procarps and cystocarps are restricted to 

midline of fertile blades, carposporangia terminal. Spermatangial 

blades have sterile bases and tips and sterile transverse pericentral cells and cells along margins. Spermatangia formed mostly 

from lateral pericentral cells.

There is one species of Platysiphonia known in the northern 

Gulf of California.

Platysiphonia decumbens M. J. Wynne

FIGURE 116

Platysiphonia decumbens M. J. Wynne, 1969:190, figs. 1–36; Abbott and 

Hollenberg, 1976:644, fig. 585; Scagel et al., 1989:225; Stewart, 

1991:148, fig. 13 [left illustration]; Wynne, 2014:240, figs. 116b–c 

(type collection).

Platysiphonia clevelandii sensu Dawson, 1966b:66; González-González et 

al., 1996:248 [in part]; Pacheco-Ruíz et al., 2008:212 [non Platysiphonia clevelandii (Farlow) Papenfuss, 1944a:206; basionym: Taenioma 

clevelandii Farlow, 1877:236].

Thalli small, usually less than 2 cm high, with both erect 

and prostrate portions. Blades slender, ribbon-like, usually to 7 

cells wide (200–400 μm wide). Blades taper to an acute apex, 

and growth is from a single apical cell, midribs with central axial 

cell surrounded by 4 pericentral cells, the midline is 3 cells thick 

(axial cell and a transverse pericentral cell above and below), 

blades monostromatic away from the midline. Blades flat, ecorticate, the lateral pericentral cells cut off flanking cells, each of 

which cuts off flanking cell derivatives that form the blade’s 

margin and are laterally elongated. Attachment rhizoids develop 

from several contiguous marginal cells, and abutting flanking 

cells also sometimes involved in producing a holdfast. Branches 

originating at irregular intervals from midrib of parent blade, 

only from the adaxial surface. Branch blades more slender at 

attachment point as the lowest several segments may be missing 

flanking cells and flanking cell derivatives. Erect branches may 

later become prostrate by developing marginal rhizoids and attaching to substrate or host.

Reproduction not seen in Gulf material. Tetrasporangia cruciately divided, borne in single cell layer in short, stichidium-like 

ultimate blades. Each lateral pericentral cell producing a single 

tetrasporangium with a cover cell; 2 in each segment, resulting in 

FIGURE 116. Platysiphonia decumbens: A. Surface view of blade apex of specimen from the northern Gulf of California (JN-5324, US Alg. 

Coll. microscope slide 5290). B, C. Blades 7 cells wide, new blades originating from midrib of parent blade (specimen from the southern Gulf ; 

EYD-26116, US Alg. Coll. microscope slide 794).
238 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

2 paired longitudinal rows, bordered by sterile cells along blade 

edges (after Wynne, 1969). 

Habitat. Often epiphytic or entangled on larger 

algae or growing on hard substratum; low intertidal to subtidal, 

8–16 m depths (Dawson, 1966b, as “P. clevelandii”).

Distribution. Gulf of California: Isla Ángel de la 

Guarda; Isla Las Ánimas (Isla San Lorenzo del Norte). Eastern 

Pacific: southern Alaska to northern Baja California.

Type Locality. West Beach, Whidbey (“Whidby”) 

Island, Island County, Puget Sound, Washington, USA.

Remarks. Platysiphonia decumbens was described 

from the cool, temperate waters of Whidbey Island, Washington. It was surprising to find it in the warmer waters of the 

northern Gulf (Norris, 2010). In Pacific Mexico, P. decumbens 

from Isla Guadalupe (Stewart and Stewart, 1984) and northern 

Baja California (Dawson, 1962a) can also occur with P. clevelandii (Farlow) Papenfuss (1944a) and P. parva P. C. Silva et 

Cleary (1954).

Rhodomelaceae

Rhodomelaceae Areschoug, 1847:260.

Thalli are usually erect or partially to entirely prostrate and 

may be terete, compressed, or flat and sparsely to abundantly 

branched. All species are polysiphonous and either ecorticate or 

faintly to fully corticated. Growth is uniaxial from large apical 

cells. Two or more pericentral cells are cut off in an alternating sequence around each central axial cell. Erect species have 

branches of similar structure or indeterminate branches and determinate branches of limited growth with different structures. 

Apices are radially or dorsiventrally organized. Monosiphonous 

trichoblasts, commonly present in certain genera, are branched 

or unbranched and colorless in most genera, but in a few they 

can be pigmented.

Tetrasporangia are generally tetrahedrally divided and are 

usually developed from pericentral cells or, in a few, from the 

outer cortical cells. Tetrasporangia borne in specialized branchlets, stichidia, or within main axes or lateral branches, and may 

be (1) one per segment, sometimes in a series in a straight row or 

spirally arranged; (2) two per segment and distichously or decussately arranged; or (3) 4–6 per segment when verticillate in arrangement. Gametophytes are usually dioecious. Gametangia in 

many are developed from or usually associated with the trichoblasts. Procarps borne on lower cells of trichoblast or directly on 

thallus branches. Cystocarps are prominent, with carposporangia in short chains and an ostiolate pericarp. Spermatangia may 

be borne in modified trichoblasts or replace a whole trichoblast; 

in discoid plate-like structures with sterile marginal cells, usually near apices; on special spermatangial branchlets; or less frequently on ordinary axes and branches.

Fifteen genera of the family Rhodomelaceae are represented 

in the northern Gulf of California.

KEY TO THE GENERA OF RHODOMELACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Algae flattened, mostly prostrate, lobed blades; composed of polysiphonous branches congenitally fused to adjacent 

branches to form blades . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Amplisiphonia

1b. Algae not a membranous blade; thalli terete, compressed, or flattened; erect or partly prostrate axes with at least some 

erect branches; polysiphonous axes not congenitally fused (or only 1 to few basal segments of laterals fused) . . . . . . . 2

2a. Thallus polysiphonous, not corticated throughout; segments of pericentral cells easily seen below the apices . . . . . . . . 3

2b. Thallus either polysiphonous and partly to entirely corticated, obscuring segments of pericentral cells below apex; or 

terete to flattened with a pseudoparenchymatous medulla and cortex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3a. Pericentral cells divided transversely to form 2 tiers of cells within the length of a single axial filament cell; growing in 

brackish water . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Bostrychia

3b. Pericentral cells not transversely divided, same length as axial filament cell they surround; growing in marine waters . . . 4

4a. Thallus with pigmented trichoblasts (ultimate monosiphonous branchlets) . . . . . . . . . . . . . . . . . . . . . . . . . . . . Veleroa

4b. Thallus without trichoblasts (ultimate monosiphonous branchlets), or if present, trichoblasts unpigmented (colorless) . . . . 5

5a. Thalli radially or spirally arranged . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5b. Thalli either bilaterally arranged (at least in older portions) or dorsiventrally arranged . . . . . . . . . . . . . . . . . . . . . . . . 7

6a. Trichoblasts rare or absent; rhizoids (nonseptate) remaining open in connection with bearing pericentral cell; spermatangial branches arising from lateral branch initials without trichoblasts; tetrasporangia arranged in straight series; carpogonial branch 4-celled . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Polysiphonia

6b. Trichoblasts abundant; rhizoids separated from bearing pericentral cells by a cell wall (pit-connected); spermatangial 

branches on a branch of a trichoblast; tetrasporangia in a spiral series; carpogonial branch 3-celled . . . . . Neosiphonia

7a. Determinate and indeterminate laterals in regular defined sequence; axes with 3 simple determinate laterals between each 

indeterminate compound lateral; primary indeterminate axis prostrate . . . . . . . . . . . . . . . . . . . . . . . . . . Herposiphonia

7b. Determinate and indeterminate laterals not arranged in regular defined sequence; primary indeterminate axis not 

prostrate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

8a. Branch segments at base of lateral branches with little or no fusion (coalescing) with the bearing axis . . . . . Tayloriella

8b. Branch segments at base of lateral branches fused (coalescing) with bearing axis for 1 to a few segments . . . . . . . . . . 9
NUMBER 96 • 239

9a. Distichous branching; determinate laterals alternate, with 2–4 axial segments between them; trichoblasts absent on nonreproductive thalli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pterosiphonia

9b. Determinate laterals initially multifariously arranged at tips of erect axes, then becoming more distichous below; trichoblasts few to common on nonreproductive thalli . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pterosiphoniella

10a. Axes and branches, usually densely surrounded by short, stiff, simple corticated branchlets . . . . . . . . . . . . . . . Digenea

10b. Axes not as above; without numerous, dense stiff lateral branchlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

11a. Spermatangial structure a flat, oval disc, with a margin of sterile cells; borne on trichoblast; in cross section of axes, 5 

pericentral cells and central axial cell discernible in most species . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chondria

11b. Spermatangial structure not discoid or plate-like; in cross section of axes, central axial cell and pericentral cells only 

clearly discernible near apices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

12a. Thalli of species in Gulf compressed to flattened, tetrasporangia develop from random epidermal cells; filament-type 

spermatangial development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Osmundea

12b. Thalli terete to only slightly compressed, tetrasporangia produced from specific pericentral cells; trichoblast-type spermatangial development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

13a. Vegetative segments with axial cell bearing 2 pericentral cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 

13b. Vegetative segments with axial cell bearing 4 pericentral cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Laurencia

14a. Tetrasporangial axial segments in first and second pericentral cells sterile, and additional fertile pericentral cells issued to 

produce tetrasporangia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Chondrophycus

14b. Outer cortical cells longitudinally elongated, and in a distinctive palisade-like arrangement in transection; in tetrasporangial axial segments only first pericentral cell is sterile, second is fertile with an additional third fertile pericentral cell to 

produce tetrasporangia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Palisada

Rhodomelaceae tribus Bostrychieae

Rhodomelaceae tribus Bostrychieae Falkenberg, 1901:504.

Remarks. Phylogenetic analyses of Zuccarello and 

West (2006: fig. 2) found the Baja California Sur Bostrychia 

radicans grouped with others within the “Cladohapteron clade” 

of the subfamily Bostrychioideae. Further, their analyses did not 

support continued recognition of two genera within the tribe, 

with Stictosiphonia J. D. Hooker et Harvey (in Harvey and 

Hooker, 1847:483; King and Puttock, 1989) being considered 

congeneric with Bostrychia.

The tribe is represented by one genus, Bostrychia, in the 

Gulf of California. It usually occurs in brackish water habitats 

with some freshwater influences.

Bostrychia Montagne

Bostrychia Montagne, 1842b:39; Montagne, 1842c:600.

Stictosiphonia J. D. Hooker et Harvey in Harvey and Hooker, 1847:483; 

Zuccarello and West, 2006:31.

Algae are dorsiventrally organized, with narrow terete to 

compressed polysiphonous axes and branches that usually form 

dense turfs, clumps, patches, or spreading mats. They are often 

epiphytic on mangroves or other aquatic vegetation, entangled 

with other algae, or may grow on hard or soft substrata. Thalli 

are composed of prostrate and erect indeterminate polysiphonous 

axes and branches of 4–10 pericentral cells that are uncorticated 

or corticated by up to 5 layers of cortical cells. Each pericentral cell transversely divides into 2–5 tiers, with the basal cell pit 

connected to the axial cell. Prostrate axes give rise to creeping 

or erect lateral branches alternately to irregularly arranged and 

attached by bundles of rhizoids developed from pericentral or 

cortical cells (peripherohaptera), or by terminal rhizoidal haptera on specialized branches (cladohaptera). Branches are simple 

or branched up to 3(–4) orders. Trichoblasts are absent. Ultimate 

branches may be entirely or partly monosiphonous.

Tetrasporangia tetrahedrally divided, borne 2–6 per segment 

in polysiphonous branches or in stichidia up to 25 segments in 

length. Gametophytes are usually dioecious, but some may be 

monoecious. Procarps develop in a series of 1–4 per segment on 

polysiphonous determinate branches. Each procarp is a single 

sterile group and a 3– to 4–celled carpogonial branch. Carposporophytes are sessile and usually borne 1–2 per branch, with a 

short, branched gonimoblast that bears terminal carposporangia 

within ovoid to subspherical pericarp. Spermatangia are superficial on determinate laterals that lack or may have sterile tips.

Remarks. West et al. (2013) noted that the taxonomy 

and molecular phylogeny of Bostrychia, while well studied, is 

not yet completely resolved. One species, Bostrychia moritziana

(Sonder ex Kützing) J. Agardh (1863; including B. radicans f. moniliforme E. Post, 1936, as a synonym), has been reported in 

the southern Gulf of California from Bahía de La Paz (HuertaMúzquiz and Mendoza-González, 1985), from Nayarit and 

Jalisco (Dawson, 1963b; Serviere-Zaragoza et al., 1993a), and in 

Pacific Mexico from Chiapas (Dreckmann et al., 2006).

One species of Bostrychia is known in the northern Gulf of 

California.

Bostrychia radicans (Montagne) Montagne

Rhodomela radicans Montagne, 1840:198, pl. 5: fig. 3.

Bostrychia radicans (Montagne) Montagne, 1842c:661; Kützing, 1847:4; 

Montagne, 1850:286; Howe, 1914:145; Post, 1936:13; Tseng, 

1943:173, pl. 2: figs. 6, 7; Dawson, 1944a:336, pl. 49: figs. 3, 4; Taylor, 

1945:306; Post, 1955:354, 377, pl. 15: fig. 2; Post, 1957:85; Dawson, 
240 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

1957c:23; 1961b:451; 1963b:419, pl. 136: fig. 3; Dawson et al., 

1964:84, pl. 34: fig. D; Tanaka and Chihara, 1984:172, fig. 2; HuertaMúzquiz and Mendoza-González, 1985:54; Tanaka, 1991:6, figs. 1–14; 

Ramírez and Santelices, 1991:359; Serviere-Zaragoza et al., 1993a:483; 

Pedroche et al., 1995:115; González-González et al., 1996:303, 385; 

Yoshida, 1998:1011, fig. 3-102M–O; Dreckmann et al., 2006:155; Zuccarello and West, 2006:26, tbl. 1, fig. 3; G.-H. Kim et al., 2008:1519; 

Bernecker, 2009:CD-Rom p. 66; Pérez-Estrada et al., 2012:190.

Bostrychia rivularis Harvey, 1853:57, pl. 14D; Santelices and Abbott, 

1987:219; Ramírez and Santelices, 1991:360.

Algae forming dense mats, reddish brown, up to 1.5 cm tall; 

thallus distichously branched (somewhat feather-like appearance), with incurved apices; growing from creeping prostrate 

axes, 150–200 μm in diameter; attached by small trunk-like 

holdfasts and secondary basal branches with rhizoid-like attachments. Erect branches, 75–125 μm in diameter, uncorticated, 

polysiphonous, of 4–8 pericentral cells; each pericentral cell 

transversely divided once into 2 tiers.

Tetrasporangia in whorled series within mid to upper portions of swollen, ultimate branchlets. Gametophytes not known 

in the northern Gulf.

Habitat. On mangroves (prop roots of Rhizophora 

mangle Linnaeus and pneumatophores of Avicennia germinans

Linnaeus), other aquatic vegetation or sometimes on mud, in 

fresh to brackish waters of river mouths, esteros, and lagoons; 

intertidal to shallow water.

Distribution. Gulf of California: Río Mayo, on 

north side of Yavaros (about 26 km southwest of Huatabampo, 

Sonora); Estero Coyote, Bahía San Ignacio (Baja California Sur); 

Bahía de La Paz; Nayarit to Jalisco. Eastern Pacific: Chiapas; Guatemala to El Salvador; Costa Rica to Panama; Colombia to Chile; 

Galápagos Islands. Western Pacific: Japan; Korea; Vietnam.

Type Locality. Probably an estuary of the Cayenne 

River; near Cayenne, French Guiana.

Remarks. Bostrychia radicans is widely reported in 

warm temperate to tropical regions. Zuccarello and West (2003) 

found several cryptic species within a Bostrychia radicans–

B. moritziana species complex (Zuccarello et al., 1999), and 

more recently, West et al. (2013) recognized this complex to be 

of seven molecular lineages that were not reproductively intercompatible. Although there was considerable genetic divergence, 

taxonomic resolution of the species lineages remains problematic 

(e.g., Zuccarello and West, 2006; West et al., 2013). G.-H. Kim 

et al. (2008) found that using proteomic analyses of species of 

Bostrychia made it possible to discern genetic differentiation and 

may be a useful technique for taxonomic studies.

Rhodomelaceae tribus Chondrieae

Rhodomelaceae tribus Chondrieae F. Schmitz et Falkenberg, 1897:432.

The tribe is represented by one genus in the northern Gulf 

of California.

Chondria C. Agardh

Chondria C. Agardh, 1817:xviii, 443.

Algae usually erect, rarely prostrate, composed of one to 

several axes arising from a common base. Axes are polysiphonous with 5 pericentral cells, but these are obscured from surface 

view by surrounding cortical layers of cells. Branches are mostly 

terete and irregularly and radially alternate; occasionally opposite or whorled. In those with several orders of branching, the 

smaller branches are reduced in diameter at their base. Apices 

have a terminal tuft of branched trichoblasts. Growth is from 

an apical cell that may be seen on or protrude from the apices or 

may be sunken in a terminal pit.

Tetrasporangia develop from pericentral cells and are 

tetrahedrally divided and formed in whorls of 1–3(–4), embedded beneath the cortical surface in the ultimate branches. 

Gametophytes are dioecious. Cystocarps are lateral on ultimate branches, covered by cortical layer. Spermatangial structures are generally a colorless flat disc with a sterile margin, 

discs borne in clusters at the branch apices (develop from 

trichoblasts).

Remarks. Chondria arcuata Hollenberg (1945) has 

been reported in the southern Gulf of California from Mazátlan, 

Sinaloa (Mendoza-González et al., 1994), and Jalisco (MendozaGonzález and Mateo-Cid, 1992), and in Pacific Mexico from 

Michoacán (Dreckmann et al., 1990; Sentíes-G. et al., 1990), 

and Oaxaca (León-Tejera et al., 1993).

Currently, three species of Chondria are recognized in the 

northern Gulf of California.

KEY TO THE SPECIES OF CHONDRIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Branch apices without a terminal depression; apices attenuate with protruding apical cell usually surrounded by trichoblasts; thalli usually epiphytic and iridescent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. acrorhizophora

1b. Apices of branches with apical cell of central axis sunken within a terminal depression from which tufts of trichoblasts 

may protrude . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Thalli 5–15 cm tall, mostly 500–1000 μm in diameter; irregularly alternately branched; outer cortical cells in surface view 

narrow-oblong and arranged in more or less longitudinal rows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. species A

2b. Thalli low growing, in part creeping; mostly less than 1 cm tall and 200–300(–400) μm in diameter; outer cortical cells 

in surface view rounded to polygonal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. repens
NUMBER 96 • 241

Chondria acrorhizophora Setchell et N. L. Gardner

FIGURES 117, 118B

Chondria acrorhizophora Setchell et N. L. Gardner, 1924:766, pl. 40: fig. 

b; Silva, 1991:465; González-González et al., 1996:190; Mateo-Cid et 

al., 2000:67; Mateo-Cid et al., 2006:57; Pacheco-Ruíz et al., 2008:212; 

Castañeda-Fernández de Lara et al., 2010:199.

Chondria tenuissima f. californica F. S. Collins, in Collins, Holden and Setchell, 1899:P.B.-A. No. 636.

Chondria californica (F. S. Collins) Kylin, 1941:41, pl. 12: fig. 35; Dawson, 

1944a:325; Taylor, 1945:294; Dawson, 1959a:36; 1963b:443, pl. 138: 

figs. 1, 2, pl. 139: figs. 1, 2, pl. 140: fig. 3; Abbott and North, 1972:75; 

Abbott and Hollenberg, 1976:724, fig. 673; Devinny, 1978:359; 

Huerta-Múzquiz, 1978:335; Stewart and Stewart, 1984:147; HuertaMúzquiz and Mendoza-González, 1985:54; Mendoza-González 

and Mateo-Cid, 1985:28; Santelices and Abbott, 1987:9; SalcedoMartínez et al., 1988:83; Sánchez-Rodríguez et al., 1989:46; Santelices, 1989:364, pl. Ñ: fig. 5; R. Aguilar-Rosas and Machado-Galindo, 

1990:188; Stewart, 1991:155; Ramírez and Santelices, 1991:363; 

Mateo-Cid and Mendoza-González, 1992:22; Mendoza-González and 

Mateo-Cid, 1992:20; Serviere-Zaragoza et al., 1993a:483; Mateo-Cid 

et al., 1993:49; González-González et al., 1996:190; Anaya-Reyna 

and Riosmena-Rodríguez, 1996:864, tbl. 1; Riosmena-Rodríguez et 

al., 1998:26; L. Aguilar-Rosas et al., 2000:132; CONANP, 2002:139; 

Pacheco-Ruíz and Zertuche-González, 2002:468; Fernández-García et 

al., 2011:61.

Chondria clarionensis Setchell et N. L. Gardner, 1930:158; GonzálezGonzález et al., 1996:190; Serviere-Zaragoza et al., 2007:9.

Algae erect, often bushy, of slender, mostly cylindrical, 

iridescent, densely branched axes, (1–)4–5(–8) cm high; occasionally on hard substratum, usually epiphytic, often attached 

to hosts by entangled tendril-like branchlets or by more or less 

prostrate lower axes with numerous discoid holdfasts. Branching irregularly alternate, multifarious, or somewhat distichous. 

Branches cylindrical, 185–225 μm in diameter, to compressed, 

350–550(–700) μm wide and 150–200 μm thick (flattening most 

prominent in young or low, basally attached thalli). Branch apices 

attenuate, with protruding apical cell of central axis surrounded 

by short tufts of trichoblasts; surfaces of axes and branches 

with few to many minute depressions throughout (representing 

branch primordia). Branchlets reduced in diameter at base. Pericentral cells 5 (not easily seen; more evident in young growing 

apices). Cortical cells variable, roundish to elongate (sometimes 

FIGURE 117. Chondria acrorhizophora: A. Habit of isotype (Marchant-44, US Alg. Coll.-56205). B. Habit (JN-6577, US Alg. Coll.-158967). 
242 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

up to 8 times longer than wide); lenticular thickenings usually 

present in walls of inner cortical cells.

Tetrasporangia borne in swollen ultimate branchlets; tetrasporangia up to 110 μm in diameter. Cystocarps scattered, subspherical to urceolate, 500–600 μm in diameter. Spermatangia 

unknown.

Habitat. Common from spring to summer, usually 

epiphytic on various algae, particularly on Sargassum, Digenea,

and articulated corallines; low intertidal to shallow subtidal, 

down to 8 m depths (also dredged from 4–32 m depths; Dawson, 1944a).

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de San Lucas; Nayarit to Jalisco. Eastern Pacific: Santa 

Cruz Island (California Channel Islands); southern California to 

Bahía Magdalena, Baja California Sur; Isla Guadalupe; Isla Clarión (Islas Revillagigedo); El Salvador; Costa Rica; Panama; Chile. 

Type Locality. Eureka, near La Paz, Baja California Sur, Gulf of California, Mexico.

Remarks. Chondria acrorhizophora was considered 

to be a highly polymorphic species by Dawson (1959a, 1963b, 

as “Chondria californica”), who also included C. clarionensis and several other taxa as synonyms. Two of these were recognized as subspecific taxa, C. californica f. concrescens (E. Y. 

Dawson) E. Y. Dawson (1963b:444; basionym: C. concrescens

E. Y. Dawson, 1961c:422) and C. californica f. cuscutoides (E. Y. 

Dawson) E. Y. Dawson (1963b:444; basionym: C. cuscutoides

E. Y. Dawson, 1945c:79). This northeastern Pacific Chondria 

acrorhizophora-californica-clarionensis complex likely includes 

more than one taxa and is in need of critical morphological and 

molecular study.

Chondria repens Børgesen

Chondria repens Børgesen, 1924:299, figs. 40, 41; Dawson, 1957c:24; 

1963b:448, pl. 168: fig. 2; Tanaka, 1963:66, fig. 4; Dawson, 1966a:30; 

Stewart and Stewart, 1984:147; Huerta-Múzquiz and MendozaGonzález, 1985:54; Santelices and Abbott, 1987:9; Ramírez and Santelices, 1991:363; Mateo-Cid and Mendoza-González, 1992:22; ServiereZaragoza et al., 1993a:483; González-González et al., 1996:191; Yoshida, 1998:1019; Fernández-García et al., 2011:61; Pérez-Estrada et 

al., 2012:191.

Algae terete, branched axes, forming low-growing turfs, 

up to 1 cm tall; of creeping and semi-erect axes and branches 

200–300(–400) μm in diameter; lowermost axes attached to substratum by small discs or haptera formed by bundles of rhizoids. 

Branches short, moderately constricted at base, with blunt apices; apical cell within terminal depression. Cortical cells rounded 

to polygonal with thick cell walls; central axis and pericentral 

cells not distinct.

Tetrasporangia in upper portions of slightly swollen ultimate tetrasporangial branchlets; tetrasporangia elliptical, 80–90 

μm in diameter. Cystocarps and spermatangia not observed in 

Gulf specimens.

Habitat. Attached to shells, coralline algae, mangroves, and other substrata; intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de La Paz; Nayarit to Jalisco. Eastern Pacific: Isla Guadalupe to Laguna de Ojo de Libre (Scammon’s Lagoon), Baja 

California Sur; El Salvador; Costa Rica; Rapa Nui (Easter Island; 

Isla de Pascua). Western Pacific: Japan; Vietnam.

Type Locality. Rapa Nui (Easter Island; Isla de 

Pascua), Valparaiso Region, Chile.

Chondria species A

FIGURE 118A

Chondria dasyphylla [in part, only Gulf of California] sensu Dawson, 

1944a:325; 1959a:37; 1963b:444, pl. 140: fig. 4, pl. 163; Hollenberg, 

1970:70, fig. 22; Abbott and Hollenberg, 1976:726, fig. 674; HuertaMúzquiz and Mendoza-González, 1985:54; Mendoza-González 

and Mateo-Cid, 1986:425; González-González et al., 1996:306; 

CONANP, 2002:139; L. Aguilar-Rosas et al., 2000:132; Cruz-Ayala 

et al., 2001:191; L. Aguilar-Rosas et al., 2002:235; Pacheco-Ruíz and 

Zertuche-González, 2002:468; Pacheco-Ruíz et al., 2008:212; PérezEstrada et al., 2012:191 [non Chondria dasyphylla (Woodward) 

C. Agardh, 1817:xviii; basionym: Fucus dasyphyllus Woodward, 

1794:239, pl. 23: figs. 1–3]. 

Algae 5.0–15 cm tall; of slender, flaccid, cylindrical axes and 

branches, 300–750(–1000) μm in diameter; branching multifariously in irregularly alternate arrangement, up to 3(–4) orders. 

Main axis usually not distinct; sometimes second- and thirdorder branches more or less percurrent. Ultimate branchlets 

simple, constricted at their base, with obtuse to truncate apices. 

FIGURE 118. Species of Chondria: A. Chondria species A: Small 

portion of alga to show branching habit (after Dawson, 1963b: pl. 

140: fig. 4, as “Chondria dasyphylla”). B. Chondria acrorhizophora: 

Detail of a branch tip to show papillate attachment structures (redrawn after Dawson 1963b: pl. 140: fig. 3, as “Chondria californica

f. cuscutoides”) . 
NUMBER 96 • 243

Apical cell of central filament sunken in terminal pit, with a protruding tuft of short trichoblasts. Outer cortical cells in surface 

view, narrow-oblong, arranged in more or less longitudinal rows. 

Medulla in transection of large, thin-walled cells, 75–300 μm.

Tetrasporangia borne abundantly in upper portions of 

ultimate branches; tetrasporangia 140–165 μm in diameter. 

Cystocarps subspherical to ovoid; borne lateral on branchlets. 

Spermatangia not observed in Gulf specimens. On the basis of 

Pacific Baja California specimens (Dawson, 1963b): spermatangial structures flat, colorless discs, circular to cordate, 500–600 

μm broad, each with a margin of large sterile cells and a system 

of branched veins; discs clustered at the branch tip; arising from 

the basal cell of a trichoblast.

Habitat. On rocks, low intertidal to shallow 

subtidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara); El Coloradito to Bahía San Luis Gonzága; 

Bahía Coyote (vicinity of Mulege) to Bahía de La Paz; Bahía San 

Carlos to Bahía Topolobampo. 

 Remarks. The northern Gulf of California “Chondria species A” are typically more delicate, slender, and diffusely 

branched than the coarser, erect forms of southern California (cf. 

Abbott and Hollenberg, 1976, as “C. dasyphylla”). Although 

both forms were referred to “C. dasyphylla” by Dawson (1944a, 

1963b), Gordon-Mills (1987) has suggested that the identification of all non-European records identified as Chondria dasyphylla are suspect. In the western Pacific, specimens from Korea 

identified as “C. dasyphylla” were found to differ and described 

as C. pellucida Y.-P. Lee (in Y.-P. Lee and Yoon, 1996). Thus, critical studies are needed of Gulf of California Chondria species A

(including Gulf specimens referred to “C. dasyphylla”) in order 

to resolve its taxonomic status and phylogenetic relationship to 

other species. Comparative morphological and molecular studies should include the Atlantic C. dasyphylla (type locality: Yarmouth, Norfolk, England; Maggs and Hommersand, 1993) C. 

pellucida (type locality: Hansu, Jeju, Korea; Y.-P. Lee and Yoon, 

1996; Y.-P. Lee, 2008), and two others from Pacific Mexico, C. 

pacifica Setchell et N. L. Gardner (1937; type locality: Bahía San 

Bartolomé, Baja California Sur) and C. telmoensis E. Y. Dawson (1946a; type locality: reef, Río San Telmo, Baja California). 

The latter two were earlier considered to be conspecific with “C. 

dasyphylla” by Dawson (1963b); however, the Gulf specimens of 

Chondria species A appear to be closest to C. pacifica. 

Digenea C. Agardh 

Digenea C. Agardh, 1822:388.

Algae are erect, often bushy, and composed of cartilaginous 

axes that are widely, dichotomously, subdichotomously or irregular laterally branched. The axes and branches are mostly 

densely covered by spirally arranged short, slender, stiff, simple 

to branched, determinate branchlets; they can sometimes be denuded in lower portions, probably from aging or possibly by 

grazing. The 5–12 pericentral cells are more apparent in the 

upper portions and branchlets but become obscured by the thickening pseudoparenchymatous cortex of mature portions. The 

inner cortical cells are large; the cells decreasing in size toward 

the outer cortical cell layers. The apical cell and small deciduous 

trichoblasts (usually observed on determinate branchlets) are at 

the tips of the branchlets. Branchlets develop 6-8 pericentral cells 

surrounded by a thin pseudoparenchymatous cortex.

Tetrasporangia in upper region of determinate branchlets; 

1 per swollen segment, with 3 cover cells. Cystocarps are ovoid, 

borne lateral or terminal on determinate branchlets. Spermatangia in flat, oval discs that replace the trichoblasts in the upper 

portion of the determinate branchlets.

Digenea simplex (Wulfen) C. Agardh

FIGURE 119

Conferva simplex Wulfen, 1803:17. 

Digenea simplex (Wulfen) C. Agardh, 1822:389; Setchell and Gardner, 

1924:769; Dawson, 1944a:326; Taylor, 1945:297; Dawson, 1959a:32; 

1963b:418, pl. 140: fig. 5, pl. 159: fig. 1; 1966a:29; Norris, 1973:16; 

Huerta-Múzquiz and Garza-Barrientos, 1975:11; Tseng, 1983:146, pl. 

76: fig. 4; Norris, 1985d:211; Huerta-Múzquiz and Mendoza-González, 

1985:54; Mendoza-González and Mateo-Cid, 1986:425; Mateo-Cid et 

al., 1993:49; Dreckmann and Sentiés G., 1994:443; Mateo-Cid and 

Mendoza-González, 1994b:41; González-González et al., 1996:308; 

Riosmena-Rodríguez et al., 1998:26; Yoshida, 1998:1021, fig. 3-

106E; Mateo-Cid et al., 2000:67; L. Aguilar-Rosas et al., 2000:132; 

CONANP, 2002:139; Cruz-Ayala et al., 2001:191; Mateo-Cid et al., 

2006:57; Serviere-Zaragoza et al., 2007:9; Berneckner, 2009:CD-Rom 

p. 67; Fernández-García et al., 2011:61.

Algae bushy, 3–15(–25) cm high, tough and cartilaginous; 

axes widely dichotomous or irregularly laterally branched; axes 

and branches usually densely (or occasionally sparsely) clothed 

with slender, stiff, usually simple determinate branchlets, 3–5(–

15) mm long; primary axes sometimes denuded in lower portions; attached by a discoid holdfast, that often spreads and may 

possibly coalesce with other holdfasts.

Tetrasporangia borne in distal, mostly uncorticated, portions of determinate branchlets. Cystocarps ovoid; terminal and 

lateral on the determinate branchlets. Spermatangia in small 

ovoid discs clustered at the apices of determinate branchlets.

Habitat. On rocks, often sand covered; mid to low 

intertidal, occasionally shallow subtidal. 

Distribution. Gulf of California: Puerto Peñasco 

to Cabo Pulmo. Eastern Pacific: Playa Los Cerritos (south of 

Todos Santos), Baja California Sur; Isla Socorro (Islas Revillagigedo); Costa Rica. Western Pacific: China; Japan.

Type Locality. Trieste, Gulf of Trieste, northeast 

Italy, Adriatic Sea.

Remarks. In the Gulf of California Digenea simplex can seasonally become heavily epiphytized by various other 

algae, particularly Jania and crustose corallines, and also by 

some sessile invertebrates, such as bryozoans. Gulf D. simplex

sometimes can be found growing on sand-covered substrate, and 

in areas where it is heavily grazed, it appears to persist by its 
244 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

spreading crustose base (a morphological form resistant to grazing; cf. Lewis et al., 1987).

The natural products of this alga have long been used in 

medicine as an anthelmintic agent (vermifuge) (e.g., Michanek, 

1975, Tseng, 1983; Kimura et al., 1996). Studies of Pakker et 

al. (1996) found ecological and evolutionary differentiation 

between disjunct populations of Digenea simplex, with Pacific 

isolates having a wider temperature range than those of the Atlantic. It will be interesting to similarly investigate those of the 

northern and southern Gulf of California to test their origins 

and relationships with those of the Indo-Pacific and type locality.

Rhodomelaceae tribus Herposiphonieae

Rhodomelaceae tribus Herposiphonieae F. Schmitz et Falkenberg, 1897:457.

Thalli are composed of an erect upper portion and a lower 

prostrate portion or may be entirely prostrate. Members are 

polysiphonous, ranging from 4 to 18 pericentral cells, and usually not corticated. Indeterminate and determinate branches are 

exogenous and in a regular (defined) sequence. Determinate 

laterals are usually unbranched or sometimes slightly to regularly branched. Indeterminate axes are subcylindrical to compressed, and bilateral or radially arranged. Apices are usually 

dorsiventrally developed, and often curved upward. Axes are 

attached by rhizoids produced from the ventral or lateral pericentral cells. Trichoblasts are usually present on determinate laterals, although they may be rare.

Tetrasporangia with 2–3 cover cells, are 1 per segment 

within straight to curved determinate laterals. Gametophytes are 

mostly dioecious but a few are monoecious. Procarps develop on 

lower cells of trichoblasts, with the fertile axial cells becoming 

polysiphonous. Cystocarps are globose, ovate to urn-like, with 

an ostiolate pericarp. Spermatangial structures ovoid to lanceolate on modified trichoblasts.

The tribe of seven known genera is represented by one genus 

in the northern Gulf of California.

Herposiphonia Nägeli 

Herposiphonia Nägeli, 1846:238.

Algae are polysiphonous and completely ecorticate, with 

each species having a characteristic number of pericentral cells. 

Thalli consist of indeterminate creeping axes that bear distichous 

or erect and parallel determinate and indeterminate branches in a 

regular sequence, and are attached by numerous rhizoids cut off 

from the distal end of the ventral pericentral cells. Determinate 

FIGURE 119. Digenea simplex: A. Habit of a specimen dense with slender, stiff branchlets; lowermost portion was partly buried in sand (JN4204, US Alg. Coll.-159105). B. Axes with many branchlets missing, probably removed by grazing herbivores (JN-4204, US Alg. Coll.-159104).
NUMBER 96 • 245

branches are usually unbranched, and sometimes may have subterminal trichoblasts. Thalli are often epiphytes or in algal turfs.

Tetrasporangia are tetrahedrally or obliquely cruciately divided, and 1 per segment in a series, within central portions of 

determinate branches. Cystocarps are ovoid to urceolate, and 

lateral or subterminal on determinate branches. Spermatangial stichidia are cylindrical to ovoid, borne on branches of the 

trichoblasts on determinate branches, and may end in a terminal 

sterile cell or cells.

Remarks. Two species are reported in the southern 

Gulf: Herposiphonia hollenbergii E. Y. Dawson (1963b) from 

Cabo San Lucas (Dawson, 1963b), Bahía Concepción (MateoCid et al., 1993) and Cabo Pulmo (Mateo-Cid et al., 2000), and 

H. verticillata (Harvey) Kylin (1925; basionym: Polysiphonia 

verticillata Harvey, 1833) from Bahía Concepción (Mateo-Cid 

et al., 1993).

Three species of Herposiphonia, one with two taxonomic 

varieties, occur in the northern Gulf.

KEY TO THE SPECIES OF HERPOSIPHONIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Determinate branches ending in a colorless spine of several cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. spinosa

1b. Determinate branches ending in blunt cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Determinate branches from alternate sides of successive segments of axes, distichously arranged (in 1 plane) . . . . . . . . 3

2b. Determinate branches not alternate, nor distichously arranged,erect from prostrate axes, unbranched and parallel to each 

other . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. littoralis

3a. Indeterminate branches long in lower portions, becoming shorter above, strictly distichous . . . . . H. plumula var. plumula

3b. Indeterminate branches mostly remaining rudimentary throughout, slightly offset from distichous; generally smaller . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. plumula var. parva

Herposiphonia littoralis Hollenberg

FIGURE 120

Herposiphonia littoralis Hollenberg, 1970:69, figs. 16–18; Abbott and 

Hollenberg, 1976:718, fig. 666; Pedroche and González-González, 

1981:68; Pacheco-Ruíz and Aguilar-Rosas, 1984:74; Dreckmann et al., 

1990:32; Sentíes-G. et al., 1990:103, pl. 6; Stewart, 1991:157; ServiereZaragoza et al., 1993a:483; Stout and Dreckmann, 1993:16; GonzálezGonzález et al., 1996:223; Riosmena-Rodríguez et al., 1998:26; 

Hernández-Herrera et al., 2005:147; Fernández-García et al., 2011:62.

Herposiphonia secunda sensu Huerta-Múzquiz and Garza-Barrientos, 

1975:9; Huerta-Múzquiz and Mendoza-González, 1985:54; MendozaGonzález and Mateo-Cid, 1985:30 [non Herposiphonia secunda

(C. Agardh) Ambronn, 1880:197; basionym: Hutchinsia secunda C. 

Agardh, 1824:149].

Herposiphonia tenella sensu Setchell and Gardner, 1930:164; Hollenberg, 

1948:159; Dawson, 1944a:334, pl. 49: fig. 1; 1959a:34; 1961b:452; 

1963b:435, pl. 140: fig. 1; Huerta-Múzquiz and Tirado-Lizárraga, 

1970:129; Chávez-Barrear, 1972b:269; Huerta-Múzquiz and GarzaFIGURE 120. Herposiphonia littoralis: A. Portion of thallus showing pattern of three determinate branches between indeterminate branches. 

B. Portion near apex showing young indeterminate branches slightly offset from determinate branches, one branch per segment with rhizoids 

(A, B, JN-5153, US Alg. Coll. microscope slide 4946).
246 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Barrientos, 1975:9; Huerta-Múzquiz and Mendoza-González, 1985:54; 

Mendoza-González and Mateo-Cid, 1985:30; Mendoza-González 

and Mateo-Cid, 1986:425; Dreckmann et al., 1990:32; Sentíes-G. et 

al., 1990:106, pl. 8; Mateo-Cid and Mendoza-González, 1992:22; 

Serviere-Zaragoza et al., 1993a:483; Mateo-Cid and MendozaGonzález, 1994b:42 [non Herposiphonia tenella (C. Agardh) Ambronn, 1880:197; basionym: Hutchinsia tenella C. Agardh, 1828:105; 

which is now Herposiphonia secunda f. tenella (C. Agardh) M. J. 

Wynne, 1985e:173].

Herposiphonia secunda f. tenella sensu Stout and Dreckmann, 1993:16; 

Anaya-Reyna and Riosmena-Rodríguez, 1996:864, tbl. 1; RiosmenaRodríguez et al., 1998:26; L. Aguilar-Rosas et al., 2000:132; CONANP, 

2002:139; Mateo-Cid et al., 2006:57; Serviere-Zaragoza et al., 2007:10 

[non Herposiphonia secunda f. tenella (C. Agardh) Wynne, 1985e:173]. 

Algae dorsiventrally organized with creeping, prostrate 

axes of unlimited growth (indeterminate), (40–)80–175 μm in 

diameter, and simple, erect branches of limited growth (determinate) often arching distally. Prostrate axes attached by numerous, unicellular rhizoids, 1 or more per segment, cut off from the 

distal ends of ventral pericentral cells. Axes polysiphonous, of 

9–10(–12) pericentral cells. Branches 1 per segment, in a regular pattern of 3 consecutive determinate branches between each 

indeterminate branch. Determinate branches arising dorsally, 

unbranched, 20–27(–40) segments long; middle portions 30–80 

μm in diameter; narrowed at their base, with subacute to blunt 

tips. Indeterminate branches often developing from alternate 

sides of prostrate axes slightly offset from determinate branches, 

indeterminate axes relatively rudimentary near growing apices 

of prostrate axes, apices ascending, often inrolled. As growth 

continues, the indeterminate branches subsequently grow out to 

become prostrate axes and repeat this branching pattern. Short 

trichoblasts sometimes present, abundantly branched; subterminal or terminal on both determinate and indeterminate branches.

Tetrasporangia about 40–45 μm in diameter; borne in a 

series, 1 per segment in determinate branches. Gametophytes 

dioecious. Cystocarps usually terminal, sometimes subterminal, 

on determinate branches. Spermatangial thalli occasionally with 

an irregular pattern of determinate and indeterminate branches, 

and not as regularly 1 per segment; spermatangial structures 

cylindrical, slightly incurved, about 200 μm long, 30–40 μm in 

diameter, with 1–2 terminal sterile cells; borne above a 1-celled 

pedicel on modified trichoblasts of determinate or indeterminate 

branches (after Dawson, 1963a).

Habitat. Growing on rocks, in algal turfs, or epiphytic; intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabo San Lucas; Nayarit to Jalisco; Isla María Magdalena 

(Islas Marías; =Islas Tres Marías). Eastern Pacific: Santa Catalina 

Island (California Channel Islands); Conora del Mar, southern 

California to Playa Los Cerritos (south of Todos Santos), Baja 

California Sur; Isla Socorro, Isla Clarión and Isla San Benedicto 

(Islas Revillagigedo); Jalisco to Oaxaca; El Salvador.

Type Locality. Corona del Mar, Orange County, 

southern California, USA.

Herposiphonia plumula (J. Agardh) Hollenberg var. plumula

FIGURE 121

Polysiphonia plumula J. Agardh, 1885:99; Falkenberg, 1901:317.

Herposiphonia plumula (J. Agardh) Hollenberg, 1970:68, fig. 21 [type 

specimen]; Abbott and Hollenberg, 1976:718, fig. 667; Pacheco-Ruíz 

and Aguilar-Rosas, 1984:74; Sánchez-Rodríguez et al., 1989:46; Scagel et al., 1989:194; R. Aguilar-Rosas et al., 1990:126; Sentíes-G. et 

al., 1990:103, pl. 7; Stewart, 1991:157; González-González et al., 

1996:223; CONANP, 2002:139; Riosmena-Rodríguez et al., 2005a:33; 

Pacheco-Ruíz et al., 2008:212.

Herposiphonia rigida N. L. Gardner, 1927f:100, pl. 23: figs. 1, 2 [type specimen], pl. 21; Smith, 1944:369, pl. 95: fig. 5, pl. 96: fig. 3.

Herposiphonia subdisticha sensu Dawson, 1944a:334 [in part], pl. 49, fig. 

2; 1953c:3; 1959a:32; 1963b:433, pl. 141: figs. 4, 5 [in part]; Stewart and Stewart, 1984:147 [non Herposiphonia subdisticha Okamura, 

1899:37; see Hollenberg, 1968c:555].

Thalli of uncorticated, terete, polysiphonous, creeping and 

erect portions, 5–20(–30) mm tall, main axes with 8–12(–14) 

pericentral cells, up to 300 μm in diameter. Distichously 

branched on every segment, with 3 (rarely 4) alternate determinate branches between successive alternate indeterminate 

branches. Indeterminate branches on same side of axes as determinate branch on segment below it. Determinate branches unbranched, polysiphonous with (6–)7–10(–12) pericentral cells, 

150–190 μm in diameter at their base, curved toward the branch 

tip, short, mostly 0.5–1.0(–2) mm long, tapering to acuminate or 

blunt tip. Indeterminate branches 10–17 segments long or more, 

branched similar to main axis; progressively shorter in length 

toward the thallus apex. Trichoblasts frequently absent.

Tetrasporangia spherical, about 60 μm diameter, obliquely 

cruciately divided, borne in straight series in the determinate 

branches. Cystocarps sessile, ovoid, 300–450 μm in diameter 

and up to 600 μm long, borne singly on the adaxial side of determinate branches. Spermatangial stichidia cylindrical and incurved, 1 to several on the adaxial side of determinate branches.

Habitat. Epiphytic on various algae, especially on 

articulated corallines; low intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to San José del Cabo. Eastern Pacific: Alaska to Bahía Magdalena, Baja California Sur; Islas Todos Santos and Isla Guadalupe, 

off Baja California; Colima to Oaxaca.

Type Locality. Santa Barbara, Santa Barbara 

County, southern California, USA. 

Herposiphonia plumula var. parva (Hollenberg) Hollenberg

FIGURE 122

Herposiphonia parva Hollenberg, 1943:575, figs. 8, 9; Dawson, 1945d:65; 

Hollenberg and Abbott, 1966:116; Smith, 1969:726; Stewart, 1991:158. 

Herposiphonia plumula var. parva (Hollenberg) Hollenberg, 1970:69; 

González-González et al., 1996:223. 

Herposiphonia pygmaea Hollenberg in G. M. Smith, 1944:369, pl. 96: fig. 

2, nom. invalid.

Herposiphonia subdisticha [in part] sensu Dawson, 1944a:334, pl. 49: 

fig.2; 1959a:32; 1960a:51; 1961a:452; 1963b:433, pl. 141: figs. 4, 5; 
NUMBER 96 • 247

1966a:30; González-González et al., 1996:224 [non Herposiphonia 

subdisticha Okamura, 1899:37].

Although similar to Herposiphonia plumula var. plumula,

H. plumula var. parva is distinguished in being smaller, with indeterminate branches that mostly remain rudimentary.

Habitat. Usually epiphytic on other algae; in tide 

pools and low intertidal to shallow subtidal. 

Distribution. Gulf of California: Puerto Peñasco. 

Eastern Pacific: Oregon; central California to Santa Cruz Island, 

off southern California; Punta Banda, Baja California.

Type Locality. Lady’s Harbor, Santa Cruz Island, 

California Channel Islands (Channel Islands Marine Park), 

southern California, USA.

Herposiphonia spinosa E. Y. Dawson

FIGURE 123

Herposiphonia spinosa E. Y. Dawson, 1959a:34, fig. 7B; 1961b:452; 

1963b:432, pl. 129: fig. 2; 1966a:30; 1966b:66; Schnetter and 

FIGURE 121. Herposiphonia plumula var. plumula: Portion 

of thallus showing pattern of determinate and indeterminate 

branches (JN-4301b, US Alg. Coll. microscope slide 4913). 

FIGURE 122. (Left) Herposiphonia plumula var. parva: A. Portion 

showing arrangement of determinate and indeterminate branches. 

B. Determinate branch with tetrasporangia in straight series (A, B, 

after Hollenberg, 1943: figs. 9, 8).
248 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Bula-Meyer, 1982:187, pl. 36: fig. I; Bula-Meyer, 1995:39; GonzálezGonzález et al., 1996:224; Anaya-Reyna and Riosmena-Rodríguez, 

1996:864, tbl. 1; Pacheco-Ruíz and Zertuche-González, 2002:468; 

Pacheco-Ruíz et al., 2008:212. 

Thalli of creeping, polysiphonous main axes of (8–)10–12 

pericentral cells (130–240 μm in diameter) and erect determinate branches of 6–8 pericentral cells (120–150 μm in diameter 

at base, narrowing above); attached by numerous unicellular 

rhizoids issued from ventral pericentral cells, occasionally terminating with a digitate disc. Indeterminate branches at every 

fourth segment, separated by 3 determinate branches. Determinate branches arising from dorsal side of prostrate axes, once or 

twice forked, rigid, divaricate, and slightly recurved, acuminate 

with a series of colorless cells (usually 3) forming a point (spine). 

Trichoblasts occasionally present, compound, usually on the 

fourth or fifth segment back from the spine at tip of branches.

Reproductive structures not observed.

Habitat. On rocks and in tide pools, found creeping 

among other algae or epiphytic on Sargassum and Amphiroa and 

probably other larger algae as well; mid intertidal to very shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de Los Ángeles; Isla Tiburón; Isla Partida (east of Bahía 

de La Paz) to Punta Los Frailes; Cabo San Lucas. Eastern Pacific: 

Isla Gorgona, Colombia.

Type Locality. Isla Partida (off the north end of Isla 

Espíritu Santo), Baja California Sur, Gulf of California, Mexico.

Rhodomelaceae tribus Laurencieae

Rhodomelaceae tribus Laurencieae F. Schmitz, 1889:447; Womersley, 

2003:452.

The tribe includes members that are (1) erect and branched 

macrophytes; branchlets with an apical cell sunk within an apical depression with a cluster of trichoblasts; axial and pericentral 

cells more readily observed in uppermost developing branchlets 

(becoming obscured within extensive cortex below apices); and 

(2) minute, subspherical to cushion-shaped parasites (e.g., Janczewskia Solms-Laubach, 1877).

Tetrasporangia subspherical to ovoid, mostly tetrahedrally 

divided; in outer cortex; developed on upper end of elongated 

pericentral cells or cut off from outer cortical cells, with 2 cover 

cells. Gametophytes are dioecious. Procarps develop on lower cells 

of trichoblasts; carpogonium of 4 cells and 2 sterile groups of cells. 

Cystocarps pedicellate, partly immersed, or sessile; with ostiolate 

pericarp, corticated, 3–6 cell layers thick. Spermatangia develop 

within cup-shaped receptacles in apical pits of branchlets to deep 

urn-shaped pockets in branchlets, either on modified trichoblasts 

formed by axial cells in apical pits (“trichoblast type”) or from 

filaments formed by apical and epidermal cells (“filament type”).

FIGURE 123. Herposiphonia spinosa: A. Habit (JN-4390, US Alg. Coll. microscope slide 4912). B. Colorless 3-celled spine at tip of determinate 

branch (JN-3175, US Alg. Coll. microscope slide 4907). 
NUMBER 96 • 249

Remarks. Laurencia had long been recognized as a 

broadly defined genus. Saito (1967) divided the genus Laurencia

into two subgenera, Laurencia subgen. Laurencia and L. subgen. Chondrophycus J. Tokida et Saito. Within the last 20 years, 

morphological, anatomical, molecular and genetic data have 

supported its separation into several genera (see Nam and Sohn, 

1994; Garbary and Harper, 1998; Nam et al., 2000; McIvor et 

al., 2002; Lewis et al., 2008; Martin-Lescanne et al., 2010; Nam, 

2011). A reinterpreted Laurencia, Chondrophycus (J. Tokida 

et Saito) Garbary et J. Harper (1998), and Osmundea Stackhouse (1809) were recognized within the “Laurencia-complex” 

(Garbary and Harper, 1998; Nam et al., 2000; McIvor et al., 

2002; Fujii et al., 2006). More recently described are the genera Palisada K. W. Nam (2007), and Yuzurua Martin-Lescanne 

(in Martin-Lescanne et al., 2010). A sixth genus, Laurenciella 

Cassano, Gil-Rodríguez, Sentíes, Díaz-Larrea, M. C. Oliveira et 

M. T. Fujii (in Cassano et al., 2012), was separated by molecular 

sequence data, but the genus apparently cannot be distinguished 

from Laurencia solely on morphological characters. There is the 

possibility that Corynecladia J. Agardh (1876), currently treated 

as a synonym of Laurencia, might also be a separate genus (see 

Nam, 2006). The proposed subgenus Saitoa G. Furnari et Serio, 

1993, nom. illeg. (McIvor et al., 2002), if found to be distinct 

could not be used for a genus name since it would be a later homonym of Saitoa C. Rajendran et B. Muthappa (1980). 

There are some overlapping morphological characters as 

well as exceptions to the diagnostic characters used for separation of both generic and subgeneric taxa. To accommodate 

the differences within Chondrophycus, Nam (1999) proposed 

other subgenera. Two of these have secondary pit connections 

between the outer cortical cells and two sterile pericentral cells 

in tetrasporangial axial segments but differ in the arrangement 

of tetrasporangia; that is, in C. subgen. Chondrophycus tetrasporangia are in a right-angle pattern, whereas in C. subgen. 

Kangjaewonia K. W. Nam (1999) they are in a parallel pattern. 

The third, C. subgen. Yuzurua K. W. Nam (1999), is now a 

genus, Yuzurua, and also has a right-angle arrangement of tetrasporangia, a character shared with some species of Chondrophycus. Yuzurua differs from Chondrophycus (which has two 

sterile pericentral cells in tetrasporangial axial segments) in having only one sterile pericentral cell in its tetrasporangial axial 

segments. The presence or absence of secondary pit connections 

in the outer cortical cells separates two of the genera: Yuzurua

has secondary pit connections between epidermal cells, whereas 

Palisada lacks them. 

Whereas only one genus, Laurencia, was once known in the 

Gulf of California, currently four of the six genera of the tribe 

Laurencieae—Laurencia, Chondrophycus, Osmundea, and Palisada—are recognized in the northern Gulf of California.

KEY TO THE GENERA OF LAURENCIEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli of Gulf species compressed to flattened; 2 pericentral cells per axial segment in vegetative axes; corp en cerise (gland 

cells) absent; tetrasporangia produced from random epidermal (cortical) cells; “filament type” spermatangial development 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Osmundea

1b. Thalli terete to subterete; either with 2 or 4 pericentral cells per axial segment in vegetative axes; corp en cerise absent or 

present; tetrasporangia produced from particular pericentral cells; “trichoblast-type” spermatangial development. . . . . . 2

2a. Vegetative axial cell with 2 pericentral cells (seen only near branchlet apices) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2b. Vegetative axial cell with 4 pericentral cells (seen only near branchlet apices); corps en cerise often present within cortical 

cells and trichoblasts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Laurencia

3a. Tetrasporangial axial segments with 1 sterile pericentral cell (1st pericentral cell); spermatangial branches develop from 

1 of 2 laterals on the suprabasal cell of trichoblasts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Palisada

3b. Tetrasporangial axial segments with 2 sterile pericentral cells (1st and 2nd); spermatangial branches produced from 2 

laterals on the suprabasal cell of a trichoblast but one remains partly sterile . . . . . . . . . . . . . . . . . . . . . Chondrophycus

Laurencia J. V. Lamouroux

Laurencia J. V. Lamouroux, 1813:130, nom. cons. (see Papenfuss, 1947b:15).

Thalli cylindrical to subcylindrical, mostly radial, bilateral, 

or irregularly branched and attached by discoid, stoloniferous, 

or encrusting holdfasts. Apical cell always sunk in small terminal 

apical pit of branchlet and surrounded by branched, colorless deciduous trichoblasts. Central axial cell row (filament) with 4 pericentral cells per axial segment in vegetative axes; first pericentral 

cell is under a trichoblast (usually only distinguishable near apical 

cell, becoming obscured by formation of an extensive pseudoparenchymatous cortex). Secondary pit connections are present 

between adjacent epidermal cells. Spherical refractive inclusions, 

the corps en cerise (gland cells), are often present in cortical cells 

and trichoblast cells; they are thought to be the site of synthesis 

and/or storage of halogenated secondary metabolites (Young et 

al., 1980). Medullary cells are with or without lenticular thickenings, their abundance varying from sparse to frequent. Quantitative differences in the amount of lenticular thickenings (seen in 

sections) can vary between those in cells of the main axis, each 

order of branches, and the ultimate branchlets within thalli of the 

same species and sometimes in the same individual thallus.

Tetrasporangia axial segments develop near the apical cells 

of branchlets, with tetrasporangia produced from particular 

pericentral cells. Each tetrasporangial axial segment has two 

sterile pericentral cells, including the second pericentral cell. 
250 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Procarps are borne on lower cells of modified trichoblasts with 

segments of five pericental cells in the apical pits. Cystocarps are 

ostiolate, noticeably protruding above branchlet and sometimes 

branch surfaces. Spermatangial branches develop in cup-shaped 

depressions that are lateral or terminal on ultimate branchlets. 

Spermatangial branches are produced from one of the two laterals on the suprabasal cell of the trichoblasts; the other lateral 

remains sterile. 

Remarks. Species of Laurencia are found worldwide 

in tropical to temperate habitats from the intertidal to subtidal. 

Most species of Laurencia synthesize at least one specific secondary metabolite that is not found in other Laurencia species 

(Fenical, 1975; Fenical and Norris, 1975; Norris and Fenical, 

1982; Faulkner, 1984; Norris and Fenical, 1985). Howard et al. 

(1980a, 1980b) found the unique natural chemistry of several 

species of Laurencia remained constant under varying conditions 

in the field and in culture. The chemotaxonomic value of these 

compounds has been supported in several studies (e.g., Howard et al., 1980b; McDermid, 1988a; Masuda et al., 1996; GilRodríguez et al., 2009).

Agar has been described in the cell wall polysaccharides 

from a few of the species—for example, Laurencia flexilis

Setchell (1926) from China, where it is commercially harvested 

(Tseng, 1983; Wu and Zeng, 1985), and Laurencia sp. from Hawaii (Zablackis and McDermid, 1988). It would be interesting 

to investigate the polysaccharide chemistries of species from the 

northern Gulf of California.

The southern Gulf of California endemic Laurencia subcorymbosa E. Y. Dawson (1963a) described from Cabo Pulmo has 

also been reported from Punta Palmilla and Punta Los Frailes 

(Dawson, 1963) and Bahía de La Paz (Huerta-Múzquiz and 

Mendoza-González, 1985). Four others, originally described from 

Pacific Mexico, have also been recorded in the southern Gulf: L. 

masonii Setchell et N. L. Gardner (1930) and L. decidua E. Y. 

Dawson (1954a) from Bahía de La Paz (Huerta-Múzquiz and 

Mendoza-González, 1985), L. voragina W. R. Taylor (1945) from 

Punta Arena (Mateo-Cid et al., 2000), and L. richardsii E. Y. Dawson (1954a) from Mazátlan (Mendoza-González et al., 1994).

Currently there are six species of Laurencia in the northern 

Gulf of California, including three new species described herein.

KEY TO THE SPECIES OF LAURENCIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Alga of terete axes; distinctly bright to dark green (sometimes almost blackish green) . . . . . . . . . . . . . . . . L. johnstonii

1b. Alga of terete axes; not green, usually reddish to blackish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Algae semierect, low-growing clumps, less than 3 cm tall; in spreading low turfs or mats . . . . . . . . . . . . . . . . . . . . . . 3

2b. Algae erect, larger and taller, individuals or clumps up to 15 cm tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

3a. Loose clumps, comparatively shorter and thinner, 1.5–2.5 cm tall; branches narrow, 300–500 μm in diameter; ultimate 

branchlets contracted at base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. hancockii

3b. Dense clumps, up to 3 cm tall, often forming turfs; branches wider, 700–850 μm in diameter . . . . . . . . . . . . . . L. lajolla

4a. Thalli very lax, axes (700–)1000 μm in diameter, branches mostly 300–500 μm in diameter; branching irregularly alternate; ultimate branches densely crowded; contain the brominated diterpene iriediol . . . . . . . . . . . . . . . . . . . . . . L. iriei

4b. Thalli not lax; ultimate branches not densely crowded; do not contain iriediol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5a. Algae bright red, main axis 700–1000 μm in diameter, with branches mostly 500–700 μm in diameter; branching irregularly alternate, with long intervals between branches in lower portions, intervals become shorter upwards; with small 

ultimate branches; contains halogenated sesquiterpenes similar to elatol . . . . . . . . . . . . . . . . . . . . L. aguilar-rosasorum

5b. Algae dark red to blackish, thin and rigid; axes and branches of more or less uniform diameter, mostly about 500 μm in 

diameter; branching mostly opposite (occasionally alternate), with fewer ultimate branchlets; has acetylene-containing 

compound chondriol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. fenicalii

Laurencia aguilar-rosasorum J. N. Norris, sp. nov.

FIGURE 124A

Laurencia pacifica sensu Dawson, 1963b:457 [in part; only among Gulf of 

California specimens; non Laurencia pacifica Kylin, 1941:42].

Laurencia sp. III of Fenical and Norris, 1975:106, figs. 2, 3.

Latin Description. Thalli ruborem rosae purpureus, laxa, usque cm 15, unius plures, ramosi teretes, axes plus 

minus pyamidal habitu prima 0.7–1.0 mm axes diametro, irregulariter alterne ramosae usque 4(–6) iussione intervalla iam in inferiora rami, ramo breviores spatio sursum ramos 500–700 μm 

FIGURE 124. (Opposite) Species of Laurencia. A. Laurencia aguilar-rosasorum, sp. nov.: Holotype specimen (JN-4369, US Alg. Coll.-217740). 

B. Laurencia fenicalii, sp. nov.: Holotype specimen (JN-4515, US Alg. Coll.-217741). C. Laurencia iriei, sp. nov.: Holotype specimen (JN-4519, 

US Alg. Coll.-217742). D. Laurencia johnstonii: Habit (JN-4068, US Alg. Coll.-160140).
NUMBER 96 • 251
252 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

diametro, basi leviter angustata plerumque ramum origine ultima 

denique ramulis plerumque 250–500 μm longae, apices rotundatos, de similis diametro ramulis magis rotundato; circumdederunt 

securibus ramis brevibus numerosis, ramulis papillosis; appensa 

stolonifera holdfast pronus implicuit brachia; distinguitur chemica L. fenicalii e L. iriei secunda sua naturali product praedominantis, similiter apud halogenated elatol sesquiterpenes.

Algae rose red to bright red, lax, up to 15 cm tall; of 1 to several terete multifariously branched axes, more or less pyramidal in 

appearance; primary axes 700–1000 μm in diameter, irregularly 

alternately branched up to 4(–6) orders, with longer intervals between branches in lower portions, branch interval shorter upward; 

branches 500–700 μm in diameter, basally usually slightly narrowed at branch origin; ultimate branchlets short, mostly 250–

500 μm long, with rounded apices, of similar diameter; axes and 

branches beset with numerous short, papillate branchlets; attached 

by holdfast and entangled stoloniferous prostrate branches.

Reproductive structures not observed.

Habitat. On rocks and tidal platform and in tide 

pools; mid to low intertidal.

Distribution. Gulf of California: Puerto Peñasco 

and vicinity.

Holotype. JN-4369 (US Alg. Coll.-217740).

Type Locality. Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Gulf of California, Mexico.

Etymology. Laurencia aguilar-rosasorum is named 

for two marine botanists, brothers Luis Ernesto Aguilar-Rosas 

(Instituto de Investigaciones Oceanológicas, Universidad de 

Baja California, Ensenada) and Raúl Aguilar-Rosas (Facultad de 

Ciencias Marinas, Universidad de Baja California, Ensenada), in 

recognition of their contributions to our knowledge of the marine algae of Baja California and the Gulf of California (many of 

their publications are cited herein).

Remarks. Three separate morphological forms were 

found within a broadly defined concept of “Laurencia pacifica” 

sensu Dawson (1963b) in the upper Gulf of California. Each of 

these was recognized to be distinct from Laurencia pacifica Kylin 

(see Fenical and Norris, 1975: figs. 2, 3; Howard et al., 1980b) 

on the basis of differences in their unique natural product chemistries and morphologies. The three of the upper Gulf can be 

distinguished from each other by their own characteristic secondary metabolites. Chemically, Laurencia aguilar-rosasorum is 

distinguished from the other two, L. fenicalii and L. iriei, by its 

predominant secondary natural product, a halogenated sesquiterpene similar to elatol (Sims et al., 1974). (See also Remarks 

under L. fenicalii and L. iriei.)

Laurencia fenicalii J. N. Norris, sp. nov.

FIGURE 124B

Laurencia pacifica sensu Dawson, 1963b:457 [in part; only among Gulf of 

California specimens; non Laurencia pacifica Kylin, 1941:42].

Laurencia sp. I of Fenical and Norris, 1975:106, figs. 2, 3; Howard and Fenical, 1975:1687.

Chondria oppositiclada sensu Sims et al., 1974:3774; Fenical et al., 

1974:1507 [non Chondria oppositiclada E. Y. Dawson, 1945d:78]. 

Latin Description. Thalli fasciculus, ad cm 10, 

brunneo-rufa of nigricantes rubent comparative teretes rigidi axibus 500 μm diametro, plerumque opposite ramosae usque 4(–6) 

iubet (uel ramis interdum alternis) plus quam planum de ramis 

350–500 μm diametro attachiatus est per holdfast discoidea, secundario prostrata ramis parvis; rami leviter constrictum basi 

rotundatis apicibus; segmenta fere longiores inter ramos basi 

angustata ramulis ultimis sensim ad apices antice, 200–350 μm. 

Medulla cellulis hyalinis magna, lenticellis inspissato nulla, cortical cells videtur exteriora sine hospitibus secunda lacum. Subsperical tetrasporangiis, 72–96 μm longa, 70–85 μm diametro, 

ramulis ultimis in. Cystocarpic subglobosa, sessilia, 500–600 μm 

diametro, ostiolo in, ferme 1–2, plerumque in ramis lateralibus 

ramulis ultimis et. Spermatangia puteos in vado plures in ultimas 

superne ramulis; racemis spermatangial magna sterilis terminalis 

cellula apicalis subglobosa 10–15 μm longa, 8–10 μm diametro.

Distinguitur chemica L. iriei e L. aguilar-rosasorum praedominantis secunda sua naturalia, et chondrin chondriol et alia sesquiterpenoid plicia etiam cycloeudesmene.

Algae in clumps, up to 10 cm tall; of brownish red to blackish red, comparatively rigid terete axes, thin, 500 μm in diameter, 

mostly oppositely branched up to 4(–6) orders (or only occasionally with alternate branches) in more than 1 plane; branches 

about 350–500 μm in diameter; attached by a discoid holdfast 

and secondarily by short prostrate branches. Branches slightly 

narrower at base, with rounded apices; most with long intervals 

between branches; ultimate branchlets narrowed basally, gradually widening toward apices, 200–350 μm in diameter. Medulla 

of large colorless cells; lenticular thickenings absent. Outer cortical cells apparently without secondary pit connections.

Tetrasporangia subspherical, 72–96 μm long, 70–85 μm in diameter, in ultimate branchlets. Cystocarps subglobose, sessile, 500–

600 μm in diameter, with an ostiole; usually 1–2, mostly lateral on 

branches and ultimate branchlets. Spermatangia clustered in shallow 

cup-shaped pits, several on upper ends of spermatangial ultimate 

branchlets; spermatangia on whorled branchlets, each with a large, 

subglobose, sterile terminal cell, 10–15 μm tall, 8–10 μm in diameter.

Habitat. On rocks, in tide pools, and on tidal platforms; mid to low intertidal.

Distribution. Gulf of California: Puerto Peñasco 

and vicinity to Punta Cirio (south of Puerto Libertad), and Bahía 

San Carlos, northwest of Guaymas, Sonora.

Holotype. JN-4515 (US Alg. Coll.-217741), Coll. 

J. N. Norris and K. E. Bucher, 9 November 1973.

Paratypes. Cumpleaños Tide Pool, Playa Las Conchas 

(Playa Estación), Puerto Peñasco (all coll. J. N. Norris and K. E. 

Bucher): JN-4314 (spermatangial) (US Alg. Coll.-160355); microscope slide 5092 & JN-4320 (spermatangial) in tidal runoff from 

Cumpleaños Tide Pool, 24 October 1973, and JN-4513, 9 November 1973; and tidal platform, Playa Las Conchas (Playa Estación), 

JN-4372. Punta Cirio (south of Puerto Libertad): JN-4876, Coll. 

J. N. Norris, K. E. Bucher & D. Moore, 19 November 1973.

Type Locality. Cumpleaños Tide Pool, on intertidal platform; Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Gulf of California, Mexico.
NUMBER 96 • 253

Etymology. Laurencia fenicalii is named for Bill 

Fenical (Professor William H. Fenical, Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California, San Diego), a long-time friend, 

research collaborator, fellow diver, and “Baja aficionado” and 

Chief-Scientist on our Gulf of California and Pacific Mexico ship 

expeditions on the R/V Dolphin and ORV Alpha Helix. This is in 

recognition of not only his contributions to our knowledge of the 

natural product chemistry of marine algae and marine chemical 

ecology, including numerous studies on Gulf of California macroalgae, but also his early and continued emphasis on the importance of critical taxonomic identifications and voucher specimens.

Remarks. Chemically, Laurencia fenicalii (Fenical 

and Norris, 1975: figs. 2, 3, as “L. sp. I”) is distinguished from L. 

iriei and L. aguilar-rosasorum by its predominant secondary natural products, chondriol and chondrin, and other sesquiterpenoid 

derivatives, including cycloeudesmene (Fenical and Sims, 1974; 

Fenical et al., 1974, as “Chondria oppositiclada”; Howard and 

Fenical, 1975; Howard et al., 1980a, as “Laurencia sp.”). (See 

also Remarks under Laurencia aguilar-rosasorum and L. iriei.)

Laurencia hancockii E. Y. Dawson

Laurencia hancockii E. Y. Dawson, 1944a:328, pl. 50: fig. 1 [part of type 

specimen]; 1961b:454; 1963b:452, pl. 149: fig. 1; Chávez-Barrear, 

1972b:269; Huerta-Múzquiz and Garza-Barrientos, 1975:9; Schnetter 

and Bula-Meyer, 1982:190, pl. 30: fig. H; Huerta-Múzquiz and 

Mendoza-González, 1985:54; Mendoza-González and Mateo-Cid, 

1985:30; Dreckmann et al., 1990:32, pl. 6: figs. 3, 4; Sentíes-G. et 

al., 1990:111, pl. 12; Mateo-Cid and Mendoza-González, 1992:22; 

Serviere-Zaragoza et al., 1993a:484; Stout and Dreckmann, 1993:17; 

Mendoza-González et al., 1994:109; Bula-Meyer, 1995:39; GonzálezGonzález et al., 1996:321; Mateo-Cid et al., 2000:67; HernándezHerrera et al., 2005:148; Serviere-Zaragoza et al., 2007:10.

Algae forming loose clumps, mostly 1.5–2.5 cm tall; erect, 

branched, nondistinct main axis, cylindrical, 300–500 μm in 

diameter, up to 600 μm in lowermost portions; sometimes attached to each other by rhizoidal outgrowths; attached below by 

rhizoids from lower portions of erect branches and by prostrate 

branched axes. Branching irregular, multifarious or often more 

or less unilateral on convex side of curving or arching branches; 

ultimate branchlets short, up to 3 mm long, contracted at base. 

Outer cortex in surface view of isodiametrical cells near apices. 

In transection, medulla of large colorless cells without lenticular 

thickenings. Cortex of 3–4 cell layers; surface smooth; outer cells 

not protruding, not in palisade arrangement, secondary pit connections present; inner cortical cells elongated.

Tetrasporangia 80–100 μm in diameter; abundant in upper 

portion of unmodified ultimate branchlets; parallel arrangement. 

Gametangial specimens not observed.

Habitat. On rocks and tidal platforms, in tide pools, 

and epiphytic on Sargassum and possibly other algae; mid to low 

intertidal.

Distribution. Gulf of California: Ensenada de San 

Francisco (near Puerto San Carlos); Bahía Agua Verde to Cabeza Ballena; Mazátlan, Sinaloa to Jalisco. Eastern Pacific: Baja 

California; Isla Socorro (Islas Revillagigedo); Colima to Guerrero; Isla Gorgona, Colombia.

Type Locality. Rocky low intertidal; Bahía Agua 

Verde, Baja California Sur, Gulf of California, Mexico.

Laurencia iriei J. N. Norris et Fenical, sp. nov.

FIGURE 124C

Laurencia pacifica sensu Dawson, 1963b:457 [in part; only among Gulf of 

California specimens; non Laurencia pacifica Kylin, 1941:42].

Laurencia sp. II of Fenical and Norris, 1975:106, figs. 2, 3; Fenical et al., 

1975:3983.

Laurencia iriei, nom. nud., sensu Howard and Fenical, 1978:4401; Fenical, 

1978:245; Erickson, 1983:195.

Latin Description. Thalli rubra surrexit fortissimi laxa, usque 10 cm, ramosis teretibus secures 0.7–1.0 mm 

diametro, irregulariter alterne ramosae, usque III ordinibus axium 

plerumque dense numerosis ramis lateral 300–500(–700) μm diametro, angustata basin; rami usque 4 rebranched ordines formandi 

corymbosa dense aggregati ramulis unusquisque de ramulus 250–

300 μm diametro ramulis ultimis minoribus, apices rotundatos, 

per filo infra holdfast discoidea, nunc prostratus inseruerunt posterius rami. Medulla cellulis hyalinis magna, lenticellis inspissato 

nulla. Cortical cells exteriores aspectu superficiali, sphaericae vel 

irregulariter elongatae angulis rotundatis, plerumque 20–50 μm 

longa, 15–20 μm latae, in transection, 20–30 μm longa, 30–50 

μm crassa; nexus-secunda lacum quidam observatur inter cortical cells exteriores. Subsperical tetrasporangiis, 85–105 μm longa, 

80–100 μm diametro in superiore parte ramulis ultimi; cystocarpiis et spermatangia clavatae. Distinguitur chemica L. fenicalii

et L. aguilar-rosasorum ceterum secunda per naturalia, iriedol, 

iriediol et irieols A-G, nova diterpenes brominated.

Algae rose to red; very lax; up to 10 cm tall; of branched 

terete axes, 700–1,000 μm in diameter, irregularly alternately 

branched; axes usually densely covered with numerous lateral 

branches 300–500(–700) μm in diameter, narrowed at base; 

branches multifariously rebranched up to 4 orders, forming dense 

clusters of corymbose branchlets; each branchlet about 250–300 

μm in diameter; ultimate branchlets smaller, with rounded apices; attached below by a discoid holdfast and sometimes secondarily by entangled prostrate branches. Medulla of large colorless 

cells; lenticular thickenings absent. Outer cortical cells in surface 

view, subspherical to irregularly elongated with rounded corners, 

mostly 20–50 μm long, 15–20 μm wide; in transection, 20–30 

μm tall, 30–50 μm wide; secondary pit connections observed between some outer cortical cells.

Tetrasporangia subspherical, 85–105 μm long, 80–100 μm 

in diameter; in upper portion of ultimate branchlets (JN-4286,

US Alg. Coll. microscope slide 5062). Cystocarps and spermatangia not observed.

Habitat. On tidal platforms, in crevices, and in tide 

pools; mid to low intertidal.

Distribution. Gulf of California: Puerto Peñasco 

and vicinity; Bahía Concepcíon.

Holotype. JN-4519 (US Alg. Coll.-217747); Coll. 

J. N. Norris and K. E. Bucher, 9 November 1973.
254 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Type Locality. Attached to sides of Cumpleaños 

Tide Pool, Playa Las Conchas (Playa Estación), Puerto Peñasco, 

Sonora, Gulf of California, Mexico.

Paratypes. Sonora: on tidal platform, vicinity of Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), Puerto 

Peñasco, Coll. W. Fenical and K. Robertson, 23 October 1973, JN4286 (tetrasporophyte), US Alg. Coll. microscope slide 5062.

Etymology. Laurencia iriei is named in honor of 

Toshi Irie (Professor Emeritus, Department of Chemistry, Faculty 

of Science, Hokkaido University, Sapporo, Japan) in recognition 

of his pioneering contributions to our knowledge of the natural 

product chemistry of marine algae of Japan and the western Pacific. Professor Irie, who is now deceased, was the “father” of 

Laurencia chemistry.

Remarks. Natural product chemistries that distinguish Laurencia iriei (see Fenical and Norris, 1975: figs. 2, 3, as 

“L. sp. II”) from L. fenicalii and L. aguilar-rosasorum are the 

predominant secondary metabolities, iriediol and irieols A–G, 

novel brominated diterpenes (Fenical, 1975, 1978; Fenical et al., 

1975; Howard and Fenical, 1978), and the dipterpenoid neoirieone (Howard et al., 1982). (See also Remarks under Laurencia aguilar-rosasorum and L. fenicalii.)

Laurencia johnstonii Setchell et N. L. Gardner

FIGURE 124D

Laurencia johnstonii Setchell et N. L. Gardner, 1924:764, pl. 52: fig. A, 

pl. 53; Dawson, 1944a:328; 1959a:36; 1963b:453, pl. 156: figs. 1, 

2; 1966a:30; Norris, 1973:17; Huerta-Múzquiz, 1978:338; HuertaMúzquiz and Mendoza-González, 1985:54; Mendoza-González and 

Mateo-Cid, 1985:30; Norris, 1985d:213; González-González et al., 

1996:232; Riosmena-Rodríguez et al., 1998:26; L. Aguilar-Rosas et al., 

2000:132; Cruz-Ayala et al., 2001:191; CONANP, 2002:139; PachecoRuíz and Zertuche-González, 2002:468; Mateo-Cid et al., 2006:57; 

Pacheco-Ruíz et al., 2008:212.

Laurencia obtusiuscula Setchell et N. L. Gardner, 1924:760, pl. 23: fig. 17, pl. 

55; Dawson, 1944a:327 [in part]; 1949c:244; 1959a:36. 

Algae usually 10–20 cm tall; bright green and dark green 

to greenish purple when fresh (upon drying, often very dark to 

blackish green); of 1 or more erect, cylindrical main axes up 

to 1.5 mm in diameter, abundantly, multifariously branched; 

branches mostly 500–1000 μm in diameter, usually crowded 

with branchlets; ultimate branchlets 300–400(–600) μm in diameter, somewhat constricted at base; attached below by a discoid 

holdfast and sometimes secondarily by stoloniferous prostrate 

branches. Outer cortex in surface view of isodiametrical cells 

near apices, below becoming elongated; not protruding, surface 

smooth. In transection: medulla of large colorless cells; lenticular thickenings, small in size, occasionally to frequently present 

in some, apparently lacking in others; cortex of 3–4 cells; outer 

cortical cells of surface layer not in palisade arrangement.

Tetrasporangia mostly about 70 μm in diameter; abundant 

in upper portion of elongated, subcylindrical ultimate branchlets. 

Cystocarps urceolate, sessile, 500–600 μm in diameter; usually 1–2 

on ultimate branchlets. Spermatangia in whorls on spermatangial 

branch of trichoblast terminating with a tear-shaped sterile cell 

(10–14 μm long by 6–8 μm in diameter); spermatangial branches 

among sterile long, branched trichoblasts (up to 600 μm long) 

within broad cup-shaped pit of ultimate branchlets clustered on 

upper branches (JN-4304, US Alg. Coll. microscope slide 5063). 

Habitat. On rocks; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Punta Palmilla; Bahía Topolobampo. Eastern Pacific: Punta 

Morro (vicinity of Ensenada), Baja California, to “Campito,” 

19.3 km east of Punta Eugenia (“San Eugenio”), on southern 

shore of Bahía Sebastián Vizcaíno, Baja California Sur. 

Type Locality. Isla San Marcos (southeast of Santa 

Rosalía), Baja California Sur, Gulf of California, Mexico.

Remarks. Studies of the natural product chemistry 

of Laurencia johnstonii resulted in two halogenated sesquiterpenes being described (Fenical, 1975), johnstonol (Sims et al., 

1972) and prepacifenol epoxide (Faulkner et al., 1974). Two 

others, the cyclolauranes laurinterol and debromolaurinterol, 

which were described by Irie et al. (1970, as Laurencia intermedia Yamada, 1931) from the Japanese Palisada intermedia (Yamada) K. W. Nam (2007), have been also reported in Laurencia 

johnstonii (Erickson, 1983).

The red alga hemiparasite Erythrocystis saccata (J. Agardh) 

P. C. Silva (1952), although not observed in the northern Gulf of 

California, has been reported in the southern Gulf on L. johnstonii from Cabeza Ballena (Dawson, 1963b:441, pl.156: fig. 1). 

Laurencia lajolla E. Y. Dawson

Laurencia lajolla E. Y. Dawson, 1958:77, pl. 24: fig. 12; 1963b:455, pl. 

154: fig. 2; 1966a:31; Abbott and Hollenberg, 1976:731, fig. 682; 

Huerta-Múzquiz and Mendoza-González, 1985:54; MendozaGonzález and Mateo-Cid, 1986:425; Stewart, 1991:159; León-Tejera 

et al., 1993:200; Mateo-Cid et al., 1993:49; Mateo-Cid and MendozaGonzález, 1994b:42; Mendoza-González et al., 1994:109; GonzálezGonzález et al., 1996:232; Mateo-Cid et al., 2000:67; L. Aguilar-Rosas 

et al., 2000:132; Fernández-García et al., 2011:62. 

Algae small, dense, dark red clumps, often forming spreading turfs; of erect terete branched axes, up to 3 cm tall; primary 

axes sparse with branches, up to 1.5 cm long, that bear short 

branchlets in upper portions, (600–)700–850 μm in diameter; 

above a complex entangled system of prostrate, basal branches 

that attach at several places to substratum by small discs. Cortical cells not in a palisade layer; not projecting terminally; medullary cells without lenticular thickenings.

Tetrasporangia within simple, unmodified, short ultimate 

branchlets. Cystocarps and spermatangia not known. 

Habitat. On rocks and tidal platform; mid to low 

intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Isla Bargo, Bahía Concepción; Punta Arena to Cabo Pulmo; 

Mazátlan. Eastern Pacific: La Jolla (southern California) to Laguna Ojo de Liebre (Scammon’s Lagoon); Todos Santos, Baja 

California Sur; Oaxaca; El Salvador.

Type Locality. Growing among coralline algal turf 

on reef flat, below the north end of Neptune Place, Wind-and-Sea 

Beach, La Jolla, San Diego County, southern California, USA.
NUMBER 96 • 255

Remarks. Laurencia lajolla is not a well-known species. The collection of reproductive thalli and morphological and 

molecular DNA testing will help elucidate its taxonomic status. 

Dawson (1963b) also suggested some of the Laurencia collected 

from Puerto Escondido may also be L. lajolla. 

Excluded Species:

Laurencia pacifica Kylin

Laurencia pacifica sensu Dawson, 1963b:457 [in part: only Gulf of California specimens; non Laurencia pacifica Kylin, 1941:42].

Remarks. Studies have shown that the Pacific Coast 

Laurencia pacifica Kylin is a distinct species (Fenical and Norris, 

1975; Howard et al., 1980b). Those in the northern Gulf of California identified as “L. pacifica” following Dawson’s (1963b) 

broadly defined species concept are not L. pacifica Kylin but are 

actually three different species that are described herein as new 

species, L. aguilar-rosasorum, L. fenicalii, and L. iriei. Each of 

these species has its own unique natural product chemistries and 

morphologies, which are chemically and morphologically distinct from L. pacifica Kylin (lectotype locality: La Jolla, California; Smith, 1944). 

Chondrophycus (J. Tokida et Y. Saito) 

Garbary et J. Harper 

Chondrophycus (J. Tokida et Y. Saito) Garbary et J. Harper, 1998:194.

Laurencia subgen. Chondrophycus J. Tokida et Y. Saito in Saito, 1967:72.

Algae are erect, terete to strongly compressed, radially or 

distichously branched up to five orders, and attached by a discoid holdfast or stoloniferous branches. The apices of ultimate 

branchlets have depressed pits with numerous inconspicuous 

trichoblasts. Structurally, there is a central axial filament that 

bears the apical trichoblasts. Each vegetative axial segment has 

two pericentral cells, with the first pericentral cell developing lateral to the trichoblast (seen only near apical cell). However as the 

axis continues to develop, this soon becomes obscured and axes 

appear pseudoparenchymatous in structure. Inner cortical cells 

are ovoid and comparatively large. Medullary cells are without 

lenticular thickenings, and may or may not have internal rhizoids 

among them (Nam, 2011). The outer pigmented epidermal cells 

are smaller, with a single nucleus or multiple nuclei and mostly 

without secondary pit connections between them. Epidermal and 

cortical cells and trichoblasts are without corps en cerise. 

Tetrasporangial axial segments have 2 sterile pericentral cells 

(first and second pericentral cells are sterile), and additional fertile pericentral cells are produced that develop tetrasporangia in 

right-angle arrangement. Gametophytes are dioecious. Procarps 

developed in segments of five pericentral cells are a four-celled 

carpogonial branch and a basal sterile group of cells developed 

on the basal cell of trichoblasts. Cystocarps, with an ostiolate 

pericarp, are sessile and borne laterally on branches; internally, 

there is a basal fusion cell and branched gonimoblast that produces terminal carposporangia. Spermatangial branches are produced within cup-shaped pits from two laterals on the suprabasal 

cell of a trichoblast that remains partly sterile. Spermatangia are 

in lateral whorls around spermatangial branches that terminate 

with a large, sterile globose cell. 

Remarks. Garbary and Harper (1998), in recognizing Chondrophycus as a distinct genus, noted that there is a delay 

in the formation of auxiliary cells after presumed fertilization 

(Nam and Sohn, 1994) and that the larger spermatangia (greater 

than 10 μm long) may also be useful diagnostic characters. 

There is one species of Chondrophycus reported in the 

northern Gulf of California.

Chondrophycus glanduliferus (Kützing) Lipkin et P. C. Silva

Chondria glandulifera Kützing, 1845:329.

Chondrophycus glanduliferus (Kützing) Lipkin et P. C. Silva, 2002:35.

Laurencia glandulifera (Kützing) Kützing, 1849:855; Abbott, 1999:386, pl. 

112C,D; Mateo-Cid et al., 2006:57.

Chondria obtusa var. paniculata C. Agardh, 1822:342.

Laurencia paniculata sensu Saito, 1969b:158; Mendoza-González and 

Mateo-Cid, 1986:425; McDermid, 1988b:236, fig. 21 [non Laurencia paniculata Kützing, 1849:855; non L. paniculata (C. Agardh) 

J. Agardh, 1852b:755, nom illeg.].

Algae of several axes, up to 12 cm tall; arising from a discoid holdfast. Primary axes divided 2–3 times; lower portions 

bare; upper portions branched up to 4 orders, uppermost dense 

with small alternate to opposite short lateral branchlets. Medullary cells with thick cell walls (evident in older thalli), but without lenticular thickenings. Outer cortical cells radially elongate 

(description after Abbott, 1999).

Reproduction not described for Gulf of California specimens (Mateo-Cid et al., 2006). 

Habitat. Intertidal.

Distribution. Gulf of California: Puerto Peñasco; 

Isla Tiburón (Islas de la Cintura). Central Pacific: Hawaiian Islands. Western Pacific: Korea; Hong Kong.

Type Locality. Trieste, Gulf of Trieste, Adriatic 

Sea, northeastern Italy.

Remarks. The report of Chondrophycus glanduliferus in the upper Gulf of California is based on the record 

of Mateo-Cid et al. (2006) and from Isla Tiburon (MendozaGonzález and Mateo-Cid, 1986, as “Laurencia paniculata”). 

Since I have not seen their specimens, the description is based 

on Abbott (1999). Laurencia paniculata (C. Agardh) J. Agardh 

(1852b) has been considered conspecific with C. glanduliferus

(e.g., Abbott, 1999; John et al., 2004). (Note that this is a different species than Laurencia paniculata Kützing (1849), which is 

recognized to be a Palisada herein.) The Puerto Peñasco C. glanduliferus (Mateo-Cid et al., 2006) should be compared with type 

locality C. glanduliferus of the Adriatic Sea and the northern 

Gulf Palisada paniculata and P. pedrochei to elucidate their 

relationships.

Osmundea Stackhouse

Osmundea Stackhouse, 1809:56, 79; Nam et al., 1994:384.

Thalli of the Gulf of California species are usually compressed to flattened, and branching is distichous, rarely radial. 
256 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Ultimate branchlets with apical pit or depression with a tuft of 

inconspicuous, deciduous trichoblasts. The apical cell is always 

sunken in the apical pit of branchlets, and the central axial filament with its 2 pericentral cells per axial cell (vegetative segment), can be distinguished only near the apical cell, being 

obscured below by the formation of an extensive cortex. Secondary pit connections between epidermal cells are absent in 

some or, if present, are variable, frequent to rare. Corps en cerise

(gland cells) are apparently absent in the known species.

Tetrasporangia develop from random, outer cortical (epidermal) cells with longitudinal cover cells in parallel arrangement. 

Female gametophytes form 5 pericentral cells in the procarpbearing segment of the female trichoblast. Cystocarps lack or 

may have ostioles that are usually protuberant. Spermatangia 

develop on filaments formed by apical and epidermal cells (“filament type”) that either lack or may terminate with 1 to a cluster of enlarged sterile cells. Spermatangial filaments develop in 

urn-shaped (pocket) spermatangial depressions (North Pacific 

species); in cup-shaped spermatangial depressions (European 

species); or rarely in slightly sunken cup-shaped depressions. 

Remarks. Laurencia sect. Pinnatifidae J. Agardh 

(1876) as defined by Saito (1982) was later emended and merged 

into L. subgen. Saitoa G. Furnari et Serio, 1993, nom. illeg., a 

group now recognized to contain many members of Osmundea 

(McIvor et al., 2002). Although spermatangial development in 

urn-shaped receptacles (pocket; depressions) was reported to be 

only in the genus Osmundea (Nam et al., 1994), further studies 

showed that not all of the species of Osmundea have this character 

(Garbary and Harper, 1998; Serio et al., 1999; Nam et al., 2000; 

McIvor et al., 2002). Comparative morphological and molecular phylogenetic studies found three clades from three different 

geographical regions (McIvor et al., 2002). The North American 

(California) clade had a fixed, urn-shaped spermatangial receptacle, and the number of secondary pit connections in the surface 

cortical cells was variable. In contrast, the two European clades 

showed character reversals: spermatangial receptacles were cupshaped in both, and the two were distinguishable by the presence 

or absence of secondary pit connections between epidermal cells. 

However, McIvor et al. (2002) also question the sole use of morphological characters in infrageneric subdivision of Osmundea. 

Agar has been found to be a component in at least one of the 

species, Osmundea pinnatifida (Hudson) Stackhouse (1809), by 

Bowker and Turvey (1968a, 1968b, as “Laurencia pinnatifida”). 

It is not known at this time whether any of the species from the 

northern Gulf of California produce agar. Apparently the species of Osmundea have not evolved antiherbivore secondary metabolites (Hommersand, 1990; McIvor et al., 2002) as found in 

Laurencia (e.g., Fenical, 1975; Norris and Fenical, 1982, 1985).

Species of Osmundea mostly occur in temperate waters and 

are known only on the coasts of Pacific North America and the 

Atlantic and Mediterranean coasts of Europe (Serio et al., 1999, 

Nam et al., 2000; McIvor et al., 2002). A tropical Pacific Mexico 

species, O. purepecha Sentíes, Mendoza-González et Mateo-Cid, 

described from Michoacán (Sentíes et al., 2014) is distinguished 

from those in the Gulf by its unique stoloniferous holdfast and 

genetic analyses.

There are three species of Osmundea occurring in the northern Gulf of California.

KEY TO THE SPECIES OF OSMUNDEA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thallus usually large, 5–10 cm tall, with relatively wide flat branches, mostly 3–4 mm wide, with short, blunt subterete 

branchlets on flattened distal portions of branches; initial branching distichous to subdistichous, alternate; attached by a 

small discoid holdfast; medullary cells without lenticular thickenings . . . . . . . . . . . . . . . . . . . . . . . . . . . O. estebaniana

1b. Thalli comparatively shorter, mostly less than 4.0(–9) cm tall; branching open or dense, flat branches 1–4 mm wide; 

medullary cells with or without lenticular thickenings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Thalli epiphytic, somewhat lax; flat branches up to 2(–4) mm wide; branching distichous throughout, irregularly alternatepinnate; medullary cells without or sometimes with lenticular thickenings (especially in large specimens) . . . . O. sinicola

2b. Thalli growing on rocks (not epiphytic), rigid, crisp, compact; flat branches wider, 3–4 mm in width; branching alternately distichous, obscured by dense crowding of branches; attached by spreading basal crust; medullary cells without 

lenticular thickenings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . O. blinksii

Osmundea blinksii (Hollenberg et I. A. Abbott) K. W. Nam

Laurencia blinksii Hollenberg et I. A. Abbott, 1965:1186, pl. 2: fig. 5; Hollenberg and Abbott, 1966:117, fig. 52; Smith, 1969:727, fig. 52; Saito, 

1969a:87; Abbott and Hollenberg, 1976:728, fig. 678; RiosmenaRodríguez et al., 1998:26.

Osmundea blinksii (Hollenberg et I. A. Abbott) K. W. Nam in Nam, Maggs 

and Garbary, 1994:393; Pacheco-Ruíz et al., 2008:213.

Algae erect, forming dense, expanding tufts, 4–7 cm tall and 

nearly as wide; of cartilaginous, crisp flattened axes (except near 

the base), more or less alternately distichously branched (distichous branching becoming obscure by divergent growth and 

crowding of branches); branches lanceolate–conical, pyramidal 

in outline, 3–4 mm in width (see Abbott and Hollenberg, 1976: 

fig. 678); axes arising from spreading basal crust, about 3–4 cm 

wide. Medulla of large cells, 300–400 μm long, 60–150 μm in 

diameter, without lenticular thickenings. Cortex in surface view 

of pigmented cortical cells, 25–45 μm long, 13–15 μm wide; 

cortical cells in transection, slightly radially elongated to deeply 

anticlinal in smaller branches, 15–30 μm deep; secondary pit 

connections between epidermal cells very rare. Epidermal cells 

nonpalisade in arrangement; secondary pit connections between 

epidermal cells very rare.

Reproductive branches irregularly lobed or divided. Tetrasporangial branches fungiform or alternately branched; tetra-
NUMBER 96 • 257

sporangia in parallel arrangement (see Saito, 1969a: fig. 4A). 

Cystocarps unknown. Male gametophyte with spermatangial 

filaments in deep ovoid cavities (urn-shaped); following formation of initial spermatangial cavity, subsequent cavities formed 

upwards; more or less irregularly arranged on short subultimate 

branchlets (see Saito, 1969a: fig. 5A, B).

Habitat. On rocks; low intertidal.

Distribution. Gulf of California: Bahía de Los 

Ángeles. Eastern Pacific: central California.

Type Locality. Exposed rocky shores; just south of 

Malpaso Creek, Monterey County, central California, USA.

Remarks. A California species, Osmundea blinksii has also been reported in the northern Gulf by RiosmenaRodríguez et al. (1998). Since I have not seen their material, the 

description is based on Abbott and Hollenberg (1976) and Saito 

(1969a), both as Laurencia blinksii.

Osmundea estebaniana (Setchell et N. L. Gardner) J. N. 

Norris, comb. nov.

FIGURE 125A,B

Laurencia estebaniana Setchell et N. L. Gardner, 1924:763, pl. 24: fig. 34, 

pl. 45: fig. a [type specimen]; Dawson, 1944a:328; 1963b:451, pl. 

FIGURE 125. Species of Osmundea. A, B. Osmundea estebaniana: A. Habit (JN-5832, US Alg. Coll.-160119). B. Habit (JN-5273, US Alg. 

Coll.-160111). C. Osmundea sinicola: Habit of large robust specimen (D. Bean, s.n., US Alg. Coll.-30106).
258 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

146: fig. 2; Norris, 1973:17; Serviere-Zaragoza et al., 1993a:484; 

González-González et al., 1996:232; CONANP, 2002:139; 

Pacheco-Ruíz and Zertuche-González, 2002:468; Pacheco-Ruíz et 

al., 2008:212. 

Algae up to 10 cm tall; of distinctly compressed axes, 2.0–

4.0 mm wide, branched up to 4(–5) orders; attached by small 

discoid holdfast. Branching distichous to subdistichous, mostly 

alternately from primary and secondary axes; later, shorter blunt 

subterete branchlets may develop from flattened surfaces of distal branches. Medullary cells large, colorless, without lenticular 

thickenings. Cortical cells, isodiametrical, 12–25 μm in diameter. 

Corps en cerise absent.

Ultimate branchlets with reproductive structures; short, subcylindrical to rounded (wart-like), few to several subdistichous to 

subverticillately arranged. Tetrasporangia in short nearly cylindrical branchlets. Cystocarps on short nearly cylindrical branchlets. Spermatangial branchlets turbinate; spermatangia in dense, 

short clusters, surrounding simple spermatangial filament that 

terminates with a distinctive, large, subglobose sterile cell, 20–25 

μm long, 16–20 μm in diameter (see Setchell and Gardner, 1924: 

pl. 24: fig. 34, “filament type”); spermatia 2–3 μm in diameter.

Habitat. On rocks; low intertidal to shallow subtidal.

Distribution. Gulf of California: Bahía Agua 

Dulce, Isla Tiburón and Isla San Esteban (Islas de la Cintura); 

Isla Coronado (Isla Smith) to Bahía San Francisquito; Bahía de 

Loreto; Bahía de Banderas, Nayarit-Jalisco. 

Type Locality. On rocks; Isla San Esteban, Islas de 

la Cintura, Gulf of California, Mexico. 

Remarks. A Gulf of California endemic, the largest 

specimens of Osmundea estebaniana have been found in Las Islas 

de la Cintura. The slender, subcylindrical southern Gulf specimens referred to “O. estebaniana” from Puerto Escondido by 

Dawson (1963b, as “L. estebaniana”) may be another species.

Osmundea sinicola (Setchell et N. L. Gardner) K. W. Nam

FIGURE 125C

Laurencia sinicola Setchell et N. L. Gardner, 1924:764, pl. 29: figs. 65, 66, pl. 

50: fig. a [type specimens]; Dawson, 1944a:328; 1959a:36; 1961b:455; 

1963b:461, pl. 146: fig. 1, pl. 166: figs.1, 2; 1966a:31; Abbott and Hollenberg, 1976:732, fig. 685; Huerta-Múzquiz and Mendoza-González, 

1985:54; Mendoza-González and Mateo-Cid, 1985:30; MendozaGonzález and Mateo-Cid, 1986:425; Sánchez-Rodríguez et al., 1989:47; 

R. Aguilar-Rosas et al., 1990:126; R. Aguilar-Rosas and MachadoGalindo, 1990:188 ; Stewart, 1991:160; Mateo-Cid et al., 1993:49; 

R. Aguilar-Rosas and Aguilar-Rosas, 1994:525; González-González et 

al., 1996:234; Riosmena-Rodríguez et al., 1998:26; Cruz-Ayala et al., 

2001:191; Pacheco-Ruíz and Zertuche-González, 2002:469. 

Osmundea sinicola (Setchell et N. L. Gardner) K. W. Nam in Nam et al., 

1994:393; L. Aguilar-Rosas et al., 2000:132; Mateo-Cid et al., 2006:57; 

Serviere-Zaragoza et al., 2007:11; Pacheco-Ruíz et al., 2008:213; 

Castañeda-Fernández de Lara et al., 2010:200; Fernández-García et al., 

2011:62.

Laurencia scrippsensis E. Y. Dawson, 1944b:234, pl. 26: fig. 3, pl. 27: figs. 

1, 2, 4; 1945d:68; 1951:53; 1952:431; 1961b:454; González-González 

et al., 1996:234. 

Algae epiphytic; caespitose, compressed, dark reddish 

brown, (1.0–)4.0–9.0 cm high, 1.0–2.0 (–4.0) mm wide, and 

400–500 μm thick; branching irregularly alternate-pinnate in 1 

plane (tetrasporophytes more regularly pinnate). Secondary pit 

connections between surface cortical cells rare. Medullary cells 

70–90 μm in diameter, thin walled; lenticular thickenings absent, 

or rare to abundant (mostly seen in larger thalli; generally absent 

in smaller ones). Cortical cells 20–30(–50) μm in diameter. Arrangement of epidermal cells nonpalisade.

Tetrasporangia in short, simple to digitate branchlets. Cystocarps ovoid to hemispherical, 600–800 μm in diameter; scattered, on margins and surfaces of irregularly branched ultimate 

branchlets. Spermatangial filaments within urn-shaped receptacles; receptacles solitary or in series; embedded in subterminal 

portions of ultimate branchlets.

Habitat. Usually epiphytic on other algae; mid to 

low intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía San José del Cabo. Eastern Pacific: Santa Cruz Island 

(California Channel Islands); Islas Todos Santos (Baja California); La Jolla, southern California to Isla Magdalena (Bahía 

Magdalena), Baja California Sur; Isla San Benedicto (Islas Revillagigedo); Panama.

Type Locality. Epiphytic on Sargassum; Eureka 

(vicinity of La Paz: 23°36′N, 109°36′W), Baja California Sur, 

Gulf of California, Mexico.

Remarks. Dawson (1963a, as Laurencia sinicola) 

observed that during fall–winter, the smaller thalli of Osmundea sinicola had thin-walled medullary cells without lenticular 

thickenings, whereas during summer the thalli he referred to this 

species were larger and had developed abundant lenticular thickenings. Season and growth may play a role in the development 

of lenticular thickenings, at least for this species. The range of 

thallus size and variability of anatomical characters suggests this 

is either a single, broadly defined species or possibly a complex 

of more than one species.

Palisada K. W. Nam

Palisada K. W. Nam, 2007:53.

Palisada K. W. Nam, 2006:693, nom. illeg.

Laurencia sect. Palisadae Yamada, 1931:190.

Chondrophycus subgen. Palisada (Yamada) K. W. Nam, 1999:467.

Algae are mostly terete to subterete. Ultimate branchlets 

have an apical pit or depression with a tuft of inconspicuous 

trichoblasts. The apical cell is also sunken within the apical 

pit, and the central axis can only be seen near the apical cell 

(becoming obscured by formation of an extensive cortex). The 

vegetative axial segments have two pericentral cells, with the 

first pericentral cell developed underneath the basal cell of the 

trichoblast. The cortical (epidermal) cells, as seen in transection, 

are in a palisade-like arrangement (most evident in branches), 

with secondary pit connections mostly absent between adjacent 

cells. Medullary cell walls can be wide, but are without lenticular 

thickenings. Corps en cerise are apparently absent or rare.
NUMBER 96 • 259

Tetrasporangia develop on specific pericentral cells; the first 

pericentral cell remains sterile and the second pericentral cell is 

fertile, and an additional third pericentral cell (and in some species a fourth) is issued that also develop tetrasporangia. Procarps 

are borne on fertile segments of four or five pericentral cells on 

a female trichoblast. Auxiliary cells are normally developed after 

presumed fertilization. Spermatangial branches are produced 

from one of two laterals on the suprabasal cells of the trichoblasts, “trichoblast-type development” (reproduction after Nam, 

2006, 2007, 2011; Cassano et al., 2009).

Remarks. Agar has been reported in the cell wall 

polysaccharides from a few of the species, e. g., Palisada perforata (Bory Saint-Vincent) K. W. Nam (2007) in Tanzania 

(Mshigeni and Nzalalila, 1977, as “Laurencia papillosa”), and 

P. flagellifera (J. Agardh) K. W. Nam (2007) from Brazil (Ferreira 

et al., 2012). The polysaccharide chemistries of species from the 

northern Gulf of California have not yet been investigated. 

Palisada perforata (Bory de Saint-Vincent) K. W. Nam 

(2007) has been reported in the southern Gulf from Bahía de La 

Paz (Cruz-Ayala et al., 2001, as “Laurencia papillosa”). These 

Gulf specimens should be reexamined and compared to Palisada pedochei and P. papillosa (C. Agardh) K. W. Nam (2007, 

2011).

Currently, two species of Palisada are recognized in the 

northern Gulf of California. In the field, Palisada paniculata and

P. pedrochei are the coarsest, widest in diameter, and sometimes 

the largest among the cylindrical species of the tribe Laurencieae 

known in the Gulf of California.

KEY TO THE SPECIES OF PALISADA IN THE NORTHERN GULF OF CALIFORNIA

1a. Ultimate branchlets not dense, but loosely disposed, mostly peg-like (some may be partly wart-like) .. . . . Palisada paniculata

1b. All branches densely covered with very short, wart-like ultimate branchlets. . . . . . . . . . . . . . . . . . . Palisada pedrochei

Palisada paniculata (Kützing) J. N. Norris, comb. nov.

FIGURES 8E, 126A–D

Laurencia paniculata Kützing, 1849:855; Kützing, 1865:22, pl. 63: figs. a-b 

[illustrations designated as lectotype herein; non Laurencia paniculata

(C. Agardh) J. Agardh, 1852b:755; basionym: Chondria obtusa var.

paniculata C. Agardh, 1822:343; Yamada, 1931:192, pl. 3a (type specimen); see Remarks below]. 

Laurencia paniculata sensu Howe, 1911:508; Setchell and Gardner, 

1924:762; Dawson, 1944a:326; 1963b:459, pl. 145: fig. 5, pl. 155: figs. 

1, 2; 1966a:31; Saito, 1969b:158; Norris, 1973:17; Huerta-Múzquiz, 

1978:337; Stewart and Stewart, 1984:147; Mendoza-González and 

Mateo-Cid, 1986:425; González-González et al., 1996:233; CONANP, 

2002:138; Pacheco-Ruíz and Zertuche-González, 2002:469; PachecoRuíz et al., 2008:213 [non Laurencia paniculata (C. Agardh) J. Agardh, 

1852b:755, nom. illeg. (see Furnari et al., 1999:44); =Chondrophycus 

paniculatus (C. Agardh) G. Furnari in Boisset et al., 2000:393, nom. 

illeg., which is now Palisada thuyoides (Kützing) Cassano, SentíesGranados, Gil-Rodriguez et M. T. Fujii (in Cassano et al., 2009:95); 

basionym: Laurencia thuyoides Kützing, 1865:26]. 

Algae up to 12 cm tall, somewhat coarse and bushy, usually 

dark reddish; of a single main axis, often abundantly branched 

up to 5 orders; axis and branches, cylindrical, up to 1.5 mm 

in diameter in upper portions and up to 2.5 mm in diameter 

in lower portions; secondary branches tending to percurrent 

and pyramidal; attached by a coarse, discoid holdfast. Branch 

intervals somewhat variable, usually 3–10 mm in lower thallus; branches with wart-like to peg-like ultimate branchlets, not 

dense or crowded, giving an open appearance. Medulla of larger 

cells, without lenticular thickenings. In transaction, epidermal 

cells are rectangular, 25–35 μm long and about 10–16 μm in 

diameter, in palisade-like arrangement.

Tetrasporangia embedded in upper portion of short, turbinate branchlets. Cystocarps urceolate or hemispherical, 600–800 

μm in diameter on ultimate branchlets. Spermatangia not seen in 

Gulf of California specimens. 

Habitat. On rocks and tidal platforms and in tide 

pools; mid to low intertidal.

Distribution. Gulf of California: Isla San Jorge 

(Bird Island); Puerto Peñasco to Guaymas; Puerto Refugio, Isla 

Ángel de la Guarda; Bahía de Los Ángeles to Cabeza Ballena. 

Eastern Pacific: Isla Guadalupe (off Baja California); Islas San 

Benito (west of Isla Cedros). 

Type Locality. Syntype localities: in Adriatic and 

Mediterranean Seas (Kützing, 1849:855); lectotype locality: 

“mari mediterraneo” (Kützing, 1865:22).

Remarks. Morphologically, Laurencia paniculata

Kützing (1849) has the characteristics of Palisada, and the new 

combination is proposed. In the absence of a known type specimen, the illustration of Kützing (1865: pl. 63: figs. a, b; herein 

Figure 126A) of Laurencia paniculata Kützing (1849) are selected as the lectotype. 

The epithet “paniculata” has been used for more than one 

taxa. First, the name was used to describe a variety, Chondria 

obtusa var. paniculata C. Agardh (1822), which was then transferred to Laurencia, as L. paniculata (C. Agardh) J. Agardh 

(1852b); that name and those authors have long been used in 

the literature (e.g., De Toni, 1903; Yamada, 1931; Dawson, 

1963b; McDermid, 1988b; Abbott, 1999, as Laurencia glandulifera). Unfortunately, as noted by Furnari et al. (1999), 

J. Agardh’s (1852b) use of that name created a later homonym 

of Laurencia paniculata Kützing (1849). Furnari et al. (1999) 

also suggested L. paniculata Kützing (1849) may taxonomically 

be conspecific with Osmundea ramosissima (Oeder) Athanasiadis (1996b; basionym: Fucus ramosissimus Oeder, 1766), and 

Boisset et al. (2000) noted that according to Ardissone (1883), 

L. paniculata Kützing may be conspecific with “Laurencia pinnatifida” (probably L. pinnatifida (Hudson) J. V. Lamouroux 

(1813); basionym: Fucus pinnatifidus Hudson, 1762, which is 

now Osmundea pinnatifida (Hudson) Stackhouse, 1809). Thus, 

there is confusion on its taxonomic status, and it is suggested 
260 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

that L. paniculata Kützing (1849) sensu stricto be based on its 

lectotype illustrations (Figure 126A) until molecular analyses on 

its type locality material can be performed to compare it with 

other taxa.

Another similar-looking species, Laurencia thuyoides Kützing (1865:26, pl. 74: figs. a, b) was considered to be conspecific 

with “L. paniculata (C. Agardh) J. Agardh” by Yamada (1931), 

a conclusion followed by Boisset et al. (2000, as Chondrophycus 

paniculatus (C. Agardh) G. Furnari). Since that combination 

was illegitimate, Furnari et al. (2001) subsequently proposed 

another name for the taxon, C. thuyoides (Kützing) G. Furnari (basionym: L. thuyoides Kützing, 1856). More recently, it 

FIGURE 126. Species of Palisada: A–D. Palisada paniculata: A. Lectotype illustration selected of Laurencia paniculata Kützing (from Kützing, 1865: pl. 63a,b). B. Habit of a small part of a slender form (from Dawson, 1963b: pl. 145: fig. 5). C, D. Habits (JN-5006, US Alg. Coll.-

160223).E. Palisada pedrochei: Habit (holotype, JN-5879, US Alg. Coll.-160250).
NUMBER 96 • 261

was transferred to Palisada, as P. thuyoides (Kützing) Cassano, 

Sentíes-Granados, Gil-Rodriguez et M. T. Fujii (in Cassano et 

al., 2009; =P. thuyoides (Kützing) Serio, Cormaci, G. Furnari et 

Boisset, 2010:14, nom. illeg.).

The northern Gulf of California specimens referred to 

Palisada paniculata (Kützing) J. N. Norris need to be tested in 

comparative molecular studies with L. paniculata Kützing (lectotype locality: Mediterranean Sea), the Adriatic “L. paniculata 

(C. Agardh) J. Agardh” (type locality: Trieste, Italy), L. pinnatifida (Hudson) J. V. Lamouroux (type locality: Harwick, Essex, 

England), Chondrophycus glanduliferus (Kützing) Lipkin et P. C. 

Silva (type locality: Trieste, Italy), the South Pacific Palisada 

thuyoides (type locality: New Caledonia), and the eastern and 

western Atlantic P. thuyoides (Cassano et al., 2009) to further 

elucidate the relationships and taxonomic status of these geographically widespread but somewhat similarly looking species. 

Palisada pedrochei J. N. Norris, sp. nov.

FIGURE 126E

Laurencia papillosa var. pacifica Setchell et N. L. Gardner, 1924:765, pl. 23: 

fig. 18, pl. 24: fig. 34, pl. 43a,b, pl. 54 [type specimen: Marchant-38, CAS, 

now UC]; Dawson, 1944a:327; 1959a:36; 1961b:454; 1963b:460, pl. 

166: fig. 3; Norris, 1973:16; Stewart and Stewart, 1984:147; HuertaMúzquiz and Mendoza-González, 1985:54; Mendoza-González and 

Mateo-Cid, 1985:30; Sánchez-Rodríguez et al., 1989:47; Mateo-Cid 

and Mendoza-González, 1992:22; Mendoza-González and MateoCid, 1992:20; Serviere-Zaragoza et al., 1993a:484; Mateo-Cid and 

Mendoza-González, 1994b:42; González-González et al., 1996:233; 

Anaya-Reyna and Riosmena-Rodríguez, 1996:864, tbl. 1; RiosmenaRodríguez et al., 1998:26; L. Aguilar-Rosas et al., 2000:132; CONANP, 

2002:139; Pacheco-Ruíz and Zertuche-González, 2002:469; MateoCid et al., 2006:57; Serviere-Zaragoza et al., 2007:10; Pacheco-Ruíz 

et al., 2008:213. 

Latin Description. Thalli ad 13 cm altus; plus 

minus forma pyramidalis, purpureo brunneo ad atro-rubio colore, axes principales teres percurrentes, ramosae 3–4 ad ordines, 

ramulis lateralis primam ad 6.5 cm longis, 1.5 ad 2.5 mm diametro, inter breviores aliquot quae ramis plerumque dense ramosae brevibus ramulis ultimis ut turbinata. Cortex in transection 

de radialiter rectangulae cells, ordinate in vallumque-amolayer; 

cortical cells, aspectu superficiali, polygoniis, tenui-membranis, 

18–22 μm in diametro. Sine cellulis lenticellis medullare inspissato. Tetrasporangial sphaerica circa 100 μm diametro infra 

circa ramulis ultimi depression terminali. Cystocarpiis non describet. Verticillis in spermatangia in axial fiament cessat in uno 

terminari, large cell pyriformis.

Algae erect, up to 13 cm tall, somewhat pyramidal in shape; 

dark red, brownish to purplish (drying blackish brown); terete 

main axes percurrent, branched to 3–4 orders; with primary lateral branches up to 6.5 cm long, 1.5–2.5 mm in diameter, each 

with several shorter branches; covered, usually densely, with 

short, subspherical to turbinate, ultimate branchlets. In transection the outer cortical cells are elongated and rectangular, 

arranged in a palisade-like layer; cortical cells in surface view, 

polygonal, thin walled, 18–22 μm in diameter. Medullary cells 

without lenticular thickenings.

Tetrasporangia spherical, about 100 μm in diameter; within 

the ultimate branchlets around their apical depression. Cystocarps not observed. Spermatangia in whorls around dense spermatangial branches borne off one lateral of trichoblast, each 

spermatangial branch terminated by a single, large pyriform cell.

Habitat. On rocks, tidal platforms, and sides of tide 

pools; high to low intertidal. 

Distribution. Gulf of California: Puerto Peñasco 

to Bahía Kino (Sonora); El Coloradito (Baja California) to Punta 

Palmilla (Baja California Sur); Nayarit to Jalisco. Eastern Pacific: 

Bahía Magdalena to Todos Santos, Baja California Sur; Isla Clarión (Islas Revillagigedo). 

Holotype. JN-5879 (US Alg. Coll.-160250). 

Type Locality. On tidal platform; Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Gulf of California, Mexico.

Etymology. Palisada pedrochei is named for Francisco F. Pedroche (Rector de la Unidad Lerma and Professor, 

Departamento de Ciencias Ambientales, División de Ciencias 

Biológicas y de la Salud, Universidad Autónoma MetropolitanaLerma, Lerma de Villada, Mexico) in recognition of his continuing contributions to our knowledge of the marine algae of Pacific 

Mexico, including the Gulf of California. 

Remarks. Morphologically, Palisada pedrochei is 

the same as the variety Laurencia papillosa var. pacifica Setchell 

et N. L. Gardner (1924) described from Eureka (near La Paz, 

Baja California Sur) in the southern Gulf. Since there is no priority outside of rank (International Code of Botanical Nomenclature [ICBN]; McNeill et al., 2006; 2012), I chose to describe it 

as a new species to avoid any confusion that might be created 

by using the name “pacifica,” an epithet already used for both 

L. papillosa var. pacifica and L. pacifica Kylin (1941).

Specimens of Setchell and Gardner (1930, as “L. papillosa

var. pacifica”) from Isla Guadalupe (Pacific Baja California) appear to be a different species and need to be further studied.

Rhodomelaceae tribus Polysiphonieae

Rhodomelaceae tribus Polysiphonieae F. Schmitz, 1889:147.

Remarks. The tribe Polysiphonieae is represented by 

two of its genera in the northern Gulf of California.

Neosiphonia M.-S. Kim et I. K. Lee

Neosiphonia M.-S. Kim et I. K. Lee, 1999:272.

Algae composed of terete, polysiphonous axes and branches 

of 4–9 pericentral cells per segment that may be corticated or uncorticated and are attached at irregular intervals by mostly unicellular rhizoids cut off from basal pericentral cells or cortical cells 

by a cross wall. Branching is mostly alternate to several orders 

and sometimes profuse or dense. Branches and ultimate branchlets are basically similar to main axes and primary branches, 
262 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

and most develop exogenously but sometimes may be formed 

in connection with a trichoblast or rarely cicatrigenous (lateral 

branches originating from scar cells). Trichoblasts are colorless, 

slender, simple or forked filaments formed at regular intervals, 

1 per segment, and spirally arranged, most common near branch 

apices; deciduous, often leaving conspicuous scar cells. 

Tetrasporangia tetrahedrally divided; borne in spiral series, 

one per segment, developed on the second pericentral cell next 

to the basal cell of a trichoblast on indeterminate branches. Procarps bearing a 3-celled carpogonial branch. Cystocarps are subglobose to ovate, borne on a short pedicel, and scattered on the 

upper branches. Spermatangial branchlets (stichidia) develop on 

1 branch fork of a fertile trichoblast;cylindrical in shape, some 

may have 1(–2) short sterile cell(s) at tip. 

Remarks. In describing Neosiphonia, M.-S. Kim and 

Lee (1999) noted that the genus differs from the similar Polysiphonia in vegetative and reproductive characters. These have long 

been used by Hollenberg (e. g., 1942a, 1942b, 1944, 1961, 1968a, 

1968b; Abbott and Hollenberg, 1976; Hollenberg and Norris, 

1977) as species characters to distinguish taxa of a broadly defined Polysiphonia. As currently recognized, Neosiphonia has lateral branch initials and trichoblast initials produced on successive 

segments; determinate branches that develop from the main axes; 

attachment rhizoids are cut off from pericentral cell by a cross 

wall; trichoblasts are spirally arranged and usually abundant; tetrasporangia are in spiral series; carpogonial branch is three-celled; 

and spermatangia develop on one fork of a trichoblast. 

The relationship of Neosiphonia to another genus, Carradoriella P. C. Silva (in Silva et al., 1996a, generitype C. virgata (C. Agardh) P. C. Silva, a replacement name for Carradoria

Kylin, 1956 [non Carradoria C. Martius, 1833]) needs to be 

investigated. Although noting that Neosiphonia shares some 

generic characters with Polysiphonia sensu stricto, H.-G. Choi 

et al. (2001a) also suggested that Carradoriella, on the basis of 

their molecular analyses, may be the same as Neosiphonia or 

possibly a sister taxon. Until critical comparative morphological 

studies, particularly of reproductive structures, and further DNA 

genetic comparisons that include the respective generitypes are 

carried out, Neosiphonia is recognized herein.

Species of Neosiphonia are found growing as epiphytes 

on other algae or seagrasses, epizoic on sea turtles, or on rocks 

or other hard substrata. There are three species reported in the 

southern Gulf: Neosiphonia bajacali (Hollenberg) Mamoozadeh 

et Freshwater (2011; basionym: Polysiphonia bajacali Hollenberg, 1961) from Laguna Agiabampo (Ortega et al., 1987, as 

P. bajacali) and Jalisco (Hernández-Herrera et al., 2005, as P. bajacali); N. sphaerocarpa (Børgesen) M.-S. Kim et I. K. Lee (1999) 

from Nayarit (Sentíes-G., 1995, as P. sphaerocarpa; see also Remarks under N. savatieri); and N. beaudettei (Hollenberg) M.-S. 

Kim et I. A. Abbott (2006; basionym: Polysiphonia beaudettei

Hollenberg, 1961) from Bahía de La Paz (Huerta-Múzquiz and 

Mendoza-González, 1985, as P. beaudettei).

There are 11 species of Neosiphonia in the northern Gulf 

of California.

KEY TO THE SPECIES OF NEOSIPHONIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Polysiphonous filaments with 4 pericentral cells per segment; Neosiphonia sect. Neosiphonia. . . . . . . . . . . . . . . . . . . 2

1b. Polysiphonous filaments with 5 or more pericentral cells per segment; Neosiphonia sect. Multisiphonia. . . . . . . . . . . . 7 

2a. Branching dichotomous throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. masonii

2b. Branching subdichotomous (not strictly dichotomous) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Epizoic; only known growing on sea turtle carapace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. cheloniae

3b. Either epiphytic or saxicolous; not growing on sea turtles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Branches arising from a primary branch of a trichoblast (axillary to a trichoblast) . . . . . . . . . . . . . . . . N. flaccidissima

4b. Branches arising from an entire trichoblast primordium . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5a. Thalli mostly less than 2 cm high; epiphytic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. savatieri

5b. Thalli mostly more than 2 cm tall; usually not epiphytic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6a. Segments in main branches mostly shorter, not as long as diameter or sometimes as long as wide . . . . . . . . . N. simplex

6b. Segments in main branches longer than wide; mostly 1.5 times longer (or occasionally longer) than diameter . . . N. eastwoodae

7a. Pericentral cells 5 per segment; segments shorter in length than diameter . . . . . . . . . . . . . . . . . . . . . . . . . . N. concinna

7b. Pericentral cells 5 or more per segment; segments of similar length and diameter or longer . . . . . . . . . . . . . . . . . . . . . 8

8a. Pericentral cells 5–6 per segment; segments 1.5 times longer or more than diameter . . . . . . . . . . . . . . . . . N. johnstonii

8b. Pericentral cells 6 or more per segment; segments of similar length and diameter or slightly longer or up to about 2.0–4.0 

times longer than diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

9a. Thalli minute, up to 2 mm tall; prostrate axes and lower portion of erect branches mostly of 6 pericentral cells per segment; upward in erect portions the 6 pericentral cells divide to 12 pericentral cells per segment . . . . . . . . N. mexicana

9b. Thalli much larger, more than 1 cm tall; prostrate and erect axes and branches with similar number of pericentral cells, 

8 or more per segment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

10a. Thalli mostly less than 2 cm high; segments more or less equal in length and diameter to only slightly longer in length 

than diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . N. confusa

10b. Thalli usually much larger, up to 20 cm tall; segments 2.0–2.5(–4.0) times longer than diameter . . . . . . . N. paniculata
NUMBER 96 • 263

Neosiphonia M.-S. Kim et 

I. K. Lee sect. Neosiphonia

Members of Neosiphonia sect. Neosiphonia have four pericentral cells per polysiphonous segment, thus differing from 

members of N. sect. Multisiphonia, which have five or more 

pericentral cells per segment. 

Type. Neosiphonia flavimarina M.-S. Kim et I. K. Lee, 

1999:272.

There are six species of this section currently known in the 

northern Gulf of California. 

Neosiphonia cheloniae (Hollenberg et J. N. Norris) J. N. 

Norris, comb. nov.

FIGURE 127

Polysiphonia sphaerocarpa var. cheloniae Hollenberg et J. N. Norris, 

1977:16, figs. 4A–C, 6A; Norris, 1985d:213; González-González et al., 

1996:257. 

Algae up to 3.5 cm high; main branches up to 300 μm in 

diameter, uncorticated; polysiphonous segments of 4 pericentral cells, segments 1.0–2.5(–3.0) times as long as the diameter; 

branching subdichotomous; attached by a basal tuft of rhizoids, 

augmented by rhizoids from assurgent branches. Each rhizoid 

cut off as separate cell from the proximal end of its pericentral 

cell. Branches narrowed toward their base; developed from an 

entire trichoblast primordium at intervals of mostly 5–12 segments. Trichoblasts 1 per segment, up to 400 μm long, dichotomously divided 1–3 times, tapering to delicate apices.

Tetrasporangia unknown. Cystocarps globular, up to 370 

μm in diameter. Spermatangial stichidia cylindrical to fusiform, 

160–175 μm long by 40–48 μm in diameter, mostly without sterile apices at maturity; arising as a primary fork of a trichoblast. 

Habitat. On carapace of a living black sea turtle, 

Chelonia mydas agassizii (Bocourt, 1868; see Cliffton et al., 

1995; Parham and Zug, 1996), found overwintering subtidally 

on the bottom; surface to subtidal.

FIGURE 127. Neosiphonia cheloniae: A. Upper region with numerous trichoblasts at apices and spermatangial stichidia. B. Spermatangial 

stichidia arising as a primary fork of a fertile trichoblast (A, B, JN-4765.5, US Alg. Coll. microscope slide 5046). 
264 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Distribution. Gulf of California: Canal de Infiernillo, between coast of Sonora and east coast of Isla Tiburón 

(Islas de la Cintura).

Type Locality. Epizoic on a black sea turtle, Chelonia mydas agassizii; in Canal de Infiernillo, off the mainland 

coast of Sonora between Campo Ona and Campo Viboras, opposite the east coast of Isla Tiburón, Sonora, Gulf of California, 

Mexico.

Remarks. Neosiphonia cheloniae is thus far known 

only on the black sea turtles in the Gulf of California (Hollenberg and Norris, 1977), which are known to overwinter in this 

region (Felger et al., 1976). It is one of several epizoic algae 

known on sea turtles (Sentíes-G. et al., 1999; Báez et al., 2002), 

including Polysiphonia carettia Hollenberg (1971a), a species 

found on loggerhead sea turtles, Caretta caretta (Linnaeus), in 

the eastern Pacific, Atlantic, and Mediterranean Sea (Abbott and 

Hollenberg, 1976; Báez et al., 2001).

Neosiphonia eastwoodae (Setchell et N. L. Gardner) 

J. N. Norris, comb. nov.

FIGURE 128D

Polysiphonia eastwoodae Setchell et N. L. Gardner, 1930:161; Dawson, 

1954b:160; Kapraun et al., 1983:881, figs. 25–29; Stewart and Stewart, 1984:147; Young and Kapraun, 1985:107, figs. 11–16; R. AguilarRosas and Machado-Galindo, 1990:188; González-González et al., 

1996:323. 

Polysiphonia mollis sensu Dawson, 1957a:8; 1957c:22; 1959a:32; 

Dawson et al., 1960a:72, pl. 41: figs. 7, 8; Hollenberg, 1961:359, 

pl. 4: fig. 2; Dawson, 1961b:450; 1962b:216, fig. 127; 1966a:29; 

Chávez-Barrear, 1972b:269; Abbott and Hollenberg, 1976:688, 

fig. 636; Hollenberg and Norris, 1977:9, fig. 5b; Huerta-Múzquiz, 

1978:336; Stewart and Stewart, 1984:147; Huerta-Múzquiz and 

Mendoza-González, 1985:54; Mendoza-González and Mateo-Cid, 

1986:425; Ortega et al., 1987:75, pl. 10: fig. 43, pl. 11: figs. 44–46 

; Stewart, 1991:166; Mateo-Cid and Mendoza-González, 1992:22; 

Serviere-Zaragoza et al., 1993a:484; Mateo-Cid et al., 1993:49; 

Mendoza-González et al., 1994:109; Sentíes-G., 1995:42, figs. 13–

17; González-González et al., 1996:255; Silva et al., 1996b:233; 

Hoffman and Santelices, 1997:388, fig. 109:1–6; L. Aguilar-Rosas 

et al., 2000:132; Cruz-Ayala et al., 2001:191; CONANP, 2002:139; 

López et al., 2004:12; Dreckmann et al., 2006:155; Pérez-Estrada 

et al., 2012:191 [non Polysiphonia mollis J. D. Hooker et Harvey 

in Harvey, 1848a:43]. 

Polysiphonia senticulosa sensu Snyder in Collins et al., 1899: Fasciculus 8, 

No. 638 [type of Polysiphonia snyderae Kylin, 1941:35; non Polysiphonia senticulosa Harvey, 1862:160].

Polysiphonia snyderae Kylin, 1941:35, pl. 12: fig. 34 [type specimen]; Hollenberg, 1942a:784, fig. 9; Dawson, 1944a:330; 1951:56; 1954b:160; 

Stewart and Stewart, 1984:147; González-González et al., 1996:257. 

Polysiphonia tongatensis sensu Setchell and Gardner, 1930:160; Segi, 

1951:207 [in part; only Pacific Mexico material; non Polysiphonia 

tongatensis Harvey ex Kützing, 1864:14, which is now Neosiphonia 

tongatensis (Harvey ex Kützing) M.-S. Kim et I. K. Lee, 1999:280; =P. 

mollis var. tongatensis (Harvey ex Kützing) Hollenberg ex P. C. Silva, 

Meñez et Moe, 1987:70; =P. mollis var. tongatensis (Harvey ex Kützing) Hollenberg, 1968a:69, nom. illeg.].

Neosiphonia tongatensis sensu Pacheco-Ruíz et al., 2008:213 [non Neosiphonia tongatensis (Harvey ex Kützing) M.-S. Kim et I. K. Lee, 1999:280].

Algae erect, mostly 5–12 cm long; main branches repeatedly subdichotomously branched above, lower portions usually without branches; polysiphonous segments of 4 pericentral 

cells; uncorticated; dull reddish brown; arising above prostrate 

branches of limited extent or sometimes from a discoid base; 

attached by unicellular rhizoids frequently with digitate ends; 

rhizoids 1–2(–5) per segment cut off by a curving wall from 

the proximal ends of pericentral cells. Erect branches 300–400 

μm in diameter below, mostly 60–180 μm in diameter in upper 

parts; segments in main branches mostly 1–2 times as long as 

the diameter but sometimes considerably longer. Trichoblasts 1 

per segment in spiral sequence, with 1⁄4 divergence; deciduous, 

leaving persistent scar cells; branch replacing a trichoblast in 

the spiral sequence at irregular intervals; usually 6–10 segments 

apart.

Tetrasporangia 60–70 μm in diameter; in spiral series in the 

ultimate and subultimate branches. Cystocarps ovoid to nearly 

globular, 300–350 μm in diameter. Spermatangial stichidia constitute a primary branch of a trichoblast.

Habitat. Epiphytic on other algae or growing on 

rock, wood, or shells or epizoic on hydroids; intertidal.

Distribution. Gulf of California: El Tornillal to 

Bahía de San Lucas; Mazátlan; Sinaloa to Nayarit. Eastern Pacific: Alaska to northern Baja California; Santa Catalina Island 

(California Channel Islands); Rocas Alijos; Guerrero; Chiapas.

Type Locality. On rocks; South Anchorage, Isla 

Guadalupe (off Baja California), Pacific Mexico.

Remarks. The new combination N. eastwoodae 

is proposed on the basis of characteristics that are in general 

agreement with Neosiphonia—rhizoids that are cut off from the 

pericentral cells, numerous trichoblasts and scar cells in spiral sequence, tetrasporangia arranged in spiral series, and spermatangia developed on primary branch of trichoblast. 

Hollenberg (1961, 1968a) observed that the branches of N. 

eastwoodae replaced the trichoblasts in development, thus differing from P. mollis where the branches developed in the axils 

of trichoblasts (see also Womersley, 1979; Young and Kapraun, 

1985, as P. eastwoodae). M.-S. Kim and Lee (1999, as P. eastwoodae) considered the Pacific Mexico N. eastwoodae to be a 

synonym of the South Pacific N. tongatensis (Harvey ex Kützing) 

M.-S. Kim et I. K. Lee (1999; basionym: P. tongatensis Harvey ex 

Kützing, 1864). However, primarily on the basis of the disjunct 

distribution of the two, they are retained as separate species 

herein, with Neosiphonia eastwoodae being a cold temperate 

to subtropical species and N. tongatensis being a tropical species. Records of Pacific Mexico material referred to “P. mollis” 

should be reexamined. The relationship of the Gulf of California 

N. eastwoodae to the Pacific Mexico N. eastwoodae (type locality Isla Guadalupe, Baja California), California type locality P. 

snyderae, and the tropical western Pacific N. tongatensis (type 
NUMBER 96 • 265

locality: Tonga) should be further compared and tested using 

molecular analyses. 

Neosiphonia flaccidissima (Hollenberg) M.-S. Kim et I. K. Lee

FIGURE 129

Polysiphonia flaccidissima Hollenberg, 1942b:783, figs. 8, 19; Hollenberg, 

1961:351, pl. 2: fig. 2; Dawson, 1961b:449; 1962b:217, fig. 128; Dawson et al., 1964:88, pl. 78: fig. b; Hollenberg, 1968a:63, figs. 2A, 11; 

Huerta-Múzquiz and Tirado-Lizárraga, 1970:129; Huerta-Múzquiz 

and Garza-Barrientos, 1975:9; Abbott and Hollenberg, 1976:688, 

fig. 634; Hollenberg and Norris, 1977:4, fig. 2e; Kapraun and Norris, 1982:231, fig. 110a–d; Schnetter and Bula-Meyer, 1982:172, pl. 

32: figs. E–H; Young and Kapraun, 1985:108, figs. 17–22; Stewart 

and Stewart, 1984:146; Stewart, 1991:164; Ramírez and Santelices, 

1991:376; Mateo-Cid and Mendoza-González, 1992:22; ServiereZaragoza et al., 1993a:484; Mateo-Cid et al., 1993:49; Mateo-Cid 

and Mendoza-González, 1994b:42; Sentíes-G., 1995:42, figs. 8–12; 

González-González et al., 1996:324; Mendoza-González and MateoCid, 1996b:69, pl. 13: figs. 49–55; M.-S. Kim and Lee, 1996:143, fig. 5; 

Abbott, 1999:414, fig. 121A–D; Masuda et al., 2000:575, figs. 24–31; 

Fernández-García et al., 2011:63. 

Neosiphonia flaccidissima (Hollenberg) M.-S. Kim et I. K. Lee, 1999:279. 

FIGURE 128. Species of Neosiphonia. A. Neosiphonia concinna: Apical portion of a branch (after Hollenberg, 1944: fig 10, as Polysiphonia 

concinna). B. Neosiphonia confusa: Apical portion of a branch showing trichoblasts, scar cells, and a branch arising exogenously in connection 

with a trichoblast (after Hollenberg, 1961: pl. 1: fig. 5, as Polysiphonia confusa). C. Neosiphonia johnstonii var. johnstonii: Apical portion of an 

axis showing trichoblasts and incurved tips (after Hollenberg and Norris, 1977: fig. 2B, as Polysiphonia johnstonii). D. Neosiphonia eastwoodae: Branch tip (after Hollenberg and Norris, 1977: fig. 5B, as “Polysiphonia mollis”). E, F. Neosiphonia masonii: Terminal portion of axes, 

tetrasporangia in spiral series (after Hollenberg, 1961: pl. 6: figs. 2, 3, as Polysiphonia masonii). 
266 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Polysiphonia sertularioides sensu L. Aguilar-Rosas et al., 2000:1341; 

L. Aguilar-Rosas et al., 2002:235; Serviere-Zaragoza et al., 2007:11; 

Bernecker, 2009:CD-Rom p. 67; [non Polysiphonia sertularioides (Grateloup) J. Agardh, 1863:969; basionym: Ceramium sertularioides Grateloup, 1806:[1], fig. IV].

Algae 10–25 mm high, erect, axes and branches uncorticated, with thin hyaline walls; polysiphonous segments of 4 

pericentral cells; branching to many orders, arising from creeping basal branches attached by numerous unicellular rhizoids, 

each cut off as separate cell from the proximal end of pericentral 

cells. Main erect axes (50–)70–80 μm in diameter, with segments 

mostly (50–)70–160 μm long (1–2 times as long as the diameter). 

Branches gradually narrowed at both ends (base and apex); at 

first usually curving toward the parent branch; up to 2.5 mm 

long, 35–55 μm in diameter, segments mostly 35–100 μm long; 

branches arising exogenously at base of trichoblasts from common primordium, mostly at irregular intervals of 5–6 (rarely 12) 

segments. Trichoblasts mostly with a single dichotomy or occasionally simple, arising 1 per segment with 1⁄4 divergence in spiral sequence; trichoblasts tapering to slender apices; deciduous, 

leaving persistent scar cells.

Tetrasporangia 50–70 μm in diameter; in spiral series, somewhat distending the segments in smaller branches. Cystocarps 

globular. Spermatangial stichidia originating as a primary branch 

of a trichoblast with apices of 1–2 sterile cells.

Habitat. On rocks or occasionally epiphytic; intertidal to shallow subtidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara); Bahía San Carlos (north of Guaymas) to 

Canal de San Lorenzo (off southern end of Isla Espíritu Santo); 

Nayarit to Jalisco. Eastern Pacific: Santa Catalina Island (California Channel Islands); southern California to Todos Santos, 

Baja California Sur; Isla Guadalupe; Isla Socorro (Islas Revillagigedo); Colima to Chiapas; El Salvador; Costa Rica; Panama; 

Colombia; Peru. Central Pacific: Hawaiian Islands.

Type Locality. On a coralline alga; rocky point, 

Laguna Beach, Orange County, California, USA.

Remarks. Womersley (1979:478, with a taxonomic 

query), although noting “no apparent differences,” tentatively 

suggested the southern California P. flaccidissima may be a synonym of P. sertularioides (Grateloup) J. Agardh (1863; basionym: type locality: Cette, Golfe du Lion, France). Subsequently, 

Silva et al. (1996a) considered the two conspecific. However, 

others have observed differences between the two (e.g., Young 

and Kapraun, 1985; M.-S. Kim and Lee, 1996, 1999; Masuda 

et al., 2000; Dreckmann et al., 2006). To test the taxonomic 

FIGURE 129. Neosiphonia flaccidissima: A. Branch tip with abundant trichoblasts (JN-4266, US Alg. Coll. microscope slide 5029). B. Lateral 

branch and trichoblast arising from same primordium (arrowhead), scar cell (arrow). C. Apical region showing lateral branch and trichoblast 

from same primordium (arrow), trichoblasts one per segment, spirally arranged (B, C, JN-4270, US Alg. Coll. microscope slide 5031).
NUMBER 96 • 267

status of the Gulf specimens referred to Neosiphonia flaccidissima, molecular analyses and morphological comparisons of 

newly collected Gulf specimens with the type locality specimens 

of southern California P. flaccidissima and the French Mediterranean P. sertularioides need to be performed. 

Neosiphonia masonii (Setchell et N. L. Gardner) J. N. Norris, 

comb. nov.

FIGURE 128E,F 

Polysiphonia masonii Setchell et N. L. Gardner, 1930:160; Hollenberg, 

1942b:783; Dawson, 1954d:160; 1961b:450; Hollenberg, 1961:358, 

pl. 6: figs. 2, 3; Hollenberg and Norris, 1977:8, fig. 2d; Stewart and 

Stewart, 1984:147; Sánchez-Rodríguez et al., 1989:45; GonzálezGonzález et al., 1996:255. 

Algae 2–3 cm high, flaccid; uncorticated, of polysiphonous 

segments of 4 pericentral cells; segments mostly as long as wide 

(diameter); main axis 350–400 μm in diameter in lower portions, branched repeatedly and regularly dichotomously above; 

attached by bundle of short unicellular rhizoids, with digitate 

ends, issued from the lower segments of the erect primary axis. 

Branches arising from an entire trichoblast primordium; more or 

less of same size as main axis at the point of insertion. Trichoblasts 1 per segment in spiral sequence with 1⁄4 divergence; up to 

480 μm long, dichotomously branched 2–3 times; tapering to 

very slender apices; deciduous, leaving persistent scar cells. 

Tetrasporangia 85–95 μm in diameter; in spiral series in the 

ultimate branches, barely distending the segments. Cystocarps 

subspherical, 300–325 μm diameter, nearly sessile on branches. 

Spermatangial stichidia broadly fusiform; arising from a primary 

branch of a trichoblast.

Habitat. Epiphyte on sea grass and probably on marine algae; intertidal.

Distribution. Gulf of California: Puerto Peñasco. 

Eastern Pacific: Isla Guadalupe; Bahía Magdalena, Baja California Sur. 

Type Locality. Epiphytic on Zostera; Isla Guadalupe, off Baja California, Pacific Mexico.

Remarks. Apparently rare, Neosiphonia masonii is 

known only from Puerto Peñasco in the upper Gulf of California 

and in Pacific Mexico from Isla Guadalupe and Bahía Magdalena.

Neosiphonia savatieri (Hariot) M.-S. Kim et I. K. Lee

FIGURE 130

Polysiphonia savatieri Hariot, 1891:226; Segi, 1951:202, figs. 10, 11, pl. 

3: fig. 8; Dawson, 1954d:160; Hollenberg, 1961:363, pl. 7: fig. 4; 

Dawson, 1961b:450; Hollenberg, 1968a:77, figs. 37, 38; Abbott and 

FIGURE 130. Neosiphonia savatieri: A. Upper portion of thallus with tetrasporangia arranged in spiral series, distending segments a little; apices 

with abundant trichoblasts that are soon deciduous (JN-4195, US Alg. Coll. microscope slide 5027). B. Maturing cystocarp and scar cell left 

behind by deciduous trichoblast (JN-4266, US Alg. Coll. microscope slide 5030).
268 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Hollenberg, 1976:692, fig. 639; Hollenberg and Norris, 1977:12, fig. 

8a; Young and Kapraun, 1985:112, figs. 29–34; Stewart and Stewart, 

1984:147; Santelices and Abbott, 1987:9; Stewart, 1991:167; Ramírez 

and Santelices, 1991:378; González-González et al., 1996:256; Yoshida, 1998:1070; Abbott, 1999:424, fig. 125B.

Neosiphonia savatieri (Hariot) M.-S. Kim et I. K. Lee, 1999:279; Masuda 

et al., 2001:474, figs. 24–31; Lobban and Tsuda, 2003:78; M.-S. Kim, 

2005:164, figs.1–4[lectotype: Polysiphonia savatieri Hariot], figs. 5–20; 

Y.-P. Lee, 2008:315, figs. A–F.

Polysiphonia japonica var. savatieri (Hariot) H. S.Yoon, 1986:34, figs. 20, 

21, pl. 9E–J [non Polysiphonia japonica Harvey, 1857:331; see M.-S. 

Kim, 2005:172].

Polysiphonia minutissima Hollenberg, 1942b:781, fig. 21; GonzálezGonzález et al., 1996:255.

Algae dull reddish brown, erect, 3–10 mm high; polysiphonous segments of 4 pericentral cells, uncorticated; main axes indistinct, to 150 μm diameter, branching dichotomously to several 

orders; axes arising from a basal attachment tuft (or cushion) of 

rhizoids that usually penetrates the host tissue. Basal rhizoids up 

to 1 mm long, cut off by a curving wall from the proximal end 

of the pericentral cells. Branches exogenous (not associated with 

trichoblasts in origin), at variable intervals. Trichoblasts relatively short, 1 per segment in spiral sequence, with 1⁄4 divergence; 

deciduous, leaving persistent scar cells. 

Tetrasporangia up to 80 μm in diameter; in spiral series, 

somewhat distending the segments, in upper portions of axes. 

Cystocarps slightly urceolate or mostly globular, 225–290 μm in 

diameter. Spermatangial stichidia about 135 μm long and 40 μm 

in diameter, without a sterile apex; forming 1 primary branch of 

a trichoblast. 

Habitat. Epiphytic on various algae, including Codium, Dictyota, Sargassum, Gracilaria, Gelidium, and Sarcodiotheca, or growing on rocks or in tide pools; mid intertidal to 

shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de Las Ánimas; Guaymas. Eastern Pacific: central California to northern Baja California; Santa Catalina Island (California Channel Islands); Isla Guadalupe (off Baja California); 

Chile. Western Pacific: Japan; Korea.

Type Locality. Epiphytic on larger algae; Yokosuka, on Tokyo Bay, Kanagawa Prefecture, Honshū, Japan.

Remarks. The taxonomic interpretation of Polysiphonia savatieri has been somewhat unclear, and the species 

concept may involve more than one species. Yoon (1986, as 

P. japonica var. savatieri) reduced P. savatieri to varietal status 

of the Japanese P. japonica. Later, Abbott (1999, as P. savatieri) 

retained the Hawaiian material as a species but noted that it may 

not be the same as the Japanese and Korean species. M.-S. Kim 

and Lee (1999) considered that the western Pacific P. savatieri

belonged to the genus Neosiphonia, and M.-S. Kim (2005, as 

N. savatieri), studying the types, concluded that P. savatieri was 

a species distinct from P. japonica.

Earlier, Hollenberg (1968b) noted that Hawaiian and other 

tropical specimens of P. savatieri may be variants of P. sphaerocarpa Børgesen (1918; now Neosiphonia sphaerocarpa (Børgesen) M.-S. Kim et I. K. Lee, 1999) but separated the two on the 

tendency of P. savatieri to be erect from a basal tuft of rhizoids 

versus P. sphaerocarpa, which is decumbent and has rhizoids distributed along its prostrate segments (characters also emphasized 

by M.-S. Kim, 2005).

For now, on the basis of characters observed in Gulf of California N. savatieri, they are retained in Neosiphonia. Culture, 

genetic, and comparative reproductive developmental studies are 

needed to test the status of the Gulf N. savatieri and its relationship to the type of N. savatieri (Japan) as well as other geographically widespread specimens referred to “P. savatieri” to see if the 

complex involves more than one taxa.

Neosiphonia simplex (Hollenberg) Y.-P. Lee

FIGURE 131C,D

Polysiphonia simplex Hollenberg, 1942b:782, fig. 18; Dawson, 1944a:331; 

1951:53; 1954b:160; Hollenberg, 1961:364, pl. 5: fig. 1; Dawson, 

1961b:450; 1966a:29; Abbott and Hollenberg, 1976:694, fig. 641; 

Huerta-Múzquiz and Garza-Barrientos, 1975:9, 12 ; Hollenberg and 

Norris, 1977:14, fig. 9; Young and Kapraun, 1985:113, figs. 41–44; 

Huerta-Múzquiz and Mendoza-González, 1985:54; Sánchez-Rodríguez 

et al., 1989:46; Mateo-Cid and Mendoza-González, 1992:23; 

Mendoza-González and Mateo-Cid, 1992:21; Serviere-Zaragoza et 

al., 1993a:484; Mateo-Cid et al., 1993:49; Mateo-Cid and MendozaGonzález, 1994b:42; Mendoza-González et al., 1994:109; Sentíes-G., 

1995:47: figs. 25–29; González-González et al., 1996:256; RiosmenaRodríguez et al., 1998:26; Abbott, 1999:426, fig. 126D; Mateo-Cid et 

al., 2000:67; L. Aguilar-Rosas et al., 2000:132; CONANP, 2002:139; 

Pacheco-Ruíz and Zertuche-González, 2002:469; López et al., 2004:12; 

Mateo-Cid et al., 2006:57, 62; Dreckmann et al., 2006:155; ServiereZaragoza et al., 2007:11; Pacheco-Ruíz et al., 2008:213; Bernecker, 

2009:CD-Rom p. 68; Fernández-García et al., 2011:63; Pérez-Estrada 

et al., 2012:191. 

Neosiphonia simplex (Hollenberg) Y.-P. Lee, 2008:316, figs. A–F.

Algae composed of polysiphonous filaments of 4 pericentral 

cells per segment; often spreading, forming mats; medium to dark 

brownish red (drying nearly black). Erect branches 1–3(–7) cm 

FIGURE 131. (Opposite) Species of Neosiphonia. A, B. Neosiphonia confusa: A. Apical portion of thallus showing trichoblasts and some of 

its 8 pericentral cells per segment (JN-5577, US Alg. Coll. microscope slide 5052). B. Cystocarps (JN-3835, US Alg. Coll. microscope slide 

5000). C, D. Neosiphonia simplex: C. Upper portion of thallus showing delicate trichoblasts (JN-5098b, US Alg. Coll. microscope slide 4996).

D. Upper portion of a thallus with young cystocarps (JN-5038, US Alg. Coll. microscope slide 4994). 
NUMBER 96 • 269
270 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

high and 160–250 μm in diameter near the base; developed in 

an exogenous assurgent manner; main axes usually distinct (but 

not prominent), sparingly branched, arising from creeping basal 

branches of short segments, 250–360 μm in diameter; attached 

by numerous unicellular rhizoids cut off as a separate cell from 

the proximal end of a pericentral cell, often digitate at their end. 

Branches exogenous, radially directed, of several orders. Trichoblasts up to 730 μm long, with 1 or 2 dichotomies; 1 per segment 

in spiral sequence with 1⁄4 divergence; delicate, deciduous, leaving persistent scar cells; branches replacing trichoblasts in the 

spiral (arising from an entire trichoblast primordium).

Tetrasporangia mostly about 70 μm in diameter; in spiral 

series within the ultimate branches, more or less distending the 

segments. Cystocarps ovoid to globular, 300–350 μm in diameter. Spermatangial stichidia, elongate, 100–170 μm long, 35–40 

μm in diameter, apex without sterile cells; comprising 1 primary 

branch fork of a trichoblast. 

Habitat. Solitary or mixed with other turf algae, 

sometimes forming spreading mats; usually on rocks and tidal 

platforms and in tide pools or occasionally epiphytic on other 

algae, such as Gastroclonium or Amphiroa; mid intertidal to 

shallow subtidal, down to 8 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena; Mazatlán; Sinaloa to Nayarit. Eastern Pacific: Santa Catalina Island (California Channel Islands); southern California to Todos Santos, Baja California Sur; Isla Socorro 

and Isla San Benedicto (Islas Revillagigedo); Colima; Guerrero 

to Chiapas; Costa Rica. Central Pacific: French Frigate Shoals, 

Northwestern Hawaiian Islands. Western Pacific: Korea.

Type Locality. On intertidal rocks; Laguna Beach, 

Orange County, southern California, USA.

Remarks. McIvor et al. (2001) found that “Neosiphonia simplex,” as identified from San Diego, California 

(e.g., Stewart, 1991, as Polysiphonia simplex), was actually an 

introduced species, Neosiphonia harveyi (J. W. Bailey) M.-S. 

Kim, H.-G. Choi, Guiry et G. W. Saunders (in Choi et al, 2001a; 

basionym: Polysiphonia harveyi J. W. Bailey, 1848) from the 

Western Atlantic. More recently, N. harveryi was discovered in 

Humbolt Bay, northern California (Hughey et al., 2009; Miller 

at al., 2011). To determine whether one or both of these species 

occur southward, specimens identified as “N. simplex” in Pacific 

Mexico and in the Gulf of California should be reexamined and 

molecularly compared with type locality specimens of N. simplex and N. harveryi (lectotype locality: Connecticut, northwest 

Atlantic; Maggs and Hommersand, 1993). 

Neosiphonia sect. Multisiphonia

J. N. Norris, sect. nov.

Latin Diagnosis. Algae huius sectionis cellulis 

pericentralibus quinque vel plus per segmentum; differt N. sect. 

Neosiphonia cellulis pericentralibus quaterni per segmentum.

Members of Neosiphonia sect. Multisiphonia are characterized by having five or more pericentral cells per polysiphonous 

segment, thus differing from members of N. sect. Neosiphonia, 

which has species with 4 pericentral cells per segment grouped 

around each axial filament cell. 

Type. Neosiphonia johnstonii (Setchell et N. L. Gardner) J. N. Norris, herein (basionym: Polysiphonia johnstonii 

Setchell et N. L. Gardner, 1924:767). 

There are five species of this taxonomic section currently 

known in the northern Gulf of California.

Neosiphonia concinna (Hollenberg) J. N. Norris, comb. nov.

FIGURE 128A

Polysiphonia concinna Hollenberg, 1944:474, fig. 10; Dawson, 1951:53, 56; 

1954d:159; 1959a:32; González-González et al., 1996:253. 

Polysiphonia johnstonii var. concinna (Hollenberg) Hollenberg, 1961:358, 

pl. 3: fig. 4; Dawson, 1961b:450; Abbott and Hollenberg, 1976:699, 

fig. 650; Hollenberg and Norris, 1977:7, figs. 2a, 4d; Stewart and Stewart, 1984:147; Huerta-Múzquiz and Mendoza-González, 1985:54; 

Mendoza-González and Mateo-Cid, 1985:32; Sánchez-Rodríguez et 

al., 1989:45; Stewart, 1991:165; González-González et al., 1996:254; 

L. Aguilar-Rosas et al., 2000:132; Pacheco-Ruíz and ZertucheGonzález, 2002:469; Hernández-Herrera et al., 2005:148; CastañedaFernández de Lara et al., 2010:200.

Algae up to 2(–4) cm tall; branching axes, uncorticated, of 

polysiphonous segments of 5 pericentral cells; segments short 

(usually about half as long as wide), 300–400 μm in diameter, 

about 150–200 μm tall; attached by basal tuft of unicellular rhizoids. Trichoblasts short and simple (unbranched) or lacking; 

scar cells regular, 1 per segment in spiral arrangement.

Tetrasporangia 1 per segment; spirally arranged in ultimate 

branchlets. Cystocarps observed in northern Gulf specimens: 

immature about 65–120 μm in diameter, mature to 360 μm in 

diameter. Spermatangia arising as a primary branch of a trichoblast in Gulf material. 

Habitat. Epiphytic on various algae, including Codium, Padina, and Tacanoosca; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía Agua Verde; Isla Venado, off Mazatlán, Sinaloa to 

Jalisco. Eastern Pacific: Santa Catalina Island (California Channel Islands), southern California to Bahía Magdalena, Baja California Sur; Isla Guadalupe.

Type Locality. Epiphytic on other algae; near 

Scripps Institution of Oceanography (University of California, San 

Diego), La Jolla, San Diego County, southern California, USA. 

Remarks. Neosiphonia concinna has spirally arranged tetrasporangia, a character of Neosiphonia. Although 

similar to N. johnstonii, N. concinna differs in being smaller and 

in having five very short pericentral cells per segment. Further 

vegetative and reproductive comparisons, along with genetic 

testing, with type locality materials are needed to clarify the taxonomic status of this species.

A Bahía de Los Angeles specimen (Islas de Los Gemelos, 

JN-3011; US Alg. Coll. microscope slide 5009), tentatively referred to “P. johnstonii var. concinna” by Hollenberg and Norris (1977:7), was unusal in that its branches arise in pairs, one 
NUMBER 96 • 271

segment apart—a feature not observed in other northern Gulf N. 

concinna. Also there were several immature cystocarps, possibly 

in arrested development (Hollenberg and Norris, 1977: fig. 4D). 

Further collections are needed to elucidate its identity.

Neosiphonia confusa (Hollenberg) J. N. Norris, comb. nov.

FIGURES 128B, 131A,B

Polysiphonia confusa Hollenberg, 1961:350, pl. 1: fig. 5; Dawson, 

1961b:449; Dawson et al., 1964:87, pl. 33: fig. d; Abbott and Hollenberg, 1976:696, fig. 643; Hollenberg and Norris, 1977:2, fig. 1; Dreckmann et al., 1990:32; Sentíes-G. et al., 1990:95, pl. 1: figs. 1–4; Stewart, 

1991:164; Ramírez and Santelices, 1991:375; Stout and Dreckmann, 

1993:16; Sentíes-G., 1995:40, figs. 1–7; González-González et al., 

1996:253; López et al., 2004:12; Hernández-Herrera et al., 2005:148; 

R. Aguilar-Rosas et al., 2006b:1, figs.1–7; Castañeda-Fernández de 

Lara et al., 2010:200.

Polysiphonia inconspicua Hollenberg, 1944:479, nom. illeg.; GonzálezGonzález et al., 1996:254 [non Polysiphonia inconspicua Reinsch, 

1888:146].

Algae erect, branched axes, 0.8–1.5(–3.0) cm high, and 

prostrate, basal branches composed of polysiphonous segments 

of 8–10 pericentral cells; uncorticated; arising from prostrate 

branches 100–175 μm in diameter, of segments about as long 

as the diameter or somewhat longer; attached by numerous 

unicellular rhizoids, 1 to several per segment; rhizoids cut off 

from the proximal ends of the pericentral cells, frequently ending with digitate disc. Erect branches 60–150 μm in diameter, 

of segments 1.0–2.5 times as long; lateral branches arising exogenously in connection with trichoblasts at irregular intervals. 

Trichoblasts up to 1 mm long, with 1–2 dichotomies; 1 per segment in spiral sequence with 1⁄4 divergence; deciduous, leaving 

persistent scar cells.

Tetrasporangia, 60–80 μm in diameter; in spiral series in 

slightly swollen segments of ultimate and subultimate branches. 

Cystocarps globular, up to 225 μm in diameter. Spermatangial 

thalli unknown in northern Gulf.

Habitat. Epizoic on sand dollars, epiphytic on Codium, and growing near surface on a floating buoy and probably 

on other hard substrata as well; mid to low intertidal. 

Distribution. Gulf of California: Puerto Peñasco 

to El Desemboque de San Ignacio; Jalisco. Eastern Pacific: Corona del Mar, southern California, to Bahía Tortugas (inside 

southeast Bahía San Bartolomé), Baja California Sur; Michoacán 

to Oaxaca; Peru.

Type Locality. Mid intertidal rocks; Corona del 

Mar, Orange County, southern California, USA. 

Remarks. Characters of northern Gulf specimens 

referred to Neosiphonia confusa are in general agreement with 

the genus Neosiphonia. However, spermatangial thalli are not 

yet known in the northern Gulf. Pacific Mexico specimens from 

northern Baja California had both tetraspores and cystocarps 

on the same individual (R. Aguilar-Rosas et al., 2006b:2, fig. 

6, as Polysiphonia confusa). Finding northern Gulf spermatangial specimens is needed to confirm its identification and for 

molecular comparisons with type locality specimens to elucidate 

their phylogenetic relationship.

Neosiphonia johnstonii (Setchell et N. L. Gardner) J. N. Norris, 

comb. nov.

FIGURE 128C

Polysiphonia johnstonii Setchell et N. L. Gardner, 1924:767; Hollenberg, 

1944:475, figs. 4, 5; Dawson, 1944a:329; 1949c:237; 1951:53, 57; 

1954d:160; 1959b:32; 1960a:72, pl. 41: figs. 5, 6; Dawson et al., 

1960b:26; Hollenberg, 1961:357, pl. 2: figs. 4, 5; Dawson, 1966a:29; 

Norris, 1973:16; Abbott and Hollenberg, 1976:699, fig. 649; Hollenberg and Norris, 1977:4, figs. 2b, 3; Huerta-Múzquiz, 1978:338; 

Huerta-Múzquiz and Mendoza-González, 1985:52; Sánchez-Rodríguez 

et al., 1989:45; Stewart, 1991:165; González-González et al., 1996:254; 

Anaya-Reyna and Riosmena-Rodríguez, 1996:864, tbl. 1; RiosmenaRodríguez et al., 1998:26;; León-Tejera and González-González, 

2000:328; Cruz-Ayala et al., 2001:191; CONANP, 2002:139; PachecoRuíz and Zertuche-González, 2002:469; Pacheco-Ruíz et al., 2008:213; 

Pérez-Estrada et al., 2012:191. 

Polysiphonia marchantae Setchell et N. L. Gardner, 1924:768, pl. 49a. 

Polysiphonia sinicola Setchell et N. L. Gardner, 1924:769. 

Polysiphonia acuminata sensu Dawson, 1950a:68; 1954d:159 [non Polysiphonia acuminata N. L. Gardner, 1927f:100]. 

Polysiphonia richardsoni sensu Segi, 1951:253; Dawson, 1954b:160 [in part; 

with reference only to Gulf of California specimens cited by Setchell and 

Gardner, 1924:768, as “P. marchantae”; non Polysiphonia richardsoni

W. J. Hooker ex Harvey in W. J. Hooker, 1833:333, which is now Polysiphonia fibrillosa (Dillwyn) Sprengel, 1827:349]. 

Algae of several erect, repeatedly branched primary axes, 

5–8(–12) cm high and up to 1.0 mm in diameter (near base); 

uncorticated; polysiphonous segments of (5–)6 pericentral cells, 

1.5 times or more longer than diameter (up to 1 mm in length 

near base); attached by numerous unicellular rhizoids, each cut 

off as separate cells from pericentral cells of the prostrate basal 

axes. Branches replacing trichoblasts in origin at irregular intervals, spirally arranged, initially at narrow angle, angle becoming wider with growth; ultimate branches usually relatively close 

and dense. Trichoblasts unbranched, or 1–2 times forked; 1 per 

segment in spiral sequence, with 1⁄5 or 1⁄6 divergence; deciduous, 

leaving persistent scar cells. 

Tetrasporangia 70–90 μm in diameter; 1(–2) per segment 

in spiral series in branchlets. Cystocarps globular, 450–500 μm 

in diameter, nearly sessile on branches. Spermatangial stichidia 100–140 long, 30–40 μm in diameter; arising as a primary 

branch of a trichoblast.

Habitat. Usually epiphytic on other algae such as 

Sargassum, Gracilaria, and Osmundea sinicola or sometimes on 

rocks; intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Punta Los Frailes; Sinaloa. Eastern Pacific: Santa Catalina 

Island (California Channel Islands) to Bahía Magdalena, Baja 

California Sur.

Type Locality. On Gracilaria sp.; Isla San Esteban, 

Islas de la Cintura, Gulf of California, Mexico.
272 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Neosiphonia mexicana (E. Y. Dawson) J. N. Norris, comb. nov.

FIGURE 132A–D

Lophosiphonia mexicana E. Y. Dawson, 1944a:333, pl. 48: figs. 7–10; 

1954b:347; 1954d:161; 1961b:451; Dawson and Hollenberg, 

1963:420, pl. 169: figs. 4–7; González-González et al., 1996:242; 

Serviere-Zaragoza et al., 2007:11; Pacheco-Ruíz et al., 2008:213. 

Algae small tufts, 1–2 mm tall; of polysiphonous erect and 

prostrate portions. Erect branches 1–2 mm long; lower portions 

of 6 pericentral cells, 50–60 μm in diameter; branches becoming 

wider in middle to upper portions, 70–80 μm in diameter, after 

6 pericentral cell segments divided to 12 pericentral cells; branch 

apices with only a few unbranched trichoblasts. Prostrate axes 

about 55 μm in diameter, attached by rhizoids in series, each rhizoid cut off from the middle of a pericentral cell (Figure 132D).

Tetrasporangia about 30–35 μm in diameter; in slightly irregular rows of 5–10 (tending toward spiral arrangement; cf. 

Figure 132A) in the upper segments of erect branches. Cystocarpic and spermatangial thalli not known.

Habitat. On rocks; low intertidal.

Distribution. Gulf of California: Isla Estanque, 

off Isla Ángel de la Guarda. Eastern Pacific: Isla Cedros (off Baja 

California); Bahía Sulphur, Isla Clarión (Islas Revillagigedo).

FIGURE 132. Species of Neosiphonia and Polysiphonia. A–D. Neosiphonia mexicana: A. Tetrasporangia in a series near 

apex. B. Apical region. C. Surface view of polysiphonous segments. D. Prostrate axis issuing erect axes and rhizoids (after 

Dawson, 1944a: pl. 48: figs. 7–10, as “Lophosiphonia mexicana”). E. Neosiphonia paniculata: Apical region with trichoblasts (after Hollenberg, 1944: fig. 7, as “Polysiphonia paniculata”). F. Polysiphonia sonorensis: Apical region (after Hollenberg and Norris, 1977: fig. 2C).
NUMBER 96 • 273

Type Locality. Isla Estanque (Pond Island), off 

southeast end of Isla Ángel de la Guarda (Islas de la Cintura), 

Gulf of California, Mexico.

Remarks. Problems concerning the taxonomic status of the genus Lophosiphonia Falkenberg (in Schmitz and 

Falkenberg, 1897; Falkenberg, 1901) have long been noted (e.g., 

Hollenberg, 1942b; Dawson, 1963a), although many recognize 

the genus (e.g., Norris, 1992a; Silva et al., 1996a; Abbott, 1999). 

Following the taxonomic criteria of Hollenberg (1968a:56), the 

Gulf of California L. mexicana E. Y. Dawson would not be a 

member of Lophosiphonia sensu stricto. Reexamination of isotype specimens of Lophosiphonia mexicana (E. Y. Dawson-430, 

US Alg. Coll.-6678, microscope slides 2836–2839) showed the 

attachment rhizoids are cut off from the basal pericentral cells 

of the segment, and the tetrasporangia illustrated by Dawson 

(1944a: pl. 48: fig. 10, a paratype from Isla Clarión) show a tendency toward spiraling in their arrangement. These characters 

suggest the taxon may be a Neosiphonia, and the combination

Neosiphonia mexicana is tentatively proposed.

Described from the northern Gulf, Neosiphonia mexicana

is known only from a few specimens. The longitudinal division of 6 pericentral cells in lower portions of erect branches 

to 12 pericentral cells in the mid to upper portions is unique 

among the Gulf species. Dawson (1944) observed the broad mid 

to upper portions of the branches tended towards being complanate and the 12 cells in the segments appeared to be paired 

(Figure 132C). More collections from the Gulf, particularly reproductive spermatangial and cystocarpic specimens, are needed 

to clarify and molecularly test its generic placement (Hollenberg 

and Norris, 1977). 

Neosiphonia paniculata (Montagne) J. N. Norris, comb. nov.

FIGURES 132E, 133

Polysiphonia paniculata Montagne, 1842a:254; Kützing, 1863:15, pl. 45c–e; 

Howe, 1914:142; Hollenberg, 1944:480, fig. 7; Taylor, 1947:86, pl. 

2: fig. 2; Dawson, 1954d:160; Dawson et al., 1960b:26; Dawson, 

1961b:450; Hollenberg, 1961:362, pl. 7: fig. 1; Dawson et al., 1964:89, 

pl. 78: fig. a, pl. 79; Dawson, 1966a:29; Smith, 1969:725; Abbott and 

Hollenberg, 1976:701, fig. 652; Hollenberg and Norris, 1977:11, figs. 

5a, 7; Silva, 1979:331; R. Aguilar-Rosas and Aguilar-Rosas, 1984:185, 

figs. 1–5; Scagel et al., 1989:234; Santelices, 1989:368, pl. ÑÑ: figs. 

17, 18; Stewart, 1991:166; Ramirez and Santelices, 1991:377; R. 

Aguilar-Rosas and Aguilar-Rosas, 1994:524; González-González et al., 

1996:256; Hoffman and Santelices, 1997:394, figs. 111.1–111.5; L. 

Aguilar-Rosas et al., 2000:132; 2002:235; Mateo-Cid et al., 2006:57. 

Polysiphonia californica Harvey, 1853:48; Setchell and Gardner, 1903:327; 

Howe, 1911:508; Kylin, 1941:36, fig. 7A–F; Dawson, 1944a:332; 

Smith, 1944:362, pl. 93: fig. 1. 

Algae densely tufted, soft, dark brownish red, 10–25 cm 

high (adhering to paper when dried); uncorticated; polysiphonous segments of (8–)10–12(–14) pericentral cells. Erect axes 

300–430 μm in diameter, segments 2.0–2.5(–4.0) times longer 

than diameter; unbranched to loosely branched in lower portions, 

becoming densely branched above; ultimate branches mostly 

densely plumose, narrowed at the base; arising endogenously at 

close intervals from lower, densely matted, prostrate branches; 

attached by numerous unicellular rhizoids, usually with digitate 

ends. Rhizoids usually 2 or 3 per segment, cut off as separate 

cells from the proximal end of pericentral cells. Trichoblasts up 

to 800 μm long, sometimes unbranched or mostly with 1 or 2 

dichotomies; 1 per segment in spiral sequence with 1⁄4 divergence; 

later deciduous, leaving relatively large scar cells; branches of all 

orders exogenous (arising in association with trichoblasts).

Tetrasporangia 80–100 μm in diameter, more or less spiraling in the ultimate and subultimate branches. Cystocarps 

globular to ovoid, somewhat truncate, 350–400 μm in diameter. 

Spermatangial stichidia 130–250 μm long, 50–70 μm in diameter; apex without sterile cell. 

Habitat. Mostly on rocks, sometimes on shells, 

and also epizoic on the sand dollar, Encope grandis L. Agassiz 

(1840); usually in protected bays and estuaries; mid intertidal to 

shallow subtidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Guaymas. Eastern Pacific: southeast 

Alaska to northern Baja California; Peru; Chile. 

FIGURE 133. Neosiphonia paniculata: Habit (JN-4552, US Alg. 

Coll.-160578).
274 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Type Locality. Intertidal, on Ulva nematoidea; Peru.

Remarks. The occurrence of both tetrasporangia 

and cystocarps on the same individual thallus of Neosiphonia 

paniculata from northwestern Baja California was reported by 

R. Aguilar-Rosas and Aguilar-Rosas (1984, as “P. paniculata”). 

Specimens from Laguna Agiabampo referred to “Polysiphonia

aff. paniculata” by Ortega et al. (1987) may also be this species.

Polysiphonia Greville

Polysiphonia Greville, 1823: pl. 90, nom. cons.; M.-S. Kim et al., 2000:83; 

H.-G. Choi et al., 2001a:1465.

Algae are usually erect (flaccid to semirigid) or partially 

erect and prostrate or rarely entirely prostrate axes and mostly 

indeterminate branches of cylindrical, polysiphonous filaments 

composed of segments of an axial cell with four or more pericentral cells (up to 25 or more), the same length as the axial cells. 

Upper portion of the branches are usually straight, with a conspicuous apical cell and forming exogenous branches. Branches 

may develop endogenously adventitiously from various parts of 

the thallus or from scar cells on older parts of branches (cicatrigenous development). Thalli may be uncorticated throughout or 

have some degree of rhizoidal or pseudoparenchymatous cortication formed from the pericentral cells. Erect upper portions 

are developed from a creeping, usually extensive, base of prostrate axes that are attached to substratum by usually unicellular 

rhizoids developed from and remaining in open communication 

with basal pericentral cells. Secondary prostrate branches can 

develop from the attaching decumbent branches or determinate 

attaching branches. Trichoblasts are rare or lacking, and if present, they are colorless (lacking chloroplasts), usually branched 

once to many times, and deciduous, often soon after formation, 

leaving scar cells. Scar cells result from the breaking off of a 

deciduous trichoblast that leaves behind its embedded basal cell.

Asexual propagation is possibly by fragmentation, and asexual propagules have been noted for a few of the species (Kapraun, 

1977; Womersley, 1979). Tetrasporophytes and gametophytes 

are isomorphic. Tetrasporangia are tetrahedrally divided, with 

one per segment in a straight series usually in the upper portion 

of determinate branches. Gametangial thalli are usually dioecious. Carpogonial branch is four-celled, borne on polysiphonous branches. Cystocarps are surrounded by a pericarp of small 

cells, ostiolate and usually borne in upper portions of branches. 

Carposporangia are produced on short gonimoblast filaments 

emerging from a fusion cell. Spermatangial stichidia are elongate 

or cylindrical and develop from a lateral branch initial in upper 

portions of branches, with apices that either lack sterile cells or 

have one to a few sterile terminal cells.

Generitype. Polysiphonia urceolata (Lightfoot ex 

Dillwyn) Greville, 1824:309; basionym: Conferva urceolata

Lightfoot ex Dillwyn, 1809: pl. G (now a synonym of Polysiphonia stricta (Dillwyn) Greville, 1824:309; basionym: Conferva 

stricta Dillwyn, 1804: pl. 40).

Remarks. Species of Polysiphonia can be epiphytic on 

other algae, sea grasses, or other aquatic vegetation, epizoic on sea 

turtles, or grow on rocks or other hard substratum from the intertidal to subtidal. Polysiphonia differs from Neosiphonia in having 

lateral branch development separated by one or more polysiphonous segments, erect determinate and indeterminate branches that 

develop from an extensive creeping base, attachment rhizoids that 

are in open communication with their pericentral cell, trichoblasts 

that are rare or lacking, a four-celled carpogonial branch, spermatangia that develop from a lateral branch initial, and tetrasporangia in straight series in determinate branches.

Some Polysiphonia species with numerous pericentral cells 

per segment are also seemingly close to the eastern Atlantic Leptosiphonia Kylin (1956), a genus separated primarily by its two tetrasporangia per segment. Comparative studies of the generitype, 

L. schousboei (Thuret) Kylin (basionym: Polysiphonia schousboei

Thuret, in Bornet and Thuret, 1876), are needed to clarify its generic status. The relationship of the genus Polyochetum Chevallier 

(1836), considered congeneric with Polysiphonia (see Farr et al., 

1979; Wynne and Schneider, 2010), should also be reinvestigated.

There are six taxa reported in the southern Gulf: Polysiphonia bifurcata Hollenberg (in Taylor, 1945), P. decussata Hollenberg (1942b), P. hendryi N. L. Gardner (1927f), P. homoia

Setchell et N. L. Gardner (1930), and P. pacifica var. gracilis

Hollenberg (1942b) from Bahía de La Paz (Huerta-Múzquiz and 

Mendoza-González, 1985); P. nathanielii Hollenberg (1958a) 

from Jalisco (near the entrance to the Gulf) and Colima (SentíesG., 1995); and, with a taxonomic query, P. scopulorum Harvey 

(1855) from Mazátlan (Mendoza-González et al., 1994).

Six taxa, including five species and three varieties of Polysiphonia are currently recognized in the northern Gulf of California.

KEY TO THE SPECIES OF POLYSIPHONIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Trichoblasts in general very rudimentary or absent; scar cells regularly 1 per segment . . . . . . . . . . . . . . . P. hollenbergii

1b. Trichoblasts and scar cells either lacking or, if present, not regularly 1 per segment . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Thalli delicate; mostly intertidal; mostly forming spreading mats or furry patches . . . . . . . . . P. scopulorum var. villum

2b. Thalli not as delicate; mostly subtidal, not forming mats or patches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Thalli up to 4 cm high; trichoblasts numerous, arising at irregular intervals . . . . . . . . . . . . . . . . . . . . . . . . P. sonorensis

3b. Thalli 2–4 or more than 10 cm tall; trichoblasts infrequent to rare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Thalli 10–30 cm tall; 100–300 μm in diameter; segments mostly 4–10 times longer than diameter . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. pacifica var. pacifica

4b. Thalli shorter, 2–4 cm tall; 50–130 μm in diameter; segments much shorter, 1–3 times longer than diameter . . . . . . . . 5
NUMBER 96 • 275

5a. Thalli short, usually less than 2 cm tall; axes 50–110 μm in diameter, segments 1.0–2.0(–3.0) times longer than diameter 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. pacifica var. delicatula

5b. Thalli taller, up to 4 cm tall; middle portions of axes 70–130 μm in diameter, segments 1–2 times longer than diameter 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. subtilissima

Polysiphonia sect. Oligosiphonia J. Agardh 

Polysiphonia sect. Oligosiphonia J. Agardh, 1863:910. 

Members of this section are characterized by having four 

pericentral cells per polysiphonous segment. 

The five species of Polysiphonia currently known in the 

northern Gulf of California are members of this taxonomic section (=“Polysiphonia group” of H.-G. Choi et al., 2001a). 

Polysiphonia hollenbergii J. N. Norris, sp. nov.

FIGURE 134

Polysiphonia sp. of Hollenberg and Norris, 1977:18 [in part], figs. 10A,B 

(only).

Latin Description. Algae a 3 cm alta; segmentae cellule pericentrales 4 ecorticatae, aeque 1.0–1.5 longa ac 

diametros; axes erectis 320 μm diametro; ramosis saepenumero 

subdichotomous; trichoblastae rudimenta ipsa o absentis, at segmenta irregulariter interpositis de cerca 8–10 segmenta; cellulis 

constans cicatriceum unum segmentum per spiralis sequence; 

non servati rhizoideas; tetrasporangia et cystocarpum invisus; 

stichidia spermatangia totum de integro primoedium trichoblast.

Algae up to 3 cm tall; polysiphonous segments of 4 pericentral cells, 1.0–1.5 times as long as the diameter, uncorticated. 

Main axes up to 320 μm in diameter in lower portions; branching repeatedly subdichotomous at irregular intervals of mostly 

8–10 segments. Rhizoids unicellular, in open communication 

with basal pericentral cells. Trichoblasts very rudimentary or absent; if present, soon deciduous leaving a scar cell.

Tetrasporangia and cystocarps not seen. Spermatangial 

stichidia arising from an entire trichoblast primordium.

Habitat. Epiphytic on other algae; shallow subtidal, 

about 7.6 m depth.

Distribution. Gulf of California: Isla la Ventana, 

Bahía de Los Ángeles.

Holotype. JN-2998b, ♂ (US Alg. Coll. microscope 

slide 5004). Isotype: JN-2998b, ♂ (US Alg. Coll. microscope 

slide 5003).

Type Locality. Isla la Ventana, Bahía de Los Ángeles, Baja California, Gulf of California, Mexico.

Etymology. It is my pleasure to name this species in 

honor of George J. Hollenberg (1897–1988, Professor, University of Redlands; Abbott, 1989) in recognition of his numerous 

phycological contributions, especially the detailed morphological studies of Pacific Polysiphonia, including those of Baja California and the Gulf of California, and studies of the California 

marine flora, most notably the Marine Algae of California (with 

I. A. Abbott). As a beginning student of the marine algae, I was 

introduced to “Uncle George” Hollenberg by “Izzie” Abbott 

(Professor Isabella Aiona Abbott, 1919–2010; Huisman and 

Norris, 2004). It was “Uncle George” who encouraged and fostered my interest in the genus.

Remarks. The development of spermatangia from a 

lateral branch initial (replacing a trichoblast primordium ) was 

observed in the holotype specimen of Polysiphonia hollenbergii

(JN-2998b, ♂; see Hollenberg and Norris, 1977: figs. 10A, B, as 

“Polysiphonia sp.”). Although only a few attachment rhizoids 

were observed, they were unicellular and remain in open communication with basal pericentral cells (JN-2998b; US Alg. Coll. 

microscope slide 5003). Both of these features are characteristics 

of the genus Polysiphonia.

There is another specimen from a different northern Gulf 

locality that was also referred to as “Polysiphonia sp.” (Hollenberg and Norris, 1977:16): a tetrasporophyte, epizoic on a 

pen shell from Bahía San Francisquito; (JN-3265b; US Alg. Coll. 

slide 5016; Hollenberg and Norris, 1977: figs. 10C, D) that has 

 FIGURE 134. Polysiphonia hollenbergii: Upper portion of axes 

with spermatangial stichidia; trichoblasts rare to absent (holotype: 

JN-2998b, US Alg. Coll. microscope slide 5004).
276 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

a spiral arrangement of the tetrasporangia, suggesting that this 

specimen is a different species. It may also be new and probably 

belongs to Neosiphonia.

Polysiphonia pacifica var. delicatula Hollenberg

FIGURE 135

Polysiphonia pacifica var. delicatula Hollenberg, 1942b:778; Smith, 

1944:360; Dawson et al., 1960b:13; Hollenberg, 1961:362; Dawson, 

1961b:450; Abbott and Hollenberg, 1976:690; Hollenberg and Norris, 1977:10, fig. 6b; Young and Kapraun, 1985: figs. 23–28; HuertaMúzquiz and Mendoza-González, 1985:54; Mendoza-González and 

Mateo-Cid, 1985:32; Stewart, 1991:166; Mateo-Cid and MendozaGonzález, 1992:23; Serviere-Zaragoza et al., 1993a:484; MendozaGonzález et al., 1994:109; González-González et al., 1996:255; 

Mendoza-González and Mateo-Cid, 1996b:69, pl. 14: figs. 56–58; 

L. Aguilar-Rosas et al., 2000:132; CONANP, 2002:139; PachecoRuíz and Zertuche-González, 2002:469; Dreckmann et al., 2006:155; 

Pacheco-Ruíz et al., 2008:213.

Algae erect, usually 0.5–2.0 cm tall; uncorticated polysiphonous segments of 4 pericentral cells, (50–)60–110 μm in diameter, 

1.0–2.0(–3.0) times as long as wide; attached by rhizoids, 1 per 

segment from pericentral cells of prostrate branches; rhizoids not 

cut off from the pericentral cell by a cross wall. Erect branches develop endogenously from prostrate branches; all branches indeterminate, short and mostly blunt; often with more or less forcipate 

apices. Trichoblasts lacking or exceedingly rare.

Tetrasporangia 50–60 μm in diameter; in straight series of 

upper branches. Cystocarps slightly urceolate, 200–500 μm in diameter. Spermatangial stichidia developing from entire trichoblast 

primordium; slender, 140–200 μm long by 30–40 μm in diameter; 

on very short pedicels, leaving persistent scar cells when shed. 

Habitat. Epiphytic on various algae and growing on 

rocks or other hard substratum; low intertidal to shallow subtidal. 

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas; San Felipe to Bahía de San Lucas; Mazátlan, Sinaloa 

to Nayarit. Eastern Pacific: Alaska; Oregon to Baja California; 

Santa Catalina Island (California Channel Islands); Chiapas; Galápagos Islands.

Type Locality. On wharf piling, low tide level; 

Monterey Municipal Wharf, Monterey, Monterey County, central California, USA.

Remarks. Polysiphonia pacifica var. delicatula differs from the other varieties in being the smallest (less than 2 

cm tall) and in having narrow main branches (60–100 μm in 

FIGURE 135. Polysiphonia pacifica var. delicatula: A. Trichoblasts rare or lacking on branch apices (after Hollenberg and 

Norris, 1977: fig. 6B). B. Rhizoids remaining in open connection to pericentral cell (A, B, JN-4848a, US Alg. Coll. microscope slide 4260).
NUMBER 96 • 277

diameter). Polysiphonia pacifica var. delicatula is not to be confused with another taxon that bears the same name, the tropical 

P. delicatula Hollenberg (1968a). The latter is a different species that was later described from Hawaii (Hollenberg, 1968a; 

Abbott, 1999) and has since been reported from Micronesia 

(Lobban and Tsuda, 2003) and in the Indian Ocean from the 

Seychelles (Silva et al., 1996a).

Polysiphonia pacifica Hollenberg var. pacifica

Polysiphonia pacifica Hollenberg, 1942b:777, figs. 2–3, 12(type specimen)–13; Smith, 1944:359, pl. 94: fig. 3; Hollenberg, 1961:361, pl. 5: 

fig. 5, pl. 7: figs. 2–3; Dawson, 1961b:450; Abbott and Hollenberg, 

1976:689, fig. 637; Silva, 1979:331; Mendoza-González and MateoCid, 1985:32; Huerta-Múzquiz and Mendoza-González, 1985:54; 

L. Aguilar-Rosas et al., 1985:125; Mendoza-González and Mateo-Cid, 

1986:421; Scagel et al., 1989:233; Mendoza-González et al., 1994:109; 

Anaya-Reyna and Riosmena-Rodríguez, 1996:864 (tbl. 1); GonzálezGonzález et al., 1996:255; M.-S. Kim and Yang, 2005:17, figs. 5–8; 

Pérez-Estrada et al., 2012:191.

Algae of erect axes, (5–)10–25 cm tall, and less conspicuous lower creeping axes; main axes little branched; branching 

more or less alternate, up to several orders; branch intervals of 

(2–)4–5 segments but often longer between branches; polysiphonous segments of 4 pericentral cells, uncorticated, 100–300 μm 

in diameter, 4–10(–20) times as long as wide (shorter in ultimate 

branchlets); lower prostrate portions attached by unicellular rhizoids issued from center of lower pericentral cells at irregular 

intervals and not cut off by cross walls. Trichoblasts and scar 

cells absent or exceedingly rare. 

Tetrasporangia 60–70 μm in diameter in straight series 

within ultimate branchlets. Cystocarps slightly urceolate, 200–

500(–675) μm in diameter; on an inconcpicuous to very short 

pedicel. Spermatangial stichidia, cylindrical, with apices of one 

to several sterile cells; developed from lateral branch initial. 

Habitat. Usually found growing in lagoons and 

esteros; on rocks and shells, and epiphytic of mangroves (on 

pneumatophores of Avicennia germinans and aerial roots of Rhizophora mangle) and probably other algae; intertidal to shallow 

subtidal.

Distribution. Gulf of California: Punta Chueca to 

Estero Santa Rosa, Sonora; Estero Zacatecas (Ensenada de La 

Paz) to Bahía La Paz; Cabo Pulmo to Punta Los Frailes; Mazátlan. Eastern Pacific: Alaska to central California; Islas Coronados; 

Las Playitas, Ensenada to estero Punta Banda, Baja California; El 

Salvador. 

Type Locality. Santa Cruz, Santa Cruz County, 

central California.

Remarks. Polysiphonia pacifica var. pacifica (Hollenberg, 1942b) has been reported in the northern Gulf by 

Mendoza-González and Mateo-Cid (1986). Since I have not seen 

their specimens, the description is based on Hollenberg (1961). 

Polysiphonia pacifica var. pacifica is much larger than those of 

the northern Gulf P. pacifica var. delicatula,10–25 cm tall, with 

axes 100–200(–300) μm in diameter, and with segments much 

longer than wide. 

Polysiphonia pacifica is considered to be a highly variable 

species, with six varieties, including P. pacifica var. pacifica, recognized (Hollenberg, 1942b; Abbott and Hollenberg, 1976; Gabrielson et al., 2004). M.-S. Kim and Yang (2005: fig. 13) found 

that although one of the varieties, the Pacific Northwest P. pacifica var. disticha Hollenberg (1942b), differed morphologically, 

it had identical rbcL sequences, clustering with P. pacifica var. 

pacifica. Polysiphonia pacifica has also been reported from El 

Salvador (Avilés and Canjura, 1979; Fernández-García et al., 

2011) and Chile (Hoffmann and Santelices, 1997), but without 

noting their varietal identifications.

Polysiphonia scopulorum var. villum (J. Agardh) Hollenberg

FIGURE 136

Polysiphonia villum J. Agardh, 1863:941. 

Polysiphonia scopulorum var. villum (J. Agardh) Hollenberg, 1968a:81, 

fig. 7a; Abbott and Hollenberg, 1976:692, fig. 640; Hollenberg and 

Norris, 1977:14, fig. 8b; Santelices and Abbott, 1978:219; Kapraun 

and Norris, 1982:233, fig. 111a–b; Schnetter and Bula-Meyer, 

1982:175, pl. 32: figs. M,N; Stewart and Stewart, 1984:147; HuertaMúzquiz and Mendoza-González, 1985:54; Young and Kapraun, 

1985:113, figs. 35–40; Santelices and Abbott, 1987:9; Santelices, 1989:369, pl. ÑÑ: fig. 19; Stewart, 1991:167; León-Tejera 

et al., 1993:200; R. Aguilar-Rosas and Aguilar-Rosas, 1994:524; 

González-González et al., 1996:324; Mendoza-González and MateoCid, 1996b:69, pl. 15: figs. 59–63; M.-S. Kim and Lee, 1996:143; 

Hoffman and Santelices, 1997:397, figs. 112:1–7; Mateo-Cid et 

al., 2000:67; Riosmena-Rodríguez et al., 2005a:34; Dreckmann et 

al., 2006:155; Pacheco-Ruíz et al., 2008:213; R. Aguilar-Rosas and 

Aguilar-Rosas, 2010:187, fig. 1; Fernández-García et al., 2011:63; 

Pérez-Estrada et al., 2012:191.

Lophosiphonia villum (J. Agardh) Setchell et N. L. Gardner, 1903:329; 

Kylin, 1941:40; Hollenberg, 1942a:535; Dawson, 1944a:332, pl. 

48: figs. 1–6; Smith, 1944:364, pl. 94: fig. 1; Taylor, 1945:304; Dawson, 1954b:161; 1963b:421, pl. 169: figs. 1–3; Stewart and Stewart, 

1984:147; Serviere-Zaragoza et al., 1993a:484; González-González et 

al., 1996:243.

Algae to 5–10 mm high, composed of uncorticated polysiphonous axes with segments of 4 pericentral cells around a 

central axial filament cell; prostrate system well developed; erect 

axes sparingly branched or unbranched, arising at irregular 

intervals in a strictly endogenous manner from prostrate axes 

attached by unicellular rhizoids developed from center of the 

pericentral cells and not cut off by cross walls. Branch segments 

usually 40–60 μm in diameter and 1.0–1.5 times as long as wide. 

Lateral branches on erect axes, if present sparse, exogenous or 

endogenous, independent of trichoblasts. Trichoblasts usually infrequent or lacking; if present, with 1 or 2 dichotomies, 250–480 

μm long; soon deciduous.

Tetrasporangia 50–60 μm in diameter; in straight series, 

somewhat distending the segments. Cystocarps ovoid, 150–190 

μm in diameter. Spermatangial stichidia cylindrical, without sterile apices; arising from an entire trichoblast primordium. 

Habitat. On rocks and shells and on tidal platforms; 

intertidal.
278 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Distribution. Gulf of California: Puerto Peñasco; 

Isla Ángel de la Guarda; Isla Partida; Isla Turner (Turners); Isla 

Estanque; Punta Arena to Cabo Pulmo; Nayarit. Eastern Pacific: 

Kodiak Island, Alaska to Oregon; central California to Baja California Sur; Santa Catalina Island (California Channel Islands); 

Isla Guadalupe; Chiapas to Costa Rica; Colombia; Chile; Rapa 

Nui (Easter Island; Isla de Pascua). 

Type Locality. “Ad littus americae tropicae” 

(J. Agardh, 1863); Dawson (1944a:333) stated “probably on the 

central coast of [Pacific] Mexico.” 

Remarks. Originally described as a species of Polysiphonia, P. villum J. Agardh (1863) was later transferred to 

the genus Lophosiphonia Falkenberg (in F. Schmitz and Falkenberg, 1897), where it was recognized as L. villum (e.g., Dawson, 

1944a, 1963b; Smith, 1944) until Hollenberg (1968a) considered it to be one of three taxonomic varieties of Polysiphonia 

scopulorum. One of these, P. scopulorum var. villum, is found 

in the northern Gulf (Hollenberg and Norris, 1977) and California (Abbott and Hollenberg, 1976; Young and Kapraun, 1985). 

Polysiphonia scopulorum var. villum primarily differs from the 

other varieties in having segments of the branches that are mostly 

longer than wide. Masuda et al. (2000) observed similarities between their Malaysian P. scopulorum var. scopulorum and P. 

scopulorum var. villum and suggested these two varieties were 

the same. Cystocarps and tetrasporangia have been reported 

on the same thallus of Pacific Mexico P. scopulorum var. villum

from northern Baja California (R. Aguilar-Rosas and AguilarRosas, 2010). Herein the northern Gulf specimens are referred 

to P. scopulorum var. villum until its generic and specific status is 

clarified by comparisons with the types and type locality materials of these taxonomic varieties. 

Polysiphonia sonorensis Hollenberg

FIGURE 132F

Polysiphonia sonorensis Hollenberg, 1942b:779, figs. 5, 20; Dawson, 

1944a:330; 1954d:161; Hollenberg, 1961:365, pl. 5: fig. 2, pl. 6: 

fig. 1; Dawson, 1961b:450; Huerta-Múzquiz and Tirado-Lizárraga, 

1970:129; Hollenberg and Norris, 1977:16, fig. 2c; González-González 

et al., 1996:257; Serviere-Zaragoza et al., 2007:11.

Algae erect, usually dense tufts of filaments; up to 5 cm 

high, terracotta color (not strongly adherent to herbarium paper 

on drying); erect main axes indistinct usually densely branched; 

polysiphonous segments of 4 pericentral cells, uncorticated, 70–

100 μm in diameter, mostly 1.5–2.0 times as long as the diameter; 

above prostrate, creeping branches, 120–175 μm in diameter; 

attached by unicellular rhizoids developed from center of the 

FIGURE 136. Polysiphonia scopulorum var. villum: A. Axes with a branched trichoblast (JN-5098a, US Alg. Coll. microscope slide 4995). 

B. Prostrate axes with rhizoids in open communication with pericentral cell (JN-3744, US Alg. Coll. microscope slide 5025). 
NUMBER 96 • 279

pericentral cells and not cut off as separate cells. Erect branches 

usually develop endogenously or sometimes exogenously from 

the prostrate branches; exogenously produced branches at irregular intervals of mostly 1–20 segments, usually at an acute 

angle with the parent branch; branches replacing trichoblasts. 

Trichoblasts delicate, numerous, up to 1 mm long, with 1 or 2 

dichotomies arising at irregular intervals; deciduous, leaving inconspicuous scar cells.

Reproductive material has not been found.

Habitat. On rocks; intertidal.

Distribution. Gulf of California: Guaymas to the 

bay (bahía) near Empalme.

Type Locality. “Afloat,” southeastern shore of the 

bay, near Empalme, Sonora, Gulf of California, Mexico (Hollenberg, 1942b). 

Remarks. As a little-known species, more collections 

of Polysiphonia sonorensis, particularly reproductive specimens, 

are needed to determine its taxonomic status. It has also been 

reported from the Golfo de Tehuantepec, Oaxaca (HuertaMúzquiz and Tirado-Lizárraga, 1970), and Isla Socorro, Islas 

Revillagigedo (Huerta-Múzquiz and Garza-Barrientos, 1975; 

Serviere-Zaragoza et al., 2007). 

Polysiphonia subtilissima Montagne

Polysiphonia subtilissima Montagne, 1840:199; Taylor, 1947:86; Dawson 

et al., 1964:90, pl. 80: figs. G–J; Ramírez and Santelices, 1991:379; 

Sheath et al., 1993:115, figs. 19–21; Sentíes-G., 1995:50, figs. 37–44; 

Abbott, 1999:430, fig. 128A; Mateo-Cid et al., 2006:57; Dreckmann et 

al., 2006:155; Bernecker, 2009:CD-Rom p. 68; Fernández-García et al., 

2011:64; Lam et al., 2013:156, figs. 1–6.

Polysiphonia subtilissima var. abbottiae Hollenberg, 1968a:92, figs. 5F, 6A.

Algae up to 4 cm tall; polysiphonous filaments uncorticated, with 4 pericentral cells per segment; erect portions above 

prostrate axes; attachment rhizoids, unicellular, with lobed tips, 

remain in open connection with pericentral cells. Erect axes endogenous, slender, 70–130 μm in diameter in middle portions; 

about 50 μm in diameter in upper branches; pericentral cell segments 1–2 times longer than diameter. Lateral branches develop 

independent of trichoblasts at varying intervals. Trichoblasts 

infrequent, with 1–2 dichotomies; usually poorly developed (occasionally up to 400 μm long). 

Reproductive structures not reported in the northern Gulf.

Habitat. On tidal rocks, aquatic vegetation, and 

mangroves in shallow esteros and bays; intertidal.

Distribution. Gulf of California: Punta Pelícano 

(vicinity of Puerto Peñasco). Eastern Pacific: Chiapas; El Salvador; Costa Rica; Peru. Central Pacific: Oahu, Hawaiian Islands. 

Western Pacific: Korea; Vietnam.

Type Locality. Cayenne, Arrondissement of Cayenne, French Guiana (Guyane).

Remarks. Polysiphonia subtilissima is only known 

in the upper Gulf of California from the report of Mateo-Cid et 

al. (2006). Since I have not seen their material, the description 

herein follows Abbott (1999) and Womersley (2003). Apparently 

widely distributed, P. subtilissima has been reported in the Mediterranean Sea, Eastern and Western Atlantic (including the Caribbean Sea), Eastern and Western Pacific, and Indian Oceans 

(e.g., Adams, 1991; Silva et al., 1996a; John et al., 2004; Suárez, 

2005; Wynne, 2005; Mamoozadeh and Freshwater, 2012; Guiry 

and Guiry, 2012). Also physiologically very tolerant, P. subtilissima has been reported in a wide range of habitats including 

brackish waters in Hawaii (Abbott, 1947), freshwater in Florida 

(Sheath and Cole, 1990; Sheath et al., 1993), and in shallow bays 

and low intertidal rocks on marine shores (Womersley, 2003). 

Lam et al. (2013) recently confirmed that freshwater collections 

from Spain, Jamaica, and Florida were the same as P. subtilissima from marine habitats. Different taxonomic treatments that 

include “P. subtilissima” have given varying descriptions of the 

taxon, suggesting some may be misidentified or there may be 

more than one species. Mamoozadeh and Freshwater (2012) 

found three genetic species that had only slight morphological 

differences but were in general agreement with a broadly defined 

“P. subtilissima.” Thus further studies are needed to determine if 

there are any cryptic or overlooked species within those referred 

to “P. subtilissima.”

Rhodomelaceae tribus Pterosiphonieae

Rhodomelaceae tribus Pterosiphonieae Falkenberg, 1901:261.

The tribe is represented by two of its genera in the northern 

Gulf of California.

Pterosiphonia Falkenberg in 

F. Schmitz and Falkenberg

Pterosiphonia Falkenberg in F. Schmitz and Falkenberg, 1897:443.

Thalli are erect, bilaterally branched, terete to strongly 

compressed axes that arise from indeterminate prostrate, mostly 

terete, rhizome-like axes. Rhizoids cut-off from prostrate axes 

form multicellular discs that adhere to substratum. Axes are 

polysiphonous and uncorticated or corticated, with segments 

composed of an axial filament cell surrounded by 4–20 pericentral cells, and lateral indeterminate axes replacing or developing 

from determinate axes. Axes are distichously branched from 1 

to several orders, alternately arranged, laterals emerging every 

2–4 segments. The basal portion of each branch is coalesced 

(fused) with its parental axis for 1 to a few segments. Ultimate 

branchlets are determinate and may be simple or pinnately 

branched and generally lack vegetative trichoblasts. Cells are 

uninucleate.

Asexual reproduction by fragmentation has been reported. 

Tetrasporangia are tetrahedrally divided and 1 per segment in a 

straight series in the determinate laterals. Gametophytes are dioecious, procarps and spermatangial structures borne on modified trichoblasts. Cystocarps are globular to ovoid, borne on 

short stalks on determinate laterals. Spermatangial stichidia are 

in alternate distichous arrangement or spirally arranged, forming 

clusters at apices of determinate branchlets or on short, spur-like 
280 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

branchlets from the ultimate determinate branchlets, borne on 

suprabasal cell of a modified trichoblast.

Two species of Pterosiphonia are known in the northern 

Gulf of California.

KEY TO THE SPECIES OF PTEROSIPHONIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli small, up to 2.5 cm high, main axes only slightly compressed, with few branches; base of branches coalesced with 

bearing axis for 1.5 proximal segments; lateral branchlets cylindrical, mostly simple, sometimes with incurved ultimate 

branchlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. californica

1b. Thalli usually larger, markedly compressed throughout; with numerous branches; base of branches coalesced with bearing axis for 2–2.5 proximal segments; lateral branchlets compound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. dendroidea

Pterosiphonia californica Kylin

FIGURE 137B

Pterosiphonia californica Kylin, 1941:39; Hollenberg, 1948:160; Dawson, 

1961b:452. 

Pterosiphonia pennata sensu Dawson, 1944a:334; 1961b:452; 1963b:427; 

Abbott and Hollenberg, 1976:708, fig. 660; R. Aguilar-Rosas, 1982:84; 

Pacheco-Ruíz and Aguilar-Rosas, 1984:74; L. Aguilar-Rosas et al., 

1985:125; Mendoza-González and Mateo-Cid, 1985:32; R. AguilarRosas and Machado-Galindo, 1990:188; Stewart, 1991:169; GonzálezGonzález et al., 1996:263; CONANP, 2002:139 [non Pterosiphonia 

pennata (C. Agardh) Sauvageau, 1897:287; basionym: Hutchinsia pennata C. Agardh, 1824:156].

Algae mostly 1.0–2.5 cm tall, 125–140(–200) μm in diameter; 

uncorticated, polysiphonous segments of 8–11(–12) pericentral 

cells. Erect axes percurrent, distichously and alternately branched; 

axes slightly compressed, arise above prostrate axes at every third 

segment. Branchlets cylindrical, 1.0–1.5 mm long, mostly simple, 

and usually slightly incurved, arising from every second segment.

Tetrasporangia in upper portion of determinate branchlets, 

in a series with 1 per segment. Cystocarps not seen in Gulf material. Several spermatangial stichidia, each on modified trichoblast primordium; borne distichous or adaxially, near apices of 

ultimate determinate branches.

Habitat. On rocks or occasionally epiphytic; intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas; Cabeza Ballena to Cabo San Lucas. Eastern Pacific: 

southern California to northern Baja California.

Type Locality. La Jolla, San Diego County, southern California, USA.

Remarks. Dawson (1944a, as Pterosiphonia pennata) initially considered his northern Gulf (Bahía Tepoca, 

EYD-372) specimen to be different from the southern California Pterosiphonia californica. But later Dawson (1963b) placed 

P. californica in synonymy with the Mediterranean P. pennata,

stating the size differences noted by Kylin (1941) were not 

enough to keep them as separate species. More recently, Uwai 

and Masuda (1999b:248, tbl. 1) noted that the marked disjunct 

distribution between the two requires further consideration. 

Until detailed comparative morphological and genetic studies 

can be done on the northern Gulf P. californica and type localities of the California P. californica and the Mediterranean P. pennata, I herein follow their suggestion that they may be separate 

species.

The taxon has often been incorrectly cited as “Pterosiphonia 

pennata (Roth) Falkenberg, 1901.” However there are nomenclatural problems with the basionym. Silva et al. (1996a:549) 

noted Ceramium pennatum Roth (1806) is to be treated as new 

species, but since that name is a later homonym of Ceramium 

pennatum (Hudson) Roth (1800; basionym: Conferva pennata

Hudson, 1762) it is illegitimate. However, Hutchinsia pennata

C. Agardh (1824) can be treated as a new name (ICBN, Art. 

58.3) and is the correct basionym of Pterosiphonia pennata

(C. Agardh) Sauvageau (Silva et al., 1996a). Although Conferva 

pennata Hudson also had been treated earlier as basionym of 

Sphacelaria pennata, that use was rejected by Prud’homme van 

Reine (1982; see also Dixon and Parkes, 1968).

Pterosiphonia dendroidea (Montagne) Falkenberg

FIGURE 137A

Polysiphonia dendroidea Montagne, 1837:353.

Pterosiphonia dendroidea (Montagne) Falkenberg, 1901:268; Howe, 

1914:144; Kylin, 1941:39; Dawson, 1944a:335; Smith, 1944:366, 

pl. 95: fig.3; Taylor, 1945:304, pl. 96: fig. 2; Dawson et al., 1960a:76, 

pl. 41: figs. 3, 4; Dawson, 1961b:452; 1963b:426, pl. 157: fig. 2; 

Dawson et al., 1964:84, pl. 69: fig. B; Dawson, 1966a:29; Norris, 1973:16; Abbott and North, 1972:76; Abbott and Hollenberg, 

1976:708, fig. 659; Pacheco-Ruíz and Aguilar-Rosas, 1984:74; 

Stewart and Stewart, 1984:147; Mendoza-González and MateoCid, 1985:32; L. Aguilar-Rosas et al., 1985:125; Sánchez-Rodríguez 

et al., 1989:46; Scagel et al., 1989:248; R. Aguilar-Rosas and 

Machado-Galindo, 1990:188; Aguilar-Rosas et al., 1990:126; Stewart, 1991:168; Ramírez and Santelices, 1991:380; R. Aguilar-Rosas 

and Aguilar-Rosas, 1994:524; Mateo-Cid and Mendoza-González, 

1994b:42; González-González et al., 1996:263; Hoffman and Santelices, 1997:400, fig. 113; L. Aguilar-Rosas et al., 2000:132; PachecoRuíz and Zertuche-González, 2002:469; Riosmena-Rodríguez et al., 

2005b:34; Hernández-Herrera et al., 2005:148; Mateo-Cid et al., 

2006:57; Pacheco-Ruíz et al., 2008:213; Castañeda-Fernández de 

Lara et al., 2010:200.

Algae 2–8 cm tall; of main axes 200–500 μm wide, gradually attenuating upward; uncorticated, markedly compressed, 

polysiphonous segments of 8–12 pericentral cells, segments of 

main axis typically broader than long. Erect axes percurrent, 

distichously and alternately branched up to 3 orders, generally 

at intervals of 2.0–2.5 segments; arising from prostrate axes, attached by groups of unicellular rhizoids issued from pericentral 
NUMBER 96 • 281

cells. Lateral branches compound, with determinate branchlets, 

all of nearly same length (0.5–1.3 mm long).

Tetrasporangia spherical, 60–70 μm in diameter, 1 per segment in straight series in determinate branchlets. Cystocarps not 

seen in Gulf of California specimens. Spermatangial stichidia on 

1-celled pedicels (unbranched modified trichoblasts), up to 150 

μm long, incurved, with 1 to a few sterile terminal cells; arising 1 

per segment near tips of indeterminate axes.

Type Locality. Callao (city), Bahía Callao, Provincia Callao, Peru.

Habitat. Among algal turfs on rocks, on tidal platform, and in tide pools or epiphytic; intertidal.

Distribution. Gulf of California: Playa Tucson 

and Playa Las Conchas (Playa Estación), Puerto Peñasco to 

Guaymas; Puerto Refugio, Isla Ángel de la Guarda, and Isla Tiburón (Islas de la Cintura); San José del Cabo; Jalisco. Eastern 

Pacific: Alaska to Todos Santos, Baja California Sur; Islas Todos 

Santos and Isla Guadalupe, off Baja California; Islas Revillagigedo; Galápagos Islands; Peru; Chile.

Remarks. Dawson (1963b) noted most Gulf Pterosiphonia dendroidea were more lax and clearly percurrent, except 

in the last order of branching, than Pacific Coast specimens.

Pterosiphoniella E. Y. Dawson

Pterosiphoniella E. Y. Dawson, 1963b:422.

Algae of erect, compressed, uncorticated polysiphonous axes 

that arise from creeping, cylindrical axes attached by unicellular 

rhizoids cut off from ventral pericentral cells. Indeterminate axes 

covered with determinate short laterals, the upper portions of 

erect axes are initially multifariously branched (spirally arranged) 

and below the laterals become distichously arranged (bilateral). 

Lateral branches sometimes strictly determinate or may sympodially develop short determinate secondary axes that bear several 

secondary determinate laterals. Vegetative trichoblasts are occasional to abundant at apices. Pericentral segments are mostly of 8 

cells, but a segment can appear to be of 10–16 cells where its parental axis and the proximal segments of laterals are juxtaposed.

FIGURE 137. Species of Pterosiphonia. A. Pterosiphonia dendroidea: Branching pattern and apex (JN-4742, US Alg. Coll. microscope slide 

4899). B. Pterosiphonia californica: Branching pattern and apex (JN-5021, US Alg. Coll. microscope slide 4900).
282 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Tetrasporangia develop 1 per segment, in a straight series 

within determinate lateral branchlets. Gametophytes are presumed to be dioecious, however female reproductive structures 

are unknown. Spermatangial branches are pedicellate, arising 

from an entire trichoblast primordium.

Remarks. Dawson (1963b) observed that Pterosiphoniella shared some characters with both the “Polysiphonia

group” (radially organized) and the “Pterosiphonia group” (bilaterally arranged) sensu Kylin (1956). Comparison of Pterosiphoniella to related genera (i.e., Pterosiphonia; Tayloriella Kylin, 

1938; Boergeseniella Kylin, 1956; Pterochondria Hollenberg, 

1942a; Kintarosiphonia Uwai et Masuda, 1999a) was provided 

by Uwai and Masuda (1999a:225, 233: tbl. 1). Pterosiphoniella

primarily differs from these genera in having vegetative trichoblasts on its apices that are initially radial (spiral) in arrangement 

and later secondarily develop a bilateral habit. 

Described from Pacific Mexico, Dawson (1963b) also observed that North Carolina specimens of Williams (1948, as 

“Pterosiphonia pennata”) may also belong to Pterosiphoniella, suggesting the genus may also occur in the western Atlantic. Dawson (1963b) concluded Pterosiphoniella was closest to 

Pterosiphonia but was distinguished by vegetative trichoblasts 

on the tips of its branches, and the initial multifarious (spiral) 

branching of its erect axes. Later, Wynne (1985d) noted that, 

although rare, vegetative trichoblasts had also been occasionally 

reported in one species of Pterosiphonia, P. pennata (e.g., Ardré, 

1967), and suggested that character may not be enough to separate Pterosiphoniella from Pterosiphonia. Abundant vegetative 

trichoblasts were described on the axes of another species, Pterosiphonia tanakae Uwai et Masuda (1999b). Although recognized 

as distinct by some (e.g., Stewart and Stewart, 1984; GonzálezGonzález et al., 1996; Uwai and Masuda, 1999a, 1999b), these 

two genera were considered congeneric by Schneider and Wynne 

(2007). Another species mentioned by Wynne (1985d), Pterosiphonia fibrillosa Okamura (1912; Yoshida, 1998), was subsequently removed to establish the genus Kintarosiphonia as 

K. fibrillosa (Okamura) Uwai et Masuda (1999a). When female 

reproductive structures of Pterosiphoniella williamsii can be 

found and studied and genetic testing of type locality and Gulf 

specimens can be completed, its taxonomic status and phylogenetic relationships with these genera can be elucidated.

A monotypic genus, its one species occurs in the Gulf of 

California.

Pterosiphoniella williamsii E. Y. Dawson

FIGURE 138

Pterosiphoniella williamsii E. Y. Dawson, 1963b:423, pl. 135: figs. 3, 4, pl. 

160: figs. 1, 2 (holotype); Stewart and Stewart, 1984:147; GonzálezGonzález et al., 1996:263.

Algae up to 2 cm tall, polysiphonous axes and branch segments of mostly 8 pericentral cells, but may appear to be 10–16 

cells where basal segments of a branch are adjacent to their parental axis, with central axial cells of similar size and shape to 

pericentral cells; erect axes compressed, about 300 μm wide; 

covered with determinate short laterals; apices of main axes 

multifariously (radially) branched at intervals of 2–3 segments; 

branch initials developed spirally at tips, soon becoming irregular after first few segments by slight twisting of tip and by bilateral growth of branches, then within 15 segments becoming 

distinctly bilateral. Lateral branches basically determinate, usually develop a new axis sympodially and abaxially that produces 

1–10 secondary short lateral branches, which in turn often develop 1–2 laterals sympodially. Determinate branchlets terete to 

compressed, 300–600 μm long, with subacute tips with a single 

terminal conical cell. Trichoblasts sparse, soon deciduous; or 

absent on most primary axis tips that produce regular lateral 

branches; abundant and densely branched on tips of secondary 

axes and secondary determinate lateral branches.

Tetrasporangia spherical, tetrahedrally divided, 50–60 μm 

in diameter; 1 per segment, in straight series in determinate laterals. Cystocarps unknown. Spermatangial branches borne on 

1-celled pedicel and terminate in a 1- to 2-celled sterile tip. Mature spermatangial branches conical, up to 100 μm or more in 

length (after Dawson, 1963b). 

Habitat. On partially sand covered rocks; low intertidal to shallow subtidal, 2–5 m depths.

Distribution. Gulf of California: Cabeza Ballena. 

Eastern Pacific: Isla Guadalupe; Punta Santa Rosaliita (“Punta 

Santa Rosalía”), Baja California to Laguna Ojo de Liebre (Scammon’s Lagoon), Baja California Sur.

Type Locality. On fine sand and rock bottom, 

dredged at 6 m depth; Isla Concha, Laguna Ojo de Liebre (Laguna de Scammon), Baja California Sur, Pacific Mexico.

Remarks. Collections from Cabeza Ballena, Baja 

California Sur, referred to Pterosiphoniella williamsii represent 

a new record for the Gulf of California (US Alg. Coll.: JN-4103, 

microscope slide 4915; JN-4126, microscope slide 4914; and 

JN-4149, microscope slide 4950). Gulf specimens tentatively 

identified as P. williamsii are only in partial agreement, and they 

differ in having determinate branches that remain multifariously 

arranged, not only in upper portions but also in lower portions 

of axes, and the determinate lateral branches are also multifariously branched, and trichoblasts that are few to rare at apices. 

Spermatangial branches of the Gulf specimens also differ in their 

lack of the 1–2 sterile cells that were noted by Dawson (1963b) 

at the tips of those of Pacific Mexico specimens. Although thus 

far only known in the southern Gulf, P. williamsii is included 

here since it is apparently rare, and this easily overlooked species may be found elsewhere in the Gulf. Molecular analyses of 

Gulf P. williamsii are necessary for comparison with type locality 

specimens to test their taxonomic status and relationship to each 

other and to other related genera.

Tayloriella Kylin

Tayloriella Kylin, 1938:18.

Algae form small turfs or clumps of erect and decumbent, 

cylindrical, uncorticated, polysiphonous axes and branches that 
NUMBER 96 • 283

are composed of 4–16 pericentral cells depending on species (or 

sometimes of variable number on the same thallus). Single-celled 

attachment rhizoids are cut off from the proximal ends of ventral 

pericentrals of prostrate axes in some species, but in others they 

are not cut off. Rhizoids may sometimes be in groups, having 

developed from the pericentrals on the same segment (Wynne, 

1985d). Erect axes can be branched in a zigzag or distichous 

arrangement. Branches are exogenously developed, with branch 

initials at first radially arranged, later becoming bilaterally or 

distichously arranged. Growth is monopodial, often with abaxial determinate laterals extending above parent axes. Branchlets 

are formed in regular sequence, although usually not on every 

segment but at intervals of 2–3(–4) segments. Indeterminate axes 

are irregular, produced in the position of a determinate branch. 

Determinate laterals in some species have monosiphonous portions at their apices. Trichoblasts are absent on the vegetative 

axes in many species, but although sometimes rare, they are present in at least one species (i.e., T. dictyurus). 

Tetrasporangia are tetrahedrally divided, with one per segment, in straight, usually short, series within a tetrasporangial 

branchlet. Reproductive branchlets are developed in the position 

of a determinate lateral. Cystocarps, globose to urceolate, are 

FIGURE 138. Pterosiphoniella williamsii: A. Portion of an indeterminate branch with determinate laterals bearing spermatangial stichidia near 

their apices. B. Upper portion of indeterminate branch. C. Spermatangial stichidia and trichoblasts at apices (A–C, JN-4126, US Alg. Coll. microscope slide 4914). D. Tetrasporangia borne in series, 1 per segment (JN-4103, US Alg. Coll. microscope slide 4915).
284 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

borne terminal on short lateral branchlets. Spermatangial structures are conical with a sterile fork (Uwai and Masuda, 1999a), 

borne on trichoblasts that terminate with one (or more) sterile 

apical cells (after Wynne, 1985d; Abbott, 1999).

One species of Tayloriella has been reported in the northern 

Gulf of California.

Tayloriella dictyurus (J. Agardh) Kylin

Polysiphonia dictyurus J. Agardh, 1847:16.

Tayloriella dictyurus (J. Agardh) Kylin, 1956:505; Dawson, 1961b:421; 

1963b:416, pl. 129: fig. 5, pl. 138: fig. 4; Huerta-Múzquiz and 

Tirado-Lizárraga, 1970:129; Huerta-Múzquiz, 1978:339; Pedroche 

and González-González, 1981:68; Huerta-Múzquiz and MendozaGonzález, 1985:52; Mendoza-González and Mateo-Cid, 1986:426; 

Dreckmann et al., 1990:32, pl. 2: figs. 6–7; Sentíes-G. et al., 1990:101, 

pl. 5; González-González et al., 1996:271; Abbott, 1999:441, fig. 

132A–E.

Bryocladia dictyurus (J. Agardh) W. R. Taylor, 1945:298, pl. 98: fig. 2; 

Dawson, 1954e:345; Hollenberg, 1958a:63; Salcedo-Martínez et al., 

1988:83; González-González et al., 1996:180.

Algae in erect tufts, 1.5–2.0 cm tall, above basal creeping 

axes attached to substrate by haptera; axes of uncorticated, 

polysiphonous segments with an axial filament cell encircled by 

5–10(–12) pericentral cells. Pericentral cells more or less quadrate and short in mid to upper parts, about 50 μm long; in lower 

parts up to 100 μm long (about twice the diameter). Main axes 

simple or occasionally divided, 150–330 μm in diameter, with 

spirally arranged determinate laterals, simple or forked, 0.5–2.0 

mm long, 80–110 μm in diameter at base. Branches exogenous 

or, less frequently, adventitious from the pericentral cells; final 

order of spirally arranged simple branchlets up to 20 segments in 

length; basally to 80–110 μm wide, tapered to unicellular apex. 

Trichoblasts apical, branched, apparently deciduous (description 

after Taylor, 1945; Dawson, 1963b).

Tetrasporangia in series of 6–8, one per segment, in midportions of upper determinate branchlets (after Dawson, 1963b). 

Gametangial reproduction not reported in northern Gulf specimens. Cystocarps in Hawaiian specimens borne on short determinate branchlets, close to the axes in apical portions of thallus. 

Spermatangial branches with basal pedicel, cylindrical, up to 140 

μm long, about 40 μm in diameter near base, slightly tapered 

to blunt apices, about 26 μm in diameter; borne on modified 

trichoblasts, abundant near apices (gametophytes as described 

by Abbott, 1999).

Habitat. Growing on rocks among turf algae; intertidal.

Distribution. Gulf of California: Segundo Cerro 

Prieto (north of Kino Nuevo), Bahía Kino; Jalisco. Eastern Pacific: Guerrero to Oaxaca; El Salvador; Ecuador. Central Pacific: 

Hawaiian Islands.

Type Locality. “Pochetti” (J. Agardh, 1847); “presumably in the Isthmus of Tehuantepec, Oaxaca” (Dawson, 

1963b:417); probably near Pochutla, Oaxaca, Pacific Mexico 

(note that Pochutla is Spanish for the place of “pochotes,” the 

Spanish name for the Mexican tree species of Ceiba, Malvaceae).

Remarks. Tayloriella dictyurus has been recorded 

from Sonora in the northern Gulf of California by MendozaGonzález and Mateo-Cid (1986) and in the southern Gulf from 

La Paz by Huerta-Múzquiz and Mendoza-González (1985). 

Since I have not seen their material, the description is based on 

Dawson (1963a).

Placophora Group

Placophora group sensu Kylin, 1956:497, 528; Womersley, 2003:359.

Members are flattened, foliose, simple or irregularly 

branched, with broad rounded apices; attached by rhizoids from 

the ventral surface. Apices formed by rows of polysiphonous filaments laterally conjoined, each with a terminal apical cell and 5 

pericentral cells, 3 on the dorsal side and 2 on the ventral surface. Thalli ecorticate, mostly 2 cells thick; unicellular or multicellular attachment rhizoids cut off from ventral pericentral cells. 

Remarks. The Placophora group is characterized by 

the dorsiventrally arranged pericentral cells and contains only 

two genera, Amplisiphonia Hollenberg (1939) and Placophora

J. Agardh (1863).

There is one genus, Amplisiphonia, represented in the Gulf 

of California marine flora.

Amplisiphonia Hollenberg 

Amplisiphonia Hollenberg, 1939:380; Hollenberg and Wynne, 1970:175, 

figs. 1–5; Kraft and Wynne, 1992:33.

Algae prostrate, dorsiventral, flat-lobed thallus formed by 

numerous laterally adherent polysiphonous branches; attached 

to the substratum by unicellular rhizoids issued from the ventral 

surface. Lobed thallus uncorticated, often overlapping. Growth 

from apical cells at the margin of the foliose thallus, vegetative 

thalli without trichoblasts, each apical cell cuts off 5 pericentral cells, dorsiventrally arranged (3 dorsal, 2 ventral) with the 

polysiphonous branches laterally conjoined to form the flat uncorticated blade. The central axial cells of the polysiphonous 

branches form a pattern of fine veins that branch dichotomously 

within the flat thallus.

Tetrasporangia in flat marginal lobes of thallus, obliquely 

cruciately divided; in longitudinal series, 1 per segment. Gametophytes dioecious, reproductive structures radial in construction 

borne along margins of lobed thallus. Procarpial branchlets, usually 2 segments long with a single trichoblast; in short polysiphonous branchlets. Cystocarps spherical to ovoid. Spermatangial 

branchlets, forming a fringe along blade margins; spermatangia in conical stichidia borne on a monosiphonous stalk from a 

5-celled polysiphonous filament.

Remarks. The tribe placement of Amplisiphonia has 

been variously interpreted. In studying some dorsiventral Rhodomelaceae, Scagel (1953) considered Amplisiphonia and Placophora in the Herposiphonieae with affinities close to members of 

the Polysiphonieae and the Pterosiphonieae. On the basis of finding the reproductive structures in Amplisiphonia, Hollenberg and 
NUMBER 96 • 285

Wynne (1970) placed the genus in the tribe Polysiphonieae sensu 

Hommersand (1963). Kraft and Wynne (1985) later concluded 

that Amplisiphonia was closer to Pterosiphonia, and Womersley 

(2003) retained it in the Placophora group sensu Kylin (1956), 

close to but different than the genera of the tribe Pterosiphonieae.

A monotypic genus, its one known species is now reported 

in the northern Gulf of California.

Amplisiphonia? pacifica Hollenberg

FIGURE 139

Amplisiphonia pacifica Hollenberg, 1939:382, figs. 1–13; Smith, 1944:372, 

pl. 96: figs. 7–9; Scagel, 1953:39, fig. 5a–e; Scagel, 1957:239; Dawson et al., 1960a:44, pl. 43: fig. 2; 1960b:29; Dawson, 1961b:452; 

1963b:438, pl. 170: figs. 1, 2, pl. 171: figs. 5–7; Hollenberg and 

Wynne, 1970:175, figs. 1–5; Abbott and Hollenberg, 1976:720, 

fig. 670; Lindstrom and Scagel, 1980:400; Scagel et al., 1989:141; 

R. Aguilar-Rosas et al., 1990:120; Stewart, 1991:153; GonzálezGonzález et al., 1996:173.

Small, prostrate, dorsiventral blades, up to 6 mm long and 

to 2 mm wide; lobes often overlapping; growth from apical cells 

at blade margins; apical cells without trichoblasts, develop polysiphonous axes of 5 pericentral cells, dorsiventrally arranged (3 

dorsal, 2 ventral); axes laterally adjoining, branched dichotomously, central axial filament cells often form pattern of delicate 

veins within blade. Thallus uncorticated, attached by unicellular 

rhizoids from ventral surface.

Reproduction not found in Gulf material. As reported elsewhere: tetrasporangia obliquely, cruciately divided, developed in 

marginal lobes (Abbott and Hollenberg, 1976); cystocarps subspherical, 400–550 μm by 530–700 μm; spermatangial stichidia 

on a single cell off polysiphonous branchlets, up to 525 μm long, 

fringing along blade margins (Hollenberg and Wynne, 1970).

FIGURE 139. Amplisiphonia? pacifica: A. Habit of small blade. B. Margin of numerous apical cells that initiate polysiphonous axes that laterally unite behind the margin to form the flat blade. C. Dorsal surface view of blade with internal pattern of fine veins (axial filaments) (A–C, 

JN-4682, US Alg. Coll. microscope slide 4984).
286 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Habitat. Epiphytic on Palisada paniculata; low intertidal to shallow subtidal, down to at least 10 m depths.

Distribution. Gulf of California: Puerto Calamajue. Eastern Pacific: Aleutian Islands, Alaska to Islotes Chester 

(islets about 0.8 km [0.5 mile], NW of Punta Falsa), Bahía Sebastián Vizcaíno, Baja California Sur.

Type Locality. On rocky shore, lower intertidal; 

Corona Del Mar, Orange County, southern California, USA.

Remarks. Apparently rare in the Gulf, a few, small, 

nonreproductive specimens are tentatively referred to Amplisiphonia? pacifica (JN-4682, US Alg. Coll. microscope slide 4984). 

Epiphytic on Palisada paniculata from Puerto Calamajue, they 

represent a new record of the genus in the Gulf of California. 

The northern Gulf A.? pacifica differs from those of southern California in being partially prostrate with a free blade that 

is not as lobed, and the characteristic attaching rhizoids on the 

lower surface were not observed (cf. Smith, 1944: pl. 96: figs. 7, 

8; Abbott and Hollenberg, 1976: fig. 670). With these differences 

and lacking reproductive specimens, we cannot be sure of the generic placement of the Gulf material. Superficially, the northern 

Gulf Amplisiphonia? pacifica is also somewhat similar to blades 

of Pollexfenia? anacapensis E. Y. Dawson et Neushul (1966: cf. 

fig. 7; with taxonomic query on generic placement). However, 

according to Womersley (2003), the genus Pollexfenia Harvey 

(1844) is restricted to southern Australia. The Gulf material referred to A.? pacifica is dorsiventral and has five pericentral cells, 

whereas P.? anacapensis is not dorsiventral and has an unusual 

hollow internal structure traversed by a network of veins and the 

strut work of four pericentral cells (two dorsal and two ventral) 

attached to the cortical cells. Gulf A.? pacifica is also somewhat 

similar to another dorsiventral genus, Placophora J. Agardh 

(1863). More Gulf A.? pacifica is needed for molecular and morphological comparisons with type locality material of California 

A. pacifica and Pollexfenia? anacapensis and members of Placophora to resolve its taxonomic status. 

Rhodomelaceae tribus Brongniartelleae

Rhodomelaceae tribus Brongniartelleae M. Parsons, 1975:691.

Thalli radially branched, polysiphonous with uncorticated 

or corticated segments, of 4–7 pericentral cells; some genera with 

adventitious filaments develop from pericentral or cortical cells; 

branches with usually persistent pigmented trichoblasts, spirally 

arranged on successive segments. Gametophtyes dioecious; procarps at base of trichoblasts, 4-celled carpogonial branch with 

2 sterile cell groups; spermatangial structures borne on branch 

of trichoblasts. Tetrasporangia1–2 in linear rows or spirally arranged, usually with 3 cover cells (2 presporangial and in most 

genera 1 postsporangial), in normal polysiphonous axes. 

Remarks. Dawson (1944a) suggested the genus 

Veleroa was close to Lophocladia F. Schmitz (1893). Later, Parsons 

(1975), in describing the tribe Brongniartelleae, included Veleroa

along with some members of the Lophothalia group sensu Kylin 

(1956:510). Millar (2000) noted that the two tribes were separated 

by the number of sterile groups associated with procarps, and 

treated Veleroa as a member of tribe Brongniartelleae. Womersley 

and Parsons (2003) included it in a more broadly defined tribe 

Lophothalieae F. Schmitz et Falkenberg (1897). Millar (2000) and, 

more recently, Abbott and Ballantine (2012) in their studies of 

Veleroa supported its placement in tribe Brongniartelleae.

The tribe is represented by one genus in the northern Gulf 

of California.

Veleroa E. Y. Dawson 

Veleroa E. Y. Dawson, 1944a:335.

Algae composed of both erect and prostrate polysiphonous 

axes of uncorticated to corticated segments of 4 pericentral cells. 

Some species are either predominately prostrate, others predominately erect. Main axes are usually much branched, up to 

4(–5) orders, and bear persistent, irregularly radially arranged, 

monosiphonous, pigmented trichoblasts. Trichoblasts are simple 

or branched up to 4 times, spirally arranged, and more or less 

curved upward. Lateral branches develop at the base of trichoblasts. Prostrate polysiphonous axes produce holdfasts of uniseriate or multiseriate rhizoids with a terminal discoid pad. 

Tetrasporangia, each with 3 cover cells, are in spiral series, 1 

per segment within either slightly swollen upper portions of axes 

or in short indeterminate branches. Each segment of the tetrasporangial branch bears simple or rarely branched monosiphonous trichoblasts. Gametophytes, where known, are dioecious 

(not yet known from northern Gulf of California type locality). 

Procarps, where reported, have a 4-celled carpogonial branch 

with the carpogonium bearing a short trichogyne, developed on 

the suprabasal cell of trichoblasts. Cystocarps are more or less 

ovoid with a pericarp 2 cells thick and a prominent neck. Spermatangia are produced on intercalary cells of the trichoblasts; 

they may either cover the cells of the trichoblast filaments, have 

sterile cells that extend distally, or a sterile basal cell and no sterile distall cells (gametophyte descriptions after Womersley and 

Parsons, 2003; Abbott and Ballantine, 2012).

Remarks. Cystocarps and spermatangia have yet to 

be found in the northern Gulf generitype Veleroa subulata. Finding them from the Gulf type locality and the elucidation of procarpic and cystocarpic development are particularly important 

so they can be morphologically and molecularly compared to 

test their relationship with other members of the genus. 

Veleroa is currently a genus of seven species, with one species known in the Gulf of California.

Veleroa subulata E. Y. Dawson

FIGURE 140

Veleroa subulata E. Y. Dawson, 1944a:335, pl. 72: fig. 2 [type specimen]; 

1961b:451; 1963a:414, pl. 133; Abbott and Hollenberg, 1976:702, 

fig. 654; Anaya-Reyna and Riosmena-Rodríguez, 1996:864, tbl. 1; 

González-González et al., 1996:272; R. Aguilar-Rosas et al., 1997:19, 

fig. 2; 2000:132; Riosmena-Rodríguez et al., 2005a:34; Abbott and 

Ballantine, 2012:388, fig. 1A–H.
NUMBER 96 • 287

Algae up to 15 mm tall with erect main axes and branches 

consisting of 4 uncorticated pericentral cells per polysiphonous 

segment, mostly 50–70 μm in diameter, 100–140 μm long; arising from protrate axes, up to 100 μm in diameter, attached to 

substratum by multicellular rhizoids with terminal pads, 250–500 

μm in diameter. Pericentral cells connected lengthwise by secondary pit connections. Erect axis, usually sparingly branched with 

indeterminate branches, 50–70 μm in diameter, irregularly radially 

arranged at intervals of up to 16 cell segments between branches. 

Axes and branches with exogenous, persistent, pigmented monosiphonous trichoblasts, typically one per segment. Trichoblasts 

arranged in a spiral sequence, usually simple or occasionally 

branched, mostly 400–800 μm long and 25–40 μm in diameter; 

slightly curved upward and often tapering to a acute terminal cell.

Tetrasporangia tetrahedrally divided, 37–50 μm in diameter, 

42–60 μm in length; intercalary, 1 per segment in spiral series of 

8–15(–34) within slightly swollen segments of upper portions of 

indeterminate main axes and branches. Gametophytes unknown 

in the Gulf of California, presumed to be dioecious. As described 

from Pacific northern Baja California and southern California: 

procarps on the second segment of a trichoblast (Stewart, 1989, 

included Murrayellopsis); cystocarps unknown; spermatangia 

develop from intercalary cells, encircling trichoblast filaments 

forming subcylindrical clusters up to 130 μm in length, 30–70 

μm in diameter between 1–3 basal sterile cells and 6–8 sterile 

terminal cells (after Aguilar-Rosas et al., 1997; Abbott and Ballantine, 2012).

Habitat. On rocks or hydroids; shallow subtidal, 

3.0–15 m depths (also dredged from 22 m depth).

Distribution. Gulf of California: El Coloradito; 

Bahía Tepoca; Punta Los Frailes to Cabo Pulmo.

Type Locality. Epizoic on a small hydroid, dredged 

from 22 m depth; Bahía Tepoca, Sonora, Gulf of California, 

Mexico.

Remarks. Once gametangial thalli of Veleroa subulata are found from its type locality, comparison to the other 

known species is needed to resolve their phylogenetic relationships. The taxonomic status of Murrayellopsis E. Post (1962; 

type locality: New Hope Rock, off Point Loma, San Diego 

County) is problematic, and its relationship to Veleroa requires 

further investigation.

Millar (1999) suggested another species, the Hawaiian Micropeuce setosus I. A. Abbott (1996), may also be Veleroa subulata. Stewart (1989, 1991) concluded the southern California 

FIGURE 140. Veleroa subulata: Polysiphonous main axes with tetrasporangia in spiral series, one per segment, and monosiphonous laterals (drawn from holotype: EYD-381d-40, AHFH-63, now UC).
288 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Murrayellopsis was congeneric with Veleroa, thus making M. 

dawsonii E. Post (1962) a synonym of V. subulata. Others however, recognize Murrayellopsis (Dawson, 1963a; Post, 1963, 

1964; Abbott and Hollenberg, 1976; Millar, 2000) on the basis 

of its polysiphonous segments of 5 pericentral cells and 2 tetrasporangia per segment, differing from Veleroa with strictly 

4 pericentral cells per segment and 1 tetrasporangia per segment. Murrayellopsis dawsonii is reported in the Eastern Pacific from central California to northern Baja California, Pacific 

Mexico (Abbott and Hollenberg, 1976), from Islas Todos Santos (off Ensenada), northern Baja California (R. Aguilar-Rosas 

et al., 1990; González-González et al., 1996), and from Jalisco 

(Hernández-Herrera et al., 2005). In the California Channel Islands, M. dawsonii, Tiffaniella snyderae, and Pterosiphonia dendroidea are the predominant components of the cultivated nests 

of living algae maintained by a pomacentrid fish, the garibaldi, 

Hypsypops rubicundus (Dawson, 1963a; Foster, 1972, both as 

“Murrayellopsis dawsonii”; Foster and Scheil, 1985). 

Spyridiaceae

Spyridiaceae J. Agardh, 1851:vii, 337 [as “Spyridieae”].

Thalli are erect, uniaxial in structure, radially branched, and 

differentiated into nearly completely corticated indeterminate 

axes and determinate branchlets that are corticated only at the 

nodes. Determinate branchlets develop from the primary axes 

and indeterminate lateral branches, and are simple or sparsely 

branched and monosiphonous, with a narrow band of small corticating cells at the distal end of their axial cells (i.e., nodes); the 

internodes remain uncorticated. Cells are multinucleate. Gland 

cells are absent.

Tetrasporangia are tetrahedrally divided, sessile and naked 

on the cortical bands of determinate branchlets. Gametophytes 

are dioecious. The carpogonial branch is 4-celled and borne on a 

periaxial cell of the fully corticated axes. Carposporophyte surrounded by pericarpic filaments from segments above and below 

the fertile axial cell. Spermatangia originating on the corticated 

nodes of determinate branchlets, later forming a confluent cylinder around several successive cells of fertile segments on lower 

portions of determinate branchlets. 

The family contains the single genus Spyridia, which occurs 

in the northern Gulf of California.

Spyridia Harvey 

Spyridia Harvey, 1833:259, 336.

Thallus erect, most species richly radially branched, giving axes a fuzzy appearance; branches distichous or irregularly 

arranged; indeterminate branches with unbranched or sparsely 

branched determinate branchlets. Axes terete, composed of large 

axial cells completely corticated by tiers of cells and in older portions of the thallus additionally corticated by descending rhizoidlike filaments. Axial filament cells of indeterminate branches cut 

off a ring of periaxial cells around the node between 2 axial cells. 

Each periaxial cell of the encircling ring cuts off 2 basipetal cells 

from its proximal (lower) end, and these basipetal cells elongate 

and become pit connected to the periaxial cells of the node or 

segment below to completely cover the axial filament cells. This 

repeated pattern builds a cortex of short, relatively broad nodal 

cells alternating with a band of twice as many longer narrower 

cells (basipetal cells) that lengthen as the axial filament cells grow 

and enlarge. Determinate branchlets simple or sparsely branched 

and radially arranged; spiraled or in whorls. Determinate branchlets consisting of uniseriate axes of larger translucent axial cells 

that are corticated by a band of smaller cells at all or nearly all 

(depending on species) their nodes, internodes uncorticated; with 

or without short apical spines or hooks, these often shed early. 

Cells multinucleate. 

Tetrasporangia tetrahedrally divided, naked and sessile at 

the nodes of determinate branchlets. Tetrasporangial production 

begins on adaxial side, and as more tetrasporangia are issued, 

they appear whorled about the cortical bands. Gametophytes dioecious. Procarps are borne on the periaxial cells that corticate 

a indeterminate branch, carpogonial branch 4-celled. Cystocarps 

are borne near ends of a short, indeterminate branch (apparently 

restricted in growth); often bilobed and surrounded by slender 

pericarpic filaments developed from segments above and below 

the fertile axial cell. Spermatangial parent cells are produced by 

the nodal band of cortical cells of determinate branchlets, and 

the spermatangia form a continuous colorless surface layer over 

several segments (node and internode) in lower portions of determinate branchlets.

Remarks. Agardh (1897) wrote that there were 

many opinions concerning the true affinity of Spyridia. Schmitz 

(1889) placed the genus in the Ceramiaceae, and this has been 

generally followed, but Phillips (1924) thought it was closer to 

the Wrangeliaceae and should be given an ordinal position. Since 

then, phylogenetic data supported Spyridia belonging in the family Spyridiaceae (H.-G. Choi et al., 2008). However the species 

are problematic and still in need of elucidation (e.g., Zuccarello 

et al., 2002a, 2004b). Studies by Feldmann and FeldmannMazoyer (1943) and West and Calumpong (1989) have shown 

Spyridia to have a triphasic life history. 

One species of uncertain identity occurs in the northern 

Gulf of California. 

Spyridia cf. filamentosa

FIGURE 141

Spyridia filamentosa sensu McClatchie, 1897:357; Setchell and Gardner, 

1930:167; Dawson, 1962a:69, pl. 30: figs. 1–3; Abbott and Hollenberg, 1976:608, fig. 551; Huerta-Múzquiz, 1978:336; L. AguilarRosas, 1982:84; Pacheco-Ruíz and Aguilar-Rosas, 1984:73; Stewart 

and Stewart, 1984:145; Huerta-Múzquiz and Mendoza-González, 

1985:52; Ibarra-Obando and Aguilar-Rosas, 1985:95, 102; MendozaGonzález and Mateo-Cid, 1986:425; Ortega et al., 1987:74; SánchezRodríguez et al., 1989:44; Stewart, 1991:136; Serviere-Zaragoza et 

al., 1993a:484; Mateo-Cid et al., 1993:48; González-González et al., 

1996:325, 413; Anaya-Reyna and Riosmena-Rodríguez, 1996:864, tbl. 
NUMBER 96 • 289

FIGURE 141. Spyridia cf. filamentosa: A, B. Portions of two thalli to show habit variations (A, JN-3140, US Alg. Coll.-160963; B, JN-4060, 

US Alg. Coll.-160981). C. Cortical pattern of completely corticated indeterminate axis and determinate branchlets corticated only at nodes. D, 

E. Apices of determinate branchlets, each with a single, terminal spine. F. Apical region of main axis with radially arranged indeterminate and 

determinate branches (C, D, JN-4075, US Alg. Coll. microscope slide 4836; E, F, JN-4019, US Alg. Coll. microscope slide 4834).
290 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

1; Riosmena-Rodríguez et al., 1998:26; Cruz-Ayala et al., 1998:191; 

Mateo-Cid et al., 2000:66; L. Aguilar-Rosas et al., 2000:131; 

CONANP, 2002:138; Cruz-Ayala et al., 2001:191; L. Aguilar-Rosas 

et al., 2002:235; Pacheco-Ruíz and Zertuche-González, 2002:468; 

Mateo-Cid et al., 2006:57; Serviere-Zaragoza et al., 2007:12; PachecoRuíz et al., 2008:211; Piñón-Gimate et al., 2008:116; Bernecker, 

2009:CD-Rom p. 65; Fernández-García et al., 2011:64; Pérez-Estrada 

et al., 2012:191 [non Spyridia filamentosa (Wulfen) Harvey, 1833:337; 

basionym: Fucus filamentosus Wulfen, 1803:64].

Algae soft and bushy, to 20 cm long, lax, pink to grayish 

rose in color, epiphytic, saxicolous, or free floating in entangled 

masses. Axes terete, with 1 to several main axes, 1–2 mm in diameter, main axes of large uniseriate cells completely corticated, 

except near the apices. Axial filament cells producing a ring of 

periaxial cells that surrounds the node between adjacent axial 

cells. Each periaxial cell issues (1–)2 basipetal cells from below 

that elongate to cover the axial cell as it grows and lengthens. 

In the upper portions of the axes, the cortex in surface view is 

composed of alternating tiers of 14–18 short, wide cells (periaxial cells) and then a tier of about twice that number of elongate thinner cells (basipetal cells); the regular cortical pattern 

is visible in upper portions, but in older portions below, this 

pattern becomes obscured by the growth of descending rhizoidal corticating cells that cover and thicken the original cortex 

to 2–3 cell layers deep. Indeterminate axes with numerous, 

slender, unbranched, irregularly spirally arranged, determinate 

branchlets (35–60 μm in diameter, to about 1.5 mm in length, 

and about 15–25 cells long). Determinate branchlets cylindrical, 

not tapering toward the base, composed of axial cells, cortication confined to distinct bands at their nodes (similar to some 

Ceramium species); arising from enlarged periaxial cells of the 

indeterminate branch cortex, typically 1 determinate branchlet 

per segment. Each axial cell of a determinate branchlet issues 

about 9 periaxial cells at its distal end that divide to form 1–3 

cell tiers of small pigmented cells that constitute the corticating 

band. Uncorticated internode length reduced toward branchlet 

tip; determinate branchlets usually terminating in a single short 

1- to 2-celled spine.

Tetrasporangia sessile, spherical, 45–80 μm in diameter, including large clear envelope, tetrahedrally divided; 1 to several 

tetrasporangia whorled about nodes of determinate branchlets, 

particularly on the proximal cells (but not the basal cell). Carpogonia and spermatangia not reported for Gulf material (for 

descriptions, see Womersley, 1998; H.-G. Choi et al., 2008).

Habitat. Epiphytic on or entangled with other algae 

or aquatic vegetation, including mangroves, on rocks or tidal 

platforms or in coastal lagoons, or free floating in often large, 

entangled masses; intertidal.

Distribution. Gulf of California: El Tornillal (Gulfo 

de Santa Clara) to Punta Los Frailes; Laguna Agiabampo; Bahía de 

Navachiste to Teacapán; Bahía de Banderas, Sinaloa to Nayarit. 

Eastern Pacific: La Jolla, southern California to Bahía Magdalena, 

Baja California Sur; Isla Guadalupe; Isla Clarión (Islas Revillagigedo); El Salvador; Nicaragua; Costa Rica; Panama.

Type Locality. Vienna? (Maggs and Hommersand, 

1993:427); Adriatic Sea (Silva et al., 1996a:136).

Remarks. Spyridia cf. filamentosa is apparently a recent invader into the upper Gulf of California. First recorded in 

the drift at Punta Los Frailes, near the Gulf’s southern entrance 

(Dawson, 1962a:69), the species had not been noted in earlier 

algal studies of the northern Gulf (e.g., Setchell and Gardner, 

1924; Dawson, 1944a, 1962a; Norris, 1973). Collections beginning in 1972 revealed Spyridia at several northern Gulf locales 

(Norris, 1975), where, seasonally, it sometimes formed sizable 

floating rafts and was abundant in beach drift. Although the phycology courses from the University of Arizona (1964–1972) included collecting field trips to Puerto Peñasco in the upper Gulf, 

Robert Hoshaw (University of Arizona, personal communication, 

1972) noted S. filamentosa was never observed or collected during that time, nor was it included by Dawson (1966a). During 

our year-round work at Puerto Peñasco (Laboratorio de Biología 

Marina, 1972–1975) we would seasonally observe floating rafts 

of Spyridia, sometimes entangled with other drift algae, some of 

which eventually would be cast ashore. These were conspicuous, 

particularly in summer, suggesting if the species had been there 

prior to 1972 it probably would have been observed.

Seasonal biomass studies in Bahía La Paz of Cruz-Ayala et 

al. (1998) found southern Gulf “S. filamentosa” to be one of the 

most abundant macroalga during summer (second only to Sargassum sinicola) and also in winter. Observations of L. AguilarRosas et al. (2002) indicated “S. filamentosa” was one of the 

most common species in the upper Gulf at their study sites in 

Gulfo de Santa Clara, Sonora.

Molecular data and morphological and culture studies of 

“S. filamentosa” as identified from specimens throughout the 

world’s oceans showed a complex phylogeographic pattern and 

distinct evolutionary lineages that led Zuccarello et al. (2002a, 

2004b) to conclude that there are several cryptic species identified under the name “S. filamentosa.” One of the “cryptic” species with disparate DNA sequences was recognized from Europe, 

S. griffithsiana (J. E. Smith) Zuccarello, Prud’homme van Reine 

et Stegenga (2004b; basionym: Conferva griffithsiana J. E. Smith, 

1812). Morphologically, this species can be distinguished by determinate branchlets that strongly taper toward their base, and 

the proximal two (or one) segments have a small axial cell that is 

without a cortical ring. The determinate branchlets of northern 

Gulf of California S. cf. filamentosa are cylindrical, not tapering strongly toward their base, and all segments of determinate 

branchlets have a cortical ring at the nodes.

Zuccarello et al. (2002a, 2004b) found two sister clades in 

the Pacific S. filamentosa lineage, one of which was an anomalous group that although morphologically similar, may be a 

separate species. Molecular and morphological analyses of “S. 

filamentosa” in Hawaii revealed five clades that grouped in two 

lineages (Conklin and Sherwood, 2012: fig. 1). A southern Gulf 

of California “S. filamentosa” from Mulege, Baja California Sur, 

was included in their Lineage I. Comparative testing needs to be 

conducted on northern Gulf “S. cf. filamentosa” to determine 
NUMBER 96 • 291

if they can be identified with one of these lineages or if they are 

possibly different. Until these studies are completed, the northern 

Gulf specimens are tentatively referred to “S. cf. filamentosa.” 

Wrangeliaceae

Wrangeliaceae J. Agardh, 1851:x, 701 [as “Wrangelieae”]. 

Thalli usually erect or with erect and prostrate axes, uniseriate filaments. Axial cells with none to 6 determinate branches or 

whorl branches. Gland cells usually absent. 

Meiosporangia tetrahedrally divided or with polysporangia, 

sessile or stalked on cells of the whorl branches or determinate 

branches. Gametophytes usually dioecious. Procarps subapical, 

carpogonial branches 4-celled. The supporting cell is a subapical 

cell of a short fertile axis with 2 or 3 periaxial cells. Procarps 

formed from a periaxial cell of a fertile axial cell with or without 1 sterile cell group on the supporting cell. A multicellular 

fusion cell is present in the carposporophyte of most tribes. Carposporophytes naked or involucrate or, in one genus(Lejolisia), 

surrounded by a “pericarp-like” structure. Spermatangia are sessile or pedicellate in clusters of cap or subspherical to elongate 

“head-like” structures, terminal on short lateral branches, or in 

whorls from the distal end of axial cells or from basal cell of a 

trichoblast. 

The Wrangeliaceae is represented by five genera in the 

northern Gulf of California.

KEY TO THE GENERA OF THE WRANGELIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. In upper portions of thallus nearly every axial cell with a lateral branch; main axes alternately branched . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pleonosporium

1b. In upper portions not every axial cell with a lateral branch; branching not as above . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Thallus cells uninucleate; carposporophyte surrounded by a loose “pericarp-like” structure of 1 layer of cells within a 

common gelatinous sheath . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lejolisia

2b. Thallus cells multinucleate; cystocarp naked or may be surrounded by involucres but not a “pericarp-like” structure . . . 3

3a. Carposporophyte naked, lacks surrounding involucres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tiffaniella

3b. Carposporophyte surrounded by involucres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Tetrasporangia borne singly on a pedicel without involucres, solitary or in whorls; spermatangia clustered in a single “head,” 

each borne on 1-celled pedicel or on basal cell of a trichoblast, several “heads” borne in a whorl . . . . . . . . . Anotrichium

4b. Tetrasporangia borne 2 or more to a fascicle, usually with involucres; spermatangia on branched fascicles that are borne 

between axial cells or cap-like on terminal cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Griffithsia

Wrangeliaceae tribus Griffithsieae

Wrangeliaceae tribus Griffithsieae F. Schmitz, 1889:449.

The tribe Griffithsieae is represented by two genera in the 

northern Gulf of California.

Anotrichium Nägeli 

Anotrichium Nägeli, 1862:397. 

Algae are uniseriate filaments that may be erect or with 

prostrate and erect portions, attached by elongate unicellular 

rhizoids issued from cells in basal or prostrate regions. Branching may be subdi(tri)chotomous, subsecund, to irregular. Most 

species are ecorticate, or some species corticated basally by descending rhizoids. Axial cells are cylindrical, usually elongate, 

and multinucleate. Whorls of di- to polychotomous unpigmented 

trichoblasts are produced from the distal ends of cells near the 

apices. The slender trichoblasts are typically shed early or may 

not always develop, although trichoblasts are frequently found 

persisting on reproductive plants.

Tetrasporangia are borne in upper portions of the thallus 

and are divided tetrahedrally, without involucral filaments. Each 

tetrasporangia is single and terminal or subterminal “adaxial” 

on a pedicel, pedicels borne solitary or in whorls of 2 or more 

from the distal ends of axial cells; or tetrasporangia borne adaxial from the basal cell of a trichoblast. Gametophytes dioecious. Cystocarps terminating branchlets, the hypogenous cell 

bearing a whorl of postfertilization involucral branches, usually 

single cells that elongate around the gonimoblasts. Spermatangia 

clustered, forming spherical to oblong “heads,” each head on a 

clavate pedicel, which is solitary or in whorls from the distal end 

of axial cells; or borne adaxial from the basal cell of a trichoblast in the whorl. Spermatangial heads not involucrate (after 

Baldock, 1976.)

Four species of Anotrichium are reported to occur in the 

northern Gulf of California. 

KEY TO THE SPECIES OF ANOTRICHIUM AND GRIFFITHSIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli often decumbent; branching subsecund to irregular, most branching adventitious; adventitious branches issued 

from proximal end of axial cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Anotrichium secundum

1b. Thalli more or less erect; dichotomously to subdichotomously branched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Ultimate cells 5.0–30 μm in diameter; tetrasporangia without involucres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2b. Ultimate cells larger, mostly 70–125 μm in diameter; tetrasporangia with or without involucres . . . . . . . . . . . . . . . . . 4
292 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

3a. Filaments with apical cells 14–20 μm in diameter; mid to upper cells 170–250 μm in diameter, 600–1200 μm (or more) 

long; lower cells up to 2000 μm long, 300–500 μm in diameter with thick cell walls (up to 28 μm) . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Anotrichium furcellatum

3b. Filaments with larger apical cells, 15–30 μm in diameter; mid to upper cells narrower in diameter, about 125 μm, up to 

970 μm long; lower cells up to 1350 μm long by 300 μm in diameter . . . . . . . . . . . . . . . . Anotrichium multiramosum

4a. Thalli 3–5 cm tall, 300–500 μm in diameter in middle to lower portions; tetrasporangia borne 2 or more to a fascicle, 

usually with involucres, borne on richly branched fascicles between the upper axial cells or as a cap terminating lateral 

branches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Griffithsia pacifica

4b. Thalli shorter, 1–2 cm high, and narrower; 150–280 μm diameter in middle portions; tetrasporangia borne singly on 

1(–2)-celled pedicels, without involucres . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Anotrichium anthericephalum

Anotrichium anthericephalum (E. Y. Dawson) Baldock

Griffithsia anthericephala E. Y. Dawson, 1950b:155, figs. 20, 21; 1961b:444; 

1962a:70, pl. 28; Stewart and Stewart, 1984:146; González-González 

et al., 1996:219. 

Anotrichium anthericephalum (E. Y. Dawson) Baldock, 1976:560.

Thalli to 2 cm high, uniseriate, composed of dichotomously 

branched filaments, occasionally trichotomous in uppermost 

portion. Middle portions of thallus with axial cells 150–280 μm 

in diameter, 4–6 diameters long, increasing in diameter toward 

the distal end of a cell, appearing somewhat clavate. Apical cells 

oblong, blunt; subapical cells without whorls of trichoblasts.

Tetrasporangia up to 75 μm in diameter, naked, borne on 

1-celled pedicels, 2 to several tetrasporangial branches whorled 

about distal end of upper axial cells. Cystocarps borne on 

1-celled lateral branches, with a prominent involucre of incurved 

1-celled filaments. Spermatangia forming dense, ovoid cluster, 

borne on 1-celled pedicels at the distal end of upper axial cells.

Habitat. Epiphytic on various algae; intertidal to 

shallow subtidal, down to 20 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to El Desemboque. Eastern Pacific: Isla Guadalupe (off Baja 

California); Punta Eugenia (“San Eugenio”), Baja California Sur.

Type Locality. Intertidal; north side of reef, on 

southwest tip of Isla Guadalupe, Baja California, Pacific Mexico.

Anotrichium furcellatum (J. Agardh) Baldock

FIGURE 142

Griffithsia furcellata J. Agardh, 1842:75; L’Hardy Halos, 1968a:523; Abbott 

and Hollenberg, 1976:621, fig. 563; Stewart and Stewart, 1984:146; 

R. Aguilar-Rosas et al., 1985:84; Ibarra-Obando and Aguilar-Rosas, 

1985:96; Sánchez-Rodríguez et al., 1989:45; Stewart, 1991:132; 

González-González et al., 1996:219; Pacheco-Ruíz and ZertucheGonzález, 2002:468; Riosmena-Rodríguez et al., 2005a:33. 

Anotrichium furcellatum (J. Agardh) Baldock, 1976:560; Maggs and Hommersand, 1993:181, fig. 59A–C; Pacheco-Ruíz et al., 2008:211. 

Neomonospora furcellata (J. Agardh) Feldmann-Mazoyer et Meslin, 

1939:193, figs. 1, 2.

Filamentous tufts, up to 6 cm tall, rose pink in color, and 

subdichotomously branched in 1 plane, occasionally in upper 

portions irregularly branched; upper portions much branched, 

corymbose; attached to substratum by numerous, entangled 

rhizoids. Axial cells cylindrical to slightly clavate, in middle to 

upper portions exceedingly elongate, mostly 600–1200 μm long, 

170–250 μm in diameter; in lower portions, up to 2000 μm long, 

300–500 μm in diameter, with cell walls 20–28 μm thick. One or 

more rhizoidal filaments, developed from axial cells, may wrap 

around or fuse to adjoining filaments. Ultimate cells tapered toward apex, 14–20 μm in diameter, with blunt apices. Trichoblasts absent (at least in sterile and tetrasporangial thalli).

Tetrasporangia pyriform to spherical, without involucre, 

45–60 μm in diameter, with thick outer wall (about 8 μm thick); 

borne singly on short, 1-celled pedicels at branch forks near distal 

ends of cell. Sexual reproduction for Gulf specimens: procarpic 

thalli with numerous trichoblasts; procarp with 1 carpogonial 

branch and 1 sterile cell on fertile pericentral. Spermatangia 

forming dense oval “heads,” borne on 1-celled pedicels.

Habitat. Usually epiphytic on other algae, in sheltered bays, lagoons, and calm subtidal habitats; dredged to approximately 40 m depths.

Distribution. Gulf of California: Puerto Peñasco to 

Punta Gorda; San José del Cabo. Eastern Pacific: Newport Bay to 

San Diego, southern California; Isla Guadalupe; Bahía Todos Santos and Estero Punta Banda to Bahía San Quintín, Baja California; 

Bahía de Ballenas to Bahía Magdalena, Baja California Sur. 

Type Locality. Near Amalfi, Sorrentine Peninsula, 

province of Naples, Tyrrhenian Sea, Italy. 

Remarks. Gulf of California specimens that are referred to Anotrichium furcellatum are similar to those of Gulf 

A. multiramosum. The two are separated in the Gulf primarily 

on cell sizes of the filaments and the corymbose nature of the 

upper thallus of A. furcellatum. Additional material needs to be 

critically studied and the molecular and morphological data used 

to evaluate the taxonomic status of these species as known in the 

Gulf of California.

Anotrichium multiramosum (Setchell et N. L. Gardner) 

Baldock

Neomonospora multiramosa Setchell et N. L. Gardner, 1937:87, pl. 4: fig. 

10a–c; González-González et al., 1996:245. 

Anotrichium multiramosum (Setchell et N. L. Gardner) Baldock, 1976:560. 

Griffithsia multiramosa (Setchell et N. L. Gardner) W. R. Taylor, 1939:14; 

Dawson, 1944a:315; 1945b:58; 1951:54; 1961b:444; 1962a:71, 

pl. 32; Stewart and Stewart, 1984:146; González-González et al., 

1996:220; Pacheco-Ruíz et al., 2008:211.

Griffithsia multiramosa var. balboensis Hollenberg, 1945:447, fig. 1; Dawson, 1961b:444. 
NUMBER 96 • 293

Griffithsia multiramosa var. minor W. R. Taylor, 1939:14, pl. 2; Dawson, 

1961b:444; González-González et al., 1996:220. 

Anotrichium multiramosum var. minor (W. R. Taylor) Baldock, 1976:560.

Algae in tufts, mostly 2–4 cm tall; filaments usually pseudodichotomously to alternately branched (occasionally slightly 

irregular in upper portions), ultimate branching dichotomous. 

Filament cells in lower portion of thallus, thick walled, up to 

1,350 μm long, up to 300 μm in diameter, branched at wide 

angles; in middle to upper portions cells slender, up to 970 μm 

long, mostly subcylindrical, about 125 μm in diameter; ultimate 

branchlet cells 100–200 μm long, 15–30 μm in diameter, with tapered apical cells with acute to rounded tips. Trichoblasts absent.

Tetrasporangia spherical, 50–75 μm in diameter; borne single on a 1-celled pedicel at branch nodes in upper and middle 

portions of thallus; without involucre cells. Carpogonial and 

spermatangial thalli not known.

Habitat. On rocks; intertidal to subtidal, down to 

12 m depths (also dredged from 20–50 depths). 

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda to Ensenada San Francisco; Punta Gorda 

(Gulfo de Santa Clara) to San José del Cabo. Eastern Pacific: 

Bahía San Quintín to Punta María (Baja California); Isla Guadalupe; Isla Cedros; Laguna de Ojo de Liebre (Scammon’s Lagoon) 

to Bahía Magdalena (Baja California Sur). 

Type Locality. San José del Cabo, Baja California 

Sur, Gulf of California, Mexico.

Remarks. Anotrichium multiramosum is morphologically similar to A. furcellatum. Although it has been suggested 

the two are conspecific (L’Hardy-Halos, 1968a; Abbott and 

Hollenberg, 1976), they are kept separate in this treatment. The 

relationship of A. multiramosum, a species described from the 

southernmost Gulf of California, to Gulf material referred to A. 

furcellatum and to the Mediterranean A. furcellatum (type locality: Amalfi, Italy) remains to be genetically tested and elucidated.

Anotrichium secundum (Harvey ex J. Agardh) G. Furnari

FIGURE 143

Griffithsia secunda Harvey ex J. Agardh, 1851:85. 

Anotrichium secundum (Harvey ex J. Agardh) G. Furnari in Cormaci, Furnari et Pizzuto, 1994:635; Abbott, 1999:245, fig. 68A–C.

Anotrichium tenue var. secundatum (Harvey ex J. Agardh) Stegenga, 

1985a:154, nom. invalid.

Anotrichium tenue var. secundatum (Harvey ex J. Agardh) Stegenga ex H.-S. 

Kim et I. K. Lee, 1991:19.

FIGURE 142. Anotrichium furcellatum: A. Upper portion of thallus 

showing subdichotomous branching, elongate axial cells, and tetrasporangia (arrows) usually borne solitary at nodes. B. Tetrasporangium borne on single-celled pedicel (A, B, JN-4487, US Alg. Coll. 

microscope slide 4969).
294 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Callithamnion thyrsigerum Thwaites ex Harvey, 1855:559.

Griffithsia thyrsigerum (Thwaites ex Harvey) Grunow, 1874:30.

Anotrichium tenue var. thyrsigerum (Thwaites ex Harvey) H.-S. Kim et 

I. K. Lee in I. K. Lee, 1992:159 [Anotrichium tenue var. thyrsigerum

(Thwaites ex Harvey) H.-S. Kim et I. K. Lee, 1991:19, comb. invalid.].

Griffithsia tenuis sensu Dawson, 1944a:315; 1959a:32; 1961b:444; 

1962a:73, pl. 31: figs. 5–7; 1966a:28; Huerta-Múzquiz and TiradoLizárraga, 1970:129; Chávez-Barrear, 1972b:269; Baldock, 1976:556, 

figs. 59–64, 90; González-González et al., 1996:316 [in part]; 

CONANP, 2002:138; Pacheco-Ruíz and Zertuche-González, 2002:468 

[non Griffithsia tenuis C. Agardh, 1828:131, which is now Anotrichium tenue (C. Agardh) Nägeli, 1862:399]. 

Anotrichium tenue sensu Mateo-Cid et al., 1993:48; Mendoza-González 

et al., 1994:108;Mateo-Cid et al., 2000:66; L. Aguilar-Rosas et al., 

2000:131; Pacheco-Ruíz and Zertuche-González, 2002:468; MateoCid et al., 2006:56; Serviere-Zaragoza et al., 2007:9; Pacheco-Ruíz et 

al., 2008:211 [non Anotrichium tenue (C. Agardh) Nägeli, 1862:399, 

415; see Cormaci et al., 1994:635].

Thalli forming loose mat of filaments, up to 5 cm high in the 

Gulf, decumbent with erect axes, branching subsecund to irregular, much of the branching adventitious; adventitious branches 

developing from proximal ends of axial filament cells; rarely, when 

subdichotomous, branches developing from a subapical cell after 

it cuts off an apical lobe. Axial cells cylindrical, elongate, in basal 

portions up to 300 μm in diameter and up to 1200 μm long, decreasing in dimensions in upper portions. Apical cells 35–70 μm in 

diameter, 30–45 μm long, and several subapical cells below short 

subcylindrical, the cell just below the apical cell the shortest (10–

35 μm long), subapical cells each often producing a whorl of protrusions at their distal end that elongate and develop into slender, 

unpigmented trichoblasts. Trichoblasts to about 150 μm long, and 

di- to polychotomously branched to 2 orders. The dense whorls of 

apical trichoblasts (8–16 in a ring) are often soon shed. Thallus attached by elongate unicellular rhizoids issued from prostrate axes, 

rhizoids sometimes terminate in elaborate digitate discs.

Tetrasporangia spherical, tetrahedrally divided, 60–80 

μm in diameter; single, somewhat subterminal and adaxial on 

1-celled pedicel, in a whorl of 8–10(–12) on the distal end of 

axial cells near thallus apices. Carposporangia and spermatangia 

not observed in Gulf material. 

Habitat. On rocks, in crevices, and in tide pools or 

epiphytic on other algae; intertidal to shallow subtidal.

FIGURE 143. Anotrichium secundum: A. Portion of thallus showing subsecund, adventitious branching from proximal ends of axial cells (JN5187, US Alg. Coll. microscope slide 4952). B. Subapical cells bearing polychotomously branched trichoblasts that are later shed (JN-4032, US 

Alg. Coll. microscope slide 4961).
NUMBER 96 • 295

Distribution. Gulf of California: Puerto Peñasco 

to Puerto Escondido; Punta Arena to Cabo Pulmo; Mazatlán. 

Eastern Pacific: Isla Guadalupe (off Baja California); Isla Socorro 

and Isla Clarión (Islas Revillagigedo); Guerrero to Oaxaca. Central Pacific: Hawaiian Islands. Western Pacific: Korea.

Type Locality. “Ad oras Capenses” (J. Agardh, 

1851:85); Muizenberg, False Bay, Cape Province, South Africa 

(Silva et al., 1996a:376).

Remarks. Cormaci et al. (1994) helped clarify a confused taxonomy and nomenclature, involving misidentifications and 

misapplication of names of some taxa of Anotrichium. On the basis 

of recent interpretations, the northern Gulf material is identified 

as Anotrichium secundum. Changes in taxonomy and nomenclature for Anotrichium necessitate reexamination of Pacific Mexico 

specimens previously referred to Griffithsia tenuis or A. tenue (e.g., 

Chávez-Barrear, 1972b; Huerta-Múzquiz and Mendoza-González, 

1985; León-Tejera and González-González, 1993).

Sexual thalli of Anotrichium secundum are not known from 

the Gulf of California. Descriptions of gametangial thalli from 

the Hawaiian Islands can be found in Abbott (1999). 

Griffithsia C. Agardh

Griffithsia C. Agardh, 1817:xxviii.

Thalli of erect, uniseriate filaments, subdichotomously or 

rarely subtrichotomously to unilaterally branched to several orders. Cells often relatively large, from cylindrical to oblong or 

globose, and multinucleate, with discoid plastids. Some species 

are constricted at the nodes or moniliform, except at the very 

base. Filaments ecorticate or in some species loosely rhizoidally 

corticated below, attached by rhizoids from the basal cells. Gland 

cells are absent. 

Tetrasporangia are borne, with or without 1-celled involucres (some species with peripheral tetrasporangial fascicles that 

have large flat, ear-like or “curved-lobed” involucres), in groups 

of 2 or more per fascicle. Tetrasporangial fascicles are usually 

numerous and whorled in between the axial cells in apical regions or on the tops of special lateral branches. (One species, G. 

chilensis Montagne in Kützing (1849), is reported with polysporangia; see Hoffmann and Santelices, 1997:344). Gametophytes 

dioecious or occasionally monoecious. Carpogonial branch is of 

3 small discoid cells; the basal cell bearing, abaxially, involucral 

branches each composed of 2(–3) cells, a small lower ovoid cell 

and an upper elongate, incurving cell that forms a cup-like involucre. Spermatangia are in small, densely branched spermatangial 

fascicles, which are whorled between axial cells or clustered in 

a cap terminal on a special lateral branch (after Baldock, 1976). 

One species of Griffithsia is recognized in the northern 

Gulf of California (included in the key under the related genus 

Anotrichium).

Griffithsia pacifica Kylin

FIGURE 144

Griffithsia pacifica Kylin, 1925:58, figs. 38a–d, 39a–g; Smith, 1944:324, pl. 

83: fig.2; Taylor, 1945:268 [with a query]; Dawson et al., 1960a:64, pl. 

36: fig. 3; Dawson, 1961b:444; 1962a:72, pl. 29: fig. 2, pl. 30: fig. 6, 

FIGURE 144. Griffithsia pacifica: A. Habit showing subdichotomous branching (JN-5159, US Alg. Coll. microscope slide 4980). B. Apical cells 

hemispherical to dome-like, trichoblasts absent (JN-5148, US Alg. Coll. microscope slide 4955). 
296 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

pl. 31: figs. 1–4; 1966a:28; Abbott and North, 1972:76; Abbott and 

Hollenberg, 1976:621, fig. 564; Mendoza-González and Mateo-Cid, 

1985:30; Mendoza-González and Mateo-Cid, 1986:425 [with a query]; 

Sánchez-Rodríguez et al., 1989:45; Scagel et al., 1989:189; Stout and 

Dreckmann, 1993:15; Mateo-Cid and Mendoza-González, 1994b:41; 

González-González et al., 1996:220; L. Aguilar-Rosas et al., 2000:131; 

Mateo-Cid et al., 2006:53; Serviere-Zaragoza et al., 2007:10.

Algae 1–2(–5) cm high; axes 300–500 μm in diameter in 

basal through middle portions, becoming narrower, (50–)75–

150 μm in diameter toward apices; regularly subdichotomously 

(sometimes subtrichotomously) branched (occasionally less regular in upper portions). Cells mostly cylindrical, with thick cell 

walls; (3–)5–7 times as long as broad in lower portions of the 

thallus; becoming a little inflated at their distal ends, especially 

in upper portions; apical (terminal) cells often hemispherical or 

elongated hemisphere.

Tetrasporangial fascicles, usually numerous; each fascicle 

with 2 to more tetrahedrally divided tetrasporangia; borne in 

dense whorls in between upper axial cells or cap-like on the top 

of short, lateral branches; the inner fascicles with less elaborate 

involucre, peripheral fascicles with larger, lobed, and curvy, 

somewhat “ear-shaped,” involucres. Gametophytes dioecious. 

Female thalli not known in the northern Gulf. Procarps lateral. 

Carposporophyte with gonimoblasts terminating short laterals; 

surrounded by 2-celled involucral branches, with a small, lower 

cell and an elongate, incurved upper cell that form the cup-like 

involucre. Spermatangia without involucres; on branched fascicles whorled around the distal ends of axial cells. 

Habitat. On rocks, in crevices or tide pools, or epiphytic on larger algae; low intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco to 

Guaymas; San Felipe to Santa Teresa; Sinaloa to Jalisco. Eastern 

Pacific: southern Alaska to Todos Santos, Baja California Sur; Isla 

Clarión (Islas Revillagigedo); Colima to Michoacán; Oaxaca.

Type Locality. Dredged off Turn Island, east of Friday Harbor, San Juan Island, San Juan County, Washington, USA.

Wrangeliaceae tribus Spermothamnieae

Wrangeliaceae tribus Spermothamnieae F. Schmitz, 1889:449. 

Ceramiaceae tribus Spermothamnieae F. Schmitz, in Schmitz and Hauptfleisch, 1897b:485; Gordon, 1972:112; Womersley, 1998:208.

Algae are composed of erect, sparingly to moderately 

branched, uncorticated filaments that arise from prostrate filaments attached to substratum or other algae by haptera. Cells 

are multinucleate. 

Life histories, where known, are of isomorphic tetrasporophytes and monoecious or dioecious gametophytes. Tetrasporangia are sessile or pedicellate on the erect filaments. Procarps are 

developed on a subapical cell of a fertile axis, within a gelatinous 

sheath with associated sterile cells, which remain undivided after 

fertilization in most, or may divide to form erect filaments in 

small groups or a loose pericarp-like layer of filaments. Spermatangia are produced in compact clusters.

Two genera of the tribe Spermothamnieae are known to 

occur in the northern Gulf of California.

KEY TO THE GENERA OF THE SPERMOTHAMNIEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Carposporophyte with inner involucral filaments that form a pericarp-like layer of associated filaments within a gelatinous sheath, with an ostiole . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Lejolisia

1b. Carposporophyte without inner or outer involucral filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tiffaniella

Lejolisia Bornet 

Lejolisia Bornet, 1859:91.

Algae are small, composed of erect monosiphonous, uncorticated, simple or irregularly branched filaments that arise from 

spreading prostrate filaments attached by unicellular rhizoidal 

haptera that terminate in digitate or irregular expanded discs. 

Cells are multinucleate.

Tetrasporangia tetrahedrally divided and borne terminally 

on pedicels or borne laterally off erect filaments. Gametophytes 

are dioecious. Carpogonial branch is 4-celled and borne on 

a supporting cell of 3 pericentral cells. Auxiliary cell is cut 

off from the supporting cell and develops a carposporophyte 

with a stellate fusion cell that divides to develop a terminal 

gonimoblast initials that in turn produces chains of gonimoblast cells and terminal carposporangia. The carposporophyte 

is surrounded by erect inner involucre filaments forming a 

loose pericarp-like structure of 1 layer of cells issued from 

sterile cells associated with the procarp, all enclosed in a gelatinous sheath. Spermatangia develop in short, subspherical 

to elongate spermatangial heads that are terminal on short 

laterals.

Two species of Lejolisia, one of which is endemic, are known 

in the northern Gulf of California.

KEY TO THE SPECIES OF LEJOLISIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Erect filaments about 18 μm in diameter; tetrasporangia oval, 42 μm long, 28 μm in diameter, on short, lateral branchlets 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. colombiana

1b. Erect filaments 25–30 μm in diameter; tetrasporangia subspherical, 65 μm long, 50 μm in diameter, sessile on branches 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. hoshawii
NUMBER 96 • 297

Lejolisia colombiana W. R. Taylor

Lejolisia colombiana W. R. Taylor, 1945:265, pl. 4: figs. 3–10; Dawson, 

1962a:43, pl. 17: figs. 1–5; 1962b:186, fig. 41; González-González 

et al., 1996:235; Mateo-Cid et al., 2000:66; Mateo-Cid et al., 

2006:57; Littler and Littler, 2010:[4 figs.]; Fernández-García et al., 

2011:63.

Algae forming small tufts, 3–5 mm tall, of erect and prostrate, uniseriate filaments; cells of erect filaments about 18 μm 

in diameter, lower cells about 100 μm long, upper cells 70 μm 

long; filaments simple (unbranched) or sparingly branched, alternate or rarely unilateral; terminating with long cells with an 

obtuse apex; erect filaments arising on dorsal side of cells of 

basal stoloniferous filaments, stoloniferous filaments to 24 μm 

in diameter. 

Tetrasporangia oval, tetrahedrally divided, 42 μm long, 28 

μm in diameter; borne terminal on a short, 1- to 2-celled, upcurved, lateral branch of erect branches. Cystocarps turbinate, 

138–150 μm long, 110–175 μm in diameter, surrounded by a 

pericarp-like cellular layer (see Dawson, 1962a: pl. 17: fig. 5); 

borne terminal on erect branches or on lateral branchlet of a 

few cells. Spermatangia in cylindrical-oval clusters, (80–)100–

115 μm long, 35 μm in diameter (description after Taylor, 1945; 

Dawson, 1962a).

Habitat. On rocks and probably tidal platform;

intertidal.

Distribution. Gulf of California: Puerto Peñasco; 

Cabeza Ballena to Cabo Pulmo. Eastern Pacific: Isla Gorgona, 

Colombia.

Type Locality. Isla Gorgona (Parque Nacional 

Natural Isla Gorgona), Departamento de Valle del Cauca, Pacific 

Colombia. 

Remarks. Known in the southern Gulf of California 

(Dawson, 1962a), Lejolisia colombiana was more recently reported in the upper Gulf by Mateo-Cid et al. (2006).

Lejolisia hoshawii E. Y. Dawson

FIGURE 145

Lejolisia hoshawii E. Y. Dawson, 1966b:64, fig. 6J,K; GonzálezGonzález et al., 1996:236; CONANP, 2002:138; Mateo-Cid et al., 

2006:52.

Lejolisia sp. nov. sensu Dawson, 1966a:26; Mateo-Cid et al., 2006:52.

Thalli epiphytic, about 7 mm tall, composed of uniseriate, 

prostrate, and erect filaments. Creeping prostrate filaments attached by short, unicellular rhizoids terminating in expanded 

digitate discs. Axial cells of filaments 30–50 μm in diameter and 

85–150 μm in length. Erect filaments sparsely branched except 

in fertile plants, with blunt tips; issued from prostrate filaments, 

up to 5–7 mm long.

Tetrasporangia tetrahedrally divided, 65 μm long by 50 μm 

wide (including thick hyaline envelope). Tetrasporangia sessile 

on diminutive protuberance of the bearing cell of erect filaments, 

solitary or a few multifariously positioned on successive cells. 

Sexual reproduction unknown.

Habitat. Epiphytic on larger algae; shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena.

Type Locality. On Sargassum in drift, Playa Hermosa, Puerto Peñasco, Sonora, Gulf of California, Mexico.

Tiffaniella Doty et Meñez

Tiffaniella Doty et Meñez, 1960:135.

Algae are small tufts, composed of erect and prostrate, uniseriate, uncorticated filaments. The erect filaments are slender 

and unbranched or irregularly, unilaterally or subdichotomously 

branched axes that arise from the prostrate, spreading filaments 

that attach by rhizoids on their ventral side. Attachment rhizoids 

are frequent and simple (unbranched); in some species they are 

modified by swelling (becoming saccate) or with extensive digitate ends. Cells are multinucleate. 

Sporangia are in lateral clusters or solitary and terminal on 

short stalks. They are tetrahedrally divided to form tetrasporangia (4 spores) or polyhedrally divided, forming polysporangia, 

each containing from 8 to 64 spores. Gametophytes are monoecious or dioecious; procarps subapical on laterals of erect axes. 

Carpogonial branches are 4-celled and borne on 1 (supporting 

cell) of 3 pericentral cells, with the other 2 producing auxiliary 

cells. Carposporophyte is developed by 2 auxiliary cells fusing to 

fertile axis cell, forming the characteristic T-shaped fusion cell, 

involving the hypogenous cell. Involucral filaments are absent, 

leaving the carposporophyte naked. Spermatangia form elongate 

heads that are sessile or pedicellate on short laterals from erect 

filaments. 

Remarks. Mostly epiphytic or endophytic, species 

of Tiffaniella are widespread in distribution. The “Spermothamnion sp.” of Ortega et al. (1987) from Laguna Agiabampo 

should be reexamined and may possibly be a Tiffaniella.

There are three species of Tiffaniella known in the northern 

Gulf of California. 

FIGURE 145. Lejolisia hoshawii (holotype): A. Tetrasporangia 

borne on erect filaments. B. Portion of creeping filament to show 

attachment structures and erect axes (A, B, after Dawson, 1966b: 

figs. 6J, K).
298 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

KEY TO THE SPECIES OF TIFFANIELLA IN THE NORTHERN GULF OF CALIFORNIA

1a. Erect filaments subdichotomously branched, rhizoids unicellular, often with markedly modified inflated rhizoids, swollen 

in middle and terminating in irregular saccate swelling or swollen cylinders ending in digitate disc, rhizoids 300–500 μm 

long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . T. saccorhiza

1b. Erect filaments sparsely, unilaterally or irregularly branched, rhizoids not swollen but may terminate in digitate attachment discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Erect filaments to 5 mm tall; sparingly branched; slender, 35–75 μm in diameter, attenuated upward, becoming thinner 

in diameter, (12–)18–25 μm near apices; sporophytes with tetrasporangia, 50–70 μm in diameter . . . . T. phycophilum

2b. Erect filaments taller ( >5 mm); more branched; filaments thicker, 50–110 μm in diameter, all orders of branches nearly 

same diameter throughout; sporophytes with polysporangia (75–120 μm in diameter) . . . . . . . . . . . . . . . . T. snyderae

Tiffaniella phycophilum (W. R. Taylor) E. M. Gordon

Spermothamnion phycophilum W. R. Taylor, 1945:263, pl. 3:figs. 17–

21, pl 4: figs. 1, 2; Dawson, 1961b:444; González-González et al., 

1996:271.

Tiffaniella phycophilum (W. R. Taylor) E. M. Gordon, 1972:125; Abbott 

and Hollenberg, 1976:623, fig. 565; Stewart and Stewart, 1984:146; 

Sánchez-Rodríguez et al., 1989:45; González-González et al., 1996:272; 

CONANP, 2002:138.

Spermothamnion snyderae var. attenuata E. Y. Dawson, 1962a:45.

Algae forming short, spreading turfs, 3–5 mm high; of erect, 

unbranched or sparingly, alternately branched filaments arising 

from creeping, prostrate filaments attached on the ventral side 

by unicellular rhizoids. Axial cells 70–225 μm long (mostly 2–3 

times longer than diameter), 35–75 μm in diameter; near apices, 

axial cells smaller, 25–40 μm in diameter, with obtusely rounded, 

blunt apices. Prostrate filaments mostly 30–60 μm in diameter. 

Rhizoids rarely long but can be up to 400 μm.

Tetrasporangia tetrahedrally divided, subspherical, 50–70 

μm in diameter; solitary at first, on upcurved stalks that rebranch 

from below and successively develop clusters of tetrasporangia; 

borne unilateral in a series or occasionally opposite on erect filaments. Gametophytes dioecious. Carposporangia in cluster without involucres. Spermatangia heads sessile, unilateral in a series 

on erect filaments.

Habitat. Epiphytic on other algae; low intertidal to 

shallow subtidal, down to 6 m depths.

Distribution. Gulf of California: Bahía de Loreto. 

Eastern Pacific: Santa Catalina Island (California Channel Islands); Isla Guadalupe (off Baja California) to Bahía Magdalena 

(Baja California Sur); Galápagos Islands.

Type Locality. Black Beach, Isla Santa María (Isla 

Floreana; Charles Island), Galápagos Islands, Ecuador.

Tiffaniella saccorhiza (Setchell et N. L. Gardner) Doty et 

Meñez

FIGURE 146A,B

Pleonosporium saccorhiza Setchell et N. L. Gardner, 1930:169, pl. 10: 

fig. 39.

Tiffaniella saccorhiza (Setchell et N. L. Gardner) Doty et Meñez, 1960:138, 

figs. 1–4; Dawson, 1961b:444; 1962a:44, pl. 16: fig. 2; 1966a: front 

cover illustration, 28; Stewart and Stewart, 1984:146; Mateo-Cid and 

Mendoza-González, 1992:22; Mateo-Cid et al., 1993:48; ServiereZaragoza et al., 1993a:484; Mateo-Cid and Mendoza-González, 

1994b:41; González-González et al., 1996:272; Abbott, 1999:315, fig. 

88C–E; Mateo-Cid et al., 2006:53.

Spermothamnion saccorhiza (Setchell et N. L. Gardner) Feldmann-Mazoyer, 

1942:16; Dawson, 1954e:343; González-González et al., 1996:271.

Erect axes, unbranched or subdichotomous to irregularly 

branched (up to 2–3 orders); axial cells slender, 26–30 μm in 

diameter, 200–360 μm long; arising from creeping prostrate axes 

of shorter cells; attached to the host by rhizoids that are often 

distinctive. Rhizoids, pigmented and unicellular, of various morphologies: expanded (swollen) in middle up to 65 μm in diameter 

and 300–500 μm long, with either irregular saccate ends or blunt 

unmodified ends; or thin to inflated cylinders with unmodified, 

digitate or discoid ends.

Polysporangia borne on short upcurved lateral branches, 

single or several in small group, oblong, about 75–85 μm, surrounded by thick cell wall. Cystocarps small and lack involucres. 

Spermatangia in obovate heads, solitary, heads terminal or lateral.

Habitat. Epiphytic on Codium and other algae; mid 

intertidal to shallow subtidal, down to 9 m depth.

Distribution. Gulf of California: Playa Arenosa 

(Sandy or Norse Beach), Puerto Peñasco to Bahía de Los Ángeles; Bahía Concepción. Eastern Pacific: Isla Guadalupe; Bahía Sebastián Vizcaíno to Todos Santos, Baja California Sur; Nayarit. 

Central Pacific: Hawaiian Islands. 

Type Locality. Epiphytic on Codium sp.; Isla Guadalupe, Baja California, Pacific Mexico.

Remarks. In the field, Tiffaniella saccorhiza can 

often been seen as pink-reddish fuzz growing on species of Codium. It is the generitype of Tiffaniella.

Tiffaniella snyderae (Farlow) I. A. Abbott

FIGURE 146C,D

Spermothamnion snyderae Farlow, 1899:74 [as “snyderiae”]; Drew, 

1937:463, figs. 1, 2, pl. 21; Smith, 1944:322, pl. 82: figs. 3–5; Dawson, 

1945d:67; 1949c:220; 1950b:155, figs. 24, 25; 1951:53; Dawson et 

al., 1960a:80, pl. 36: figs. 1, 2; Dawson, 1961b:444; 1962a:45, pl. 16: 

figs. 3–5; 1966a:27; Norris and West, 1966:177; González-González et 

al., 1996:271.

Tiffaniella snyderae (Farlow) I. A. Abbott, 1971:352, figs. 1f, 2a,b; Abbott and Hollenberg, 1976:624, fig. 566; Devinny, 1978:360; Silva, 

1979:328; Pacheco-Ruíz and Aguilar-Rosas, 1984:73; Scagel et al., 
NUMBER 96 • 299

FIGURE 146. Species of Tiffaniella. A, B. Tiffaniella saccorhiza: A. Erect filaments arising from creeping portion attached by distinctive inflated 

rhizoids. B. Polysporangia on lateral branches off erect filaments (A, B, EYD-46-1330, US Alg. Coll. microscope slide 917). C, D. Tiffaniella 

snyderae: C. Erect filaments arising from creeping portion showing rhizoids. D. A group of developing polysporangia (C, D, after Dawson, 

1962a: pl. 16: figs. 4, 3).
300 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

1989:262; Stewart, 1991:137; Ramírez and Santelices, 1991:332; 

R. Aguilar-Rosas and Aguilar-Rosas, 1994:523; Hoffmann and Santelices, 1997:349, pl. 96: figs. 1–4; González-González et al., 1996:272.

Algae of uniseriate, uncorticated filaments, forming erect 

tufts or sometimes mats, mostly 1–3 mm high; differentiated 

into creeping prostrate axes and erect branches; attached below 

by unicellular rhizoids that terminate in expanded digitate discs. 

Axes and branches of nearly uniform diameter, slightly thinner in 

upper portions of thallus; erect branches more or less uniform in 

height. Axial cells cylindrical, 40–70(–110) μm in diameter and 

(100–)350–1000 μm long. Erect axes predominately unilaterally 

branched, sometimes irregularly; usually branched 1–3 orders; 

apical cells blunt.

Polysporangia broadly ellipsoidal, 95–130 μm long, 75–120 

μm in diameter, borne terminally on short, simple or compound 

branchlets, usually in lateral clusters (occasionally single) off 

erect axes; with (8–)12–16(–32) polyspores. Gametophytes dioecious. Carposporophyte reported as an ovate, loose cluster of 

carpospores, about 350 μm in diameter; without an involucre. 

Spermatangia forming cylindrical, compact heads, about 150 μm 

long, 50 μm in diameter; sessile on short, simple or compound, 

incurved branchlets in lateral clusters off erect axes. 

Habitat. On rocks and in tide pools, epizoic on 

sponge or epiphytic on other larger algae; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Puerto Libertad; Isla San Jorge; Ensenada de San Francisco 

(vicinity of Guaymas). Eastern Pacific: Aleutian Islands, Alaska 

to Isla Santa Margarita (barrier island of Bahía Magdalena), 

Baja California Sur; Chile.

Type Locality. Syntype localities: Santa Cruz, 

Santa Barbara, and San Diego, California, listed by Farlow 

(1899:75). Lectotype locality: Santa Cruz, Santa Cruz County, 

California, USA (Smith, 1944:323). 

Remarks. Dawson (1962a, as Spermothamnion snyderae) suggested that in the northern Gulf Tiffaniella snyderae was 

a winter annual. Our collections seem to support Dawson, as we 

found T. snyderae only during the winter months from November to 

March (1972–1976). Our specimens were all nonreproductive; the 

descriptions of reproductive structures are after Dawson (1962a). 

Wrangeliaceae tribus Spongoclonieae

Wrangeliaceae tribus Spongoclonieae F. Schmitz, 1889:450.

The tribe Spongoclonieae is represented by one genus in the 

northern Gulf of California.

Pleonosporium Nägeli 

Pleonosporium Nägeli, 1862:326, 339.

Algae are erect, uniseriate branched filaments, and usually 

epiphytic; attached to substrate by rhizoids, at times terminating 

in digitate discs. Main axes are alternately branched and spirally, 

radially, or distichously arranged. Axes are completely uncorticated or partly corticated by descending rhizoids. Laterals, one 

per segment (axial cell), are simple or unilaterally, pinnately, alternately, or irregularly branched, 1–4(–5) orders. Gland cells are 

absent. Cells are multinucleate.

Asexual reproduction is by polysporangia or tetrasporangia. 

Polysporangia are sessile or pedicellate and borne adaxial and secund or alternately in abaxial and adaxial sequence along lateral 

branchlets. Tetrasporangia are tetrahedrally divided, sessile or 

pedicellate, and borne on branchlet cells. Gametophytes are dioecious. Procarps are subapical on differentiated fertile axes. Cystocarps of one or more round masses of carposporangia are naked 

or surrounded by one to several involucral branches. Spermatangia, forming oblong to cylindrical heads, are on special short 

branchlets that are borne unilaterally (adaxially) or alternately (in 

a sequence, adaxial to abaxial) or terminal on branchlets.

Remarks. There is one species reported in the southern Gulf: Pleonosporium squarrulosum (Harvey) I. A. Abbott 

(1972; basionym: Callithamnion squarrulosum Harvey, 1853; 

synonym: Pleonosporium dasyoides (J. Agardh) De Toni, 1903; 

see Dawson, 1962a) from Bahía de Loreto (CONANP, 2002).

Four species of Pleonosporium occur in the northern Gulf 

of California.

KEY TO THE SPECIES OF PLEONOSPORIUM IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli with alternately radial branching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. globuliferum

1b. Thalli with alternately distichous branching . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Determinate branchlets alternately branched, polysporangia and spermatangia arranged alternately on adaxial and 

abaxial sides; polysporangia divided into about 16 spores . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. vancouverianum

2b. Determinate branchlets usually simple; polysporangia divided into about 32 spores . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Lower portions abundant with more or less loosely entangled descending rhizoids; polysporangia spherical, sessile and 

alternate, grouped on short, irregular, specialized, densely branched polysporangial branchlet system . . . . . P. rhizoideum

3b. Lower portions not noticeably clothed with rhizoids; polysporangia ovoid, seriate, sessile and adaxial on determinate 

lateral branchlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. mexicanum

Pleonosporium globuliferum Levring

FIGURE 147

Pleonosporium globuliferum Levring, 1941:647, fig. 19; Dawson, 1957c:21; 

1960a:50; 1961b:443; 1962a:41, pl. 15: fig. 2–6; Navas, 1966:112, pl. 

8: fig. 4A–C; Stewart and Stewart, 1984:145; Sánchez-Rodríguez et al., 

1989:45; Ramírez and Santelices, 1991:329; González-González et al., 

1996:250; Mateo-Cid et al., 2000:66; Bernecker, 2009:CD-Rom p. 65; 

Fernández-García et al., 2011:62.
NUMBER 96 • 301

Thalli of several uncorticated erect axes, up to 1.5 cm tall, 

alternately and multifariously radially, spirally branched; attached by multicellular rhizoids, often terminating in digitate attachment discs. Axial cells up to 200–400 μm long and to 100 

μm in diameter basally (2–4 times longer than wide). Branchlets 

alternately divided, upcurved, about 30 μm in diameter at their 

base, with cells 2–3 times as long as wide (60–90 μm long). Tips 

of ultimate branchlet cells blunt, up to 14 μm diameter.

Polysporangia 28–45(–70) μm in diameter, subspherical, 

sessile, and scattered (infrequently in a short series) along lateral 

branches, 1 to a cell. Spermatangial heads oblong, to 75 μm long 

and to 30 μm in diameter, sessile and adaxial on the ultimate 

branchlets, 1 per cell, usually on the proximal cells of branchlets, 

in upper portions of the thallus. 

Habitat. Epiphytic on Codium and Sargassum or 

entangled with other algae; intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco; 

Cabo Pulmo to San José del Cabo. Eastern Pacific: Isla Guadalupe (off Baja California); Oaxaca; El Salvador; Costa Rica; 

Chile.

Type Locality. Sta. 13, “Ausserhalb Sanchez, Masafuera” (Levring, 1941:604, 647); Quebrada Sánchez, Isla Alejandro Selkirk (Más Afuera), Islas Juan Fernandez, Valparaiso 

Region, Chile.

FIGURE 147. Pleonosporium globuliferum: A. Habit showing multifarious branching. B. Adaxial polysporangia; note the rhizoids (arrows) 

from some of the axial cells (JN-7175, US Alg. Coll. microscope slide 4673). C. Upper portion of axis showing serial, adaxial arrangement of 

cylindrical spermatangial heads (A, C, JN-4147, US Alg. Coll. microscope slide 4682). 
302 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Pleonosporium mexicanum E. Y. Dawson

FIGURE 148

Pleonosporium mexicanum E. Y. Dawson, 1962a:41, pl. 16, fig 1; 1966a:26; 

1966b:65; Stewart and Stewart, 1984:145; Dreckmann et al., 1990:32, 

pl. 6: fig. 2; Serviere-Zaragoza et al., 1993a:484; González-González 

et al., 1996:250; CONANP, 2002:138; Pacheco-Ruíz et al., 2008:211; 

Fernández-García et al., 2011:62.

Thalli erect, to 2 cm tall, composed of several uncorticated 

axes. Distichous and alternately branched; richly branched in 

upper parts, but not from every cell in lower parts. Axial cells of 

primary axes 110–225 μm in diameter basally, and cells longest 

in middle portions (2–4 times the diameter long), reduced in both 

dimensions above. Attached by long, little-divided multicellular 

rhizoids. Most determinate branchlets unbranched, from 15–30 

cells long, somewhat incurved and corymbose. Cells of branchlets 40–60 μm in diameter at their base and about 1.5 times as 

long, ultimate cells blunt tipped and about 25 μm in diameter.

Polysporangia ovoid, 70–90 μm in diameter when hyaline 

envelope is included. Polysporangia borne sessile and adaxial on 

determinate branchlets, in a series, 1 per cell toward distal end of 

cell. Polysporangia divided into about 32 spores. Sexual reproduction not seen.

Habitat. Epiphytic or saxicolous; low intertidal to 

subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía Bocochibampo (near Guaymas); Cabo San Lucas; 

Mazatlán, Sinaloa to Nayarit. Eastern Pacific: Isla Guadalupe; El 

Salvador; Costa Rica.

Type Locality. Lowermost intertidal on small reef, 

3 km north of Belmar Hotel; Playa de Olas Atlas, vicinity of 

Mazatlán, Sinaloa, Gulf of California, Mexico.

Remarks. Although some Pleonosporium mexicanum can be somewhat vegetatively similar to members of the 

Callithamnion rupicola-uncinatum complex, members of the latter complex do not have polysporangia.

Pleonosporium rhizoideum E. Y. Dawson

Pleonosporium rhizoideum E. Y. Dawson, 1962a:42, pl. 14: figs. 1–3, pl. 17: 

fig. 7; Mendoza-González et al., 1994:108; González-González et al., 

1996:250, fig. 36; Mateo-Cid et al., 2006:57.

FIGURE 148. Pleonosporium mexicanum: A. Upper portion of axis showing distichous alternately arranged determinate branchlets 

bearing sessile polysporangia adaxially, in a series. B. Branchlet with developing and mature polysporangia (A, B, holotype, EYD3610, US Alg. Coll. microscope slide 398).
NUMBER 96 • 303

Thalli erect tufts, up to 2.5 cm tall; composed of uncorticated axes, 125–170 μm in diameter basally, (125–)180–340 μm 

long (about [1–]1.5–2.0 times as long as diameter); more or less 

loosely clothed in lower potions by entangled rhizoids (see Dawson, 1962a: pl. 17: fig. 7); more or less distichously branched. 

Branches mostly simple, 60–70 μm in diameter, long and initially 

incurved, later becoming recurved or irregularly curved, little attenuated; terminating in blunt apices (sometimes prolonged to 

form a rhizoid). Basal felt-like attachment composed of numerous, descending rhizoids.

Polysporangia spherical, divided into about 32 spores; 

about 60 μm in diameter; sessile and alternate, borne in groups 

on specialized, short, irregular branches in densely branched 

portions of thallus. Cystocarps subspherical, about 90 μm in 

diameter, with several low irregular lobes; borne in densely 

branched fertile portions (similar to those of sporangial 

thalli). Spermatangia not known (description after Dawson, 

1962a).

Distribution. Gulf of California: Puerto Peñasco; 

Mazátlan. Eastern Pacific: Oaxaca.

Type Locality. Salina Cruz, Oaxaca, Pacific Mexico.

Remarks. Pleonosporium rhizoideum was reported 

in the upper Gulf of California by Mateo-Cid et al. (2006); since 

I have not seen their specimens, the description is based on Dawson (1962a).

Pleonosporium vancouverianum (J. Agardh) J. Agardh

FIGURE 149

Callithamnion vancouverianum J. Agardh, 1876:30.

Pleonosporium vancouverianum (J. Agardh) J. Agardh, 1892:37; Kylin, 

1925:57, fig. 37A–C; Smith, 1944:321, pl. 82: figs. 1, 2; Dawson, 

1961b:444; Dawson and Neushul, 1966:182; Hollenberg and Abbott, 1966:101; Abbott and Hollenberg, 1976:620, fig. 562; Devinny, 

1978:359; Stewart and Stewart, 1984:145; Scagel et al., 1989:228; 

R. Aguilar-Rosas et al., 1990:126; González-González et al., 1996:250.

Pleonosporium abysicola N. L. Gardner, 1927d:380, pl. 81: fig. 1, pl. 82; 

Dawson, 1961b:443; 1962a:39, pl. 13: fig. 3; Dawson and Neushul, 

1966:182; Huerta-Múzquiz, 1978:339; Mateo-Cid and MendozaGonzález, 1992:21; González-González et al., 1996:249.

Thalli uniseriate filaments, of several erect axes, up to 

1.0(–1.8) cm tall, distichous and repeatedly regularly alternately 

branched to 4(–5) orders; branching from almost every cell, each 

order progressively smaller than proceeding one. Axes uncorticated, percurrent, axial cells of primary axes cylindrical, basally 

150–240 μm diameter and to 340–680 μm long, smaller above 

and cuboid. Proximal cell of laterals slightly shorter than adjoining cells. Algae attached by a few wide filament-like rhizoids at 

axes base and by long, thin (to 20 μm in diameter), unbranched, 

uniseriate, multicellular rhizoids issued singly, from the middle 

of some lower axial cells. Ultimate branchlets of 2–6 cells, ultimate cells blunt tipped, about 10 μm in diameter.

FIGURE 149. Pleonosporium vancouverianum: A. Alternate adaxial-abaxial arrangement of polysporangia along branchlet. B. Upper portion 

of axis showing alternate, distichous branching pattern (JN-4745, US Alg. Coll. microscope slide 4690). C. Alternately distichously branched to 

several orders, cells diminishing in width and length at each order (A, C, JN-4745, US Alg. Coll. microscope slide 4689).
304 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Mature polysporangia ovate to oblong-ellipsoidal, to 75 

μm long and to 45 μm wide, divided into about 16 spores; sessile, borne alternately in position of ultimate branchlets. Sexual 

plants not found in Gulf of California material. Elsewhere reported: carposporophytes involucrate; spermatangia in short, 

ovoid heads, sessile or pedicellate, borne alternately in position 

of ultimate branchlets. 

Habitat. Epiphytic or entangled with larger algae; 

shallow subtidal, down to 20 m depths.

Distribution. Gulf of California: Isla Coronado 

(Isla Smith) and Islas de Los Gemelos (Islas los Hermanitos), 

both off Bahía de Los Ángeles; Nayarit. Eastern Pacific: Vancouver Island, British Columbia, to Santa Cruz Island (California Channel Islands); Islas Todos Santos and Isla Guadalupe, off 

Baja California; Isla Magdalena (west side of Bahía Magdalena), 

Baja California Sur.

Type Locality. Vancouver Island, British Columbia, Canada.

Remarks. Apparently rare in occurrence, the collection of subtidal specimens of Pleonosporium vancouverianum at 

Isla Coronado (JN-4419, US Alg. Coll. microscope slide 4687) 

and Islas de Los Gemelos, Bahía de Los Ángeles (JN-4745, US 

Alg. Coll. microscope slide 4689–4691) represent new distribution records for the Gulf of California. 

Gelidiales*

Gelidiales Kylin, 1923:132; Hommersand and Fredericq, 1998:254 [revised 

description].

Members of this order are erect individuals or few to many 

in tufts or clumps or form cushions or turfs or spreading mats; 

they are composed of cylindrical to compressed branching axes 

and branches, developing from prostrate axes. Most are freely 

branched in one plane, but some branch in various directions. 

The uprights develop from prostrate axes, which are generally 

subcylindrical to slightly compressed and less pigmented than 

the erect parts. The lower prostrate axes are often entangled 

and attach the alga to the substratum at various intervals by 

either (1) thick-walled rhizoidal filaments developed from the 

surface cortical layer (Gelidiellaceae), (2) brush-like holdfasts of 

independent (not coalescing) thick-walled unicellular rhizoidal 

filaments developed from the inner cortical cells and pigmented 

multicellular uniseriate filaments from the surface cells (Gelidiaceae), or (3) peg-like holdfasts of coalescing (into a thick sheath) 

thick-walled, unicellular rhizoidal filaments from the inner 

cortical cells and pigmented multicellular uniseriate filaments 

(Pterocladiaceae).

* Contributed by James N. Norris and Joan G. Stewart. J. G. Stewart: 

Scripps Institution of Oceanography, University of California, San 

Diego, La Jolla, California, USA.

All of the species are uniaxial, with a usually distinct apical 

cell. In transection the single axial filament is often obscured by 

longitudinal filaments, which develop around it from the inner 

cortex. The medulla is composed of large longitudinal cells that 

are sparsely to densely entwined with internal rhizoidal filaments 

(rhizines, or hyphae) and a cortex of successively smaller cells 

toward the surface. 

Tetrasporophytes and gametophytes are isomorphic. Tetrasporangial thalli have tetrasporangia embedded beneath 

the surface of branchlets. Carpogonial branches are one- to 

three-celled and deeply embedded in the cortex. Carpogonia 

are intercalary, developed within branchlets. Gonimoblasts 

are produced either from the fertilized carpogonia, which in 

turn fuses with the hypogynous cells, or from the long nutritive 

filaments, which develop from the fusion cells following fertilization. Auxiliary cells are absent in this order. Cystocarps are 

bilocular and protrude with ostioles on both sides of the blade, 

with a conspicuous bulge on only one surface of a branch. Spermatangia are developed in superficial sori below branch and 

branchlet apices.

Remarks. In the field some of the smaller Gelidiales 

in the Gulf of California could be confused with Gulf Wurdemannia miniata (Sprengel) J. Feldmann et G. Hamel and some 

very small specimens of Gulf Ceratodictyon tenuis (Setchell et 

N. L. Gardner) J. N. Norris (herein). In the families of Gelidiales, 

species are uniaxial (apical usually evident), semirigid to cartilaginous (mostly over 250 μm in diameter); tetrasporangia are 

cruciately, tetrahedrally, or irregularly divided, and elongated, 

internal rhizoidal filaments (rhizines, hyphae) are present among 

the medullary cells (and sometimes cortical cells) of Gelidiaceae 

and Pterocladiaceae but are absent in the Gelidiellaceae. In contrast, both Ceratodictyon (Lomentariaceae) and Wurdemannia

(Solieriaceae) are multiaxial, rigid, wiry (mostly less than 250 

μm in diameter), and internal rhizoidal filaments are absent; and 

the tetrasporangia are zonately divided in Wurdemannia and 

cruciately divided in Ceratodictyon.

It has long been considered difficult to distinguish the genera 

of many Gelidiales (especially in absence of cystocarpic material) 

and, in many cases, the species. Their taxonomy has been complicated by a high degree of morphological plasticity, and the unreliability of using the branching pattern as a character makes it 

difficult to recognize discrete taxa and understand species limits. 

Several recent studies have supported the usefulness of anatomical characters in separating the families; for example, the internal 

rhizoidal filaments (also referred to as “rhizines” or “hyphae”) 

among the medullary cells and/or in the cortex are present in 

members of the Gelidiaceae and Pterocladiaceae but absent in the 

Gelidiellaceae. Perrone (1994), Shimada et al. (1999), and Perrone et al. (2006) described different kinds of attachment structures that also helped to separate the families: brush-like haptera 

in the Gelidiaceae and peg-like haptera in the Pterocladiaceae. 

More recently, Santelices (2007) tested these attachment characters and found support for the Perrone et al. (2006) hypothesis 

that the kind of attachment is unique to each family.
NUMBER 96 • 305

KEY TO THE FAMILIES OF GELIDIALES IN THE NORTHERN GULF OF CALIFORNIA

1a. Anatomically, species completely lack internal rhizoidal filaments (hyphae, rhizines); thalli adhere to or penetrate substratum by single-celled rhizoids originating from outer cortical cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gelidiellaceae

1b. Anatomically, internal rhizoidal filaments among medullary cells and/or cortical cells (sometimes not apparent or lacking in small thalli); prostrate axes of thalli attached to substratum by haptera-like structures of two kinds of filaments: 

(1) unicellular, colorless rhizoidal filaments produced from inner cortical cells that protrude between surface cells and 

(2) multicellular, pigmented uniseriate filaments that develop from the outer (surface) cortical cells . . . . . . . . . . . . . . . 2

2a. Brush-like haptera; of internal rhizoidal filaments growing independently (remain free; not coalescing) between surface 

cells and pigmented, multicellular filaments developed from surface cells that form basal cortication . . . . . Gelidiaceae

2b. Peg-like attachment haptera; of internal rhizoidal filaments growing between surface cells and coalescing in a thick sheath 

and pigmented multicellular filaments from surface cells that form a basal cortication . . . . . . . . . . . . . . Pterocladiaceae

Gelidiaceae

Gelidiaceae Kützing, 1843:390, 405 [as “Gelidieae”]; Perrone et al., 2006:31 

[emended description].

Algae are composed of erect, terete, compressed or flattened, slender to narrow axes that are sparsely to densely and 

pinnately to irregularly branched (rarely unbranched). Uprights 

develop from a prostrate system of often entangled, irregularly 

branched, terete to compressed axes, opposite the small brushlike haptera of rhizoidal filaments and pigmented filaments 

that group together but remain single (do not coalesce) and 

adhere to or penetrate the substratum. The brush-like haptera are composed of two kinds of noncoalescing filaments: 

thick-walled, refractive, colorless rhizoidal filaments originating internally from inner cortical cells that grow independently 

and protrude between the surface cells and pigmented, multicellular, uniseriate filaments developed externally from the 

surface cells. 

Growth is uniaxial. Internally, there are few to many thickwalled, refractive unicellular internal rhizoidal filaments (rhizines 

or hyphae), originating from the inner cortical cells and growing 

basipetally, obliquely or transversally through the thallus. 

Life histories, where known, are generally triphasic (more 

rarely biphasic), with isomorphic tetrasporophytes and gametophytes. Tetrasporangia are cruciately or tetrahedrally divided and 

in sori in branchlet tips or scattered in ultimate branchlets. Tetraspores usually have an ordered arrangement in parallel rows in 

young sori, whereas mature tetrasporangia are either irregularly 

arranged or in parallel rows. Gametophytes are mostly dioecious 

or sometimes monoecious. Cystocarps are bilocular, within and 

raised or protruding above the surface of ultimate branchlets or 

either terminal or below on the branches. Spermatangia develop 

in sori, forming superficial colorless patches on upper branches 

and ultimate branchlets. 

There are currently nine genera recognized in the Gelidiaceae; one of these, Gelidium, is found in the Gulf of California.

Gelidium J. V. Lamouroux 

Gelidium J. V. Lamouroux, 1813:128.

Acropeltis Montagne, 1837:355.

Algae are erect, semirigid and cartilaginous, terete, subterete, or compressed, upright axes that arise from unbranched to 

branched prostrate axes. Thallus morphology is varied, and species may be turf mats with extensive prostrate axes, in tufts, or 

discrete clumps composed of one to several branched axes. The 

uprights are narrow and distichously, plumosely, or irregularly 

branched, often with branches regularly arranged and bilaterally 

symmetrical. Color is variable between and within species, ranging from yellowish green, red, or dark purple to nearly black; 

color is partly related to the degree of solar and tidal exposure 

in an individual’s habitat. They are attached to or penetrate the 

substratum by characteristic short, brush-like haptera along the 

prostrate axes. These are composed of independent (not coalescing), colorless rhizoidal filaments that develop from the inner 

cortical cells and grow outward between the surface cortical cells 

and, together with pigmented, multicellular, uniseriate filaments 

produced from the outer (surface) cortical cells, form short, 

brush-like attachments. 

Growth is uniaxial, and a single apical cell is usually evident. 

The medulla is usually compressed, composed of rounded, colorless cells; in transection it is up to 30 μm in diameter. Elongated 

internal rhizoidal filaments (rhizines or hyphae) are interspersed 

among the medullary cells and/or cortical cells. The cortex is 

of several rows of small, compacted pigmented cells, 2–15 μm 

in diameter, becoming smaller outward; in surface view cortical 

cells may be regularly or irregularly arranged. 

Life histories are triphasic. Fertile branches can be simple 

or pinnately compound, often with a sterile margin around the 

reproductive structures. Tetrasporangia are developed in sori, 

covering the somewhat expanded or broadly rounded tips of lateral branches, and the main axes’ branch tips. Tetrasporangia are 

tetrahedrally divided and embedded in the cortex. Carpogonial 

filament is unicellular and, after fertilization, fuses with adjacent 

cells. Carposporangia develop on both sides of fertile branch. 

Mature cystocarps are bilocular, with two ostioles, and protrude 

equally on both surfaces of the branch near apices. Spermatangia 

are in sori on branch surfaces.

Remarks. Large and small thalli of Gelidium are occasional to abundant in the intertidal habitats throughout the 

Gulf of California and are less common in the shallow subtidal. 

Some species are commercially important and utilized by industry 
306 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

as agar sources (Friedlander, 2007; Arvizu-Higuera et al., 2007). 

In Mexico companies such as Industrias Gel-Mex of Baja California have harvested species of Gelidium. Sulfated polysaccharides 

of Brazilian Gelidium crinale exhibited anticoagulant activity 

(Pereira et al., 2005). The chemical properties of the species in 

northern Gulf of California have not yet been investigated. 

There are two species reported in the southern Gulf: 

Gelidium coronadense E. Y. Dawson (1953a) is listed without 

comment from Bahía de Loreto (CONANP, 2002), and G. microdentatum E. Y. Dawson (1960a), described from San Blas, 

Nayarit (near the southern entrance to the Gulf of California), is 

a small, flat species with dentate margins occurring from Nayarit 

to Jalisco (Serviere-Zaragoza et al., 1993b; González-González 

et al., 1996).

Eight species of Gelidium are recognized in the northern 

Gulf of California.

KEY TO THE SPECIES OF GELIDIUM IN THE NORTHERN GULF OF CALIFORNIA

1a. One to several thalli in clumps; equal to or taller than 2 cm in height (some 5–15 cm tall) . . . . . . . . . . . . . . . . . . . . . . 2

1b. Thalli smaller, shorter, usually less than or sometimes up to 2 cm tall; in tufts, cushion-like or forming often extensive 

mats or smaller patches; sometimes within or entangled in algal turfs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2a. Erect, wiry thalli, 1.0–2.0(–3.5) cm tall; sparsely branched, axes and branches similar; terete (occasionally only slightly 

compressed), very slender, 125–225 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. crinale

2b. Erect thalli mostly (3–)5–15 cm tall; branches terete to flattened, much broader, over 600 μm in diameter (up to 3 mm in 

width) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Thalli 6–9 cm tall; axes subcylindrical, much branched irregularly, alternately to pinnately (2–4 orders); branches flattened, slender, 0.6–0.8(–1.5) mm in diameter, narrower in width at each order outward; ultimate branchlets most slender, 

of varying lengths, usually densely congested . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. decompositum

3b. Thalli 5–12 cm tall; flat throughout, mostly 1.5–3.0 mm wide; branching distichously, mostly opposite, regular, pinnate; 

ultimate branchlets of uniform size, 1–2 mm long, up to 0.5 mm wide (not markedly congested) . . . . . . . G. johnstonii

4a. Axes either terete to slightly compressed throughout or only partially in lower portions with upper portions flattened; 

mostly less than 600 μm wide (range, 200–700 μm wide); variably branched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4b. Axes of compressed to flat branches; broader, mostly over 600 μm wide (range, 600–900 μm wide) . . . . . . . . . . . . . . 6

5a. Thalli terete to only slightly compressed throughout; narrower, 150–250 μm in diameter, and thicker, 150 μm or more 

thick; subdichotomously to irregularly branched; tetrasporangial branchlets with acute apices . . . . . . . . G. refugiensis

5b. Thalli terete to compressed basally and markedly flat upper axes and branches; sparsely to more or less densely, pinnately 

to irregularly branched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6a. Thalli of slightly compressed to flattened branches, 200–650 μm wide, mostly less than 100 μm thick; simple or sparingly 

branched or sometimes branched pinnately; flat branches usually extended into long, slender, subcylindrical, flagellate 

extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. mcnabbianum

6b. Thalli compressed to flattened, broader, 600–900(–1200) wide, and thicker, greater than 150 (up to 350) μm thick; 

irregularly pinnately branched; branches without apical extensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. microphysa

7a. Branches 200–700 μm wide, mostly 100–120 μm thick; pinnately to irregularly branched; tetrasporangial sori without a 

thick sterile margin, on tetrasporangial branchlets with broad rounded apices . . . . . . . . . . . . . . . . . . . . . . G. pusillum

7b. Branches up to 1 mm wide; tetrasporangial sori with a thick sterile margin, on tetrasporangial branchlets with an indented apical margin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. sclerophyllum

Gelidium crinale (Hare ex Turner) Gaillon

FIGURE 150F,G

Fucus crinalis Hare ex Turner, 1819:4, pl. 198: figs. a–c, e–g (see Remarks 

below).

Gelidium crinale (Hare ex Turner) Gaillon, 1828:362; Okamura, 1915:195, 

pl. 14: figs. 1–10; Dawson, 1944a:259; Taylor, 1945:155; Dawson, 1953a:64, pl. 4: fig. 5; 1961b:408; 1966a:16; Dixon and Irvine, 

1977a:140; Santelices, 1977:67, fig. 2A–C; Stewart and Stewart, 

1984:142; Santelices and Stewart, 1985:22, fig. 11; Santelices, 1988:96, 

fig. 5; Rodríguez-Vargas and Santelices, 1988:117, tbls. 1, 2, fig. 5; 

Ramírez and Santelices, 1991:189; Rodríguez-Vargas et al., 1993:446; 

Serviere-Zaragoza et al., 1993a:483; Serviere-Zaragoza et al., 

1993b:48; H.-B. Lee, 1994:70, figs. 5–8; H.-B. Lee and Kim, 1995:164, 

fig. 5; Abbott, 1999:192, fig. 49A; L. Aguilar-Rosas et al., 2000:130; 

2002:234; Xia et al., 2002:187, figs. 7, 8, 78; Perrone et al., 2006:24, 

fig. 14; Mateo-Cid et al., 2006:55; Santelices, 2007:294, tbl. 1. 

Gelidiella mexicana sensu Dawson, 1944a:262 [in part; only Guaymas 

specimens; non Gelidiella mexicana E. Y. Dawson, 1944a:262, which is 

now Gelidiella hancockii E. Y. Dawson, 1944a:261—see also Dawson, 

1953a:64]. 

Algae erect, wiry tufts, 1.0–3.0(–3.5) cm tall; axes unbranched or sparsely irregularly branched, up to 2 orders; axes 

and branches thin, terete to only slightly compressed, 125–225 μm 

in diameter; arising from entangled, more or less terete, prostrate 

branches, attached by brush-like haptera directly to substratum 

or sometimes partially penetrating substratum. Transection with 

inner medulla of 1–2 or small group of rows of thick-walled cells; 

outer medulla of cells 6–15 μm in diameter; rhizoidal filaments 
NUMBER 96 • 307

among cells of medulla and subcortical regions. Cortex of 3–5 

layers of small cells, mostly 4–6 μm long, 6–8 μm in diameter.

Tetrasporangia in upper portions of simple, pinnate or 

digitate-shaped, terminal branchlets; tetrasporangia spherical, 

about 30 μm in diameter. Cystocarpic and spermatangial thalli 

not known in the northern Gulf. Cystocarps as reported elsewhere: ovoid, 500–600 μm in diameter, 500 μm thick (Santelices 

and Stewart, 1985).

Habitat. On exposed rocks and tidal platforms or 

sometimes in sand-covered substratum; intertidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to El Coloradito; Bahía San Luis Gonzága; 

Isla Turner (Islas de la Cintura); Mazatlán, Sinaloa to Jalisco.

Eastern Pacific: Isla Guadalupe; Bahía Magdalena, Baja California 

Sur; Colima to Oaxaca; Galápagos Islands; Chile. Central Pacific: 

Hawaiian Islands. Western Pacific: China; Korea; Japan; Vietnam.

Type Locality. Ilfracombe, Devonshire, England, 

UK (Lipkin and Silva, 2002).

Remarks. Although Gelidium crinale has been widely 

reported in distribution (Guiry and Guiry, 2008–2010), its species 

limits are not fully understood. In the northern Gulf G. crinale

is wiry, with slender, terete axes, and unbranched to sparsely, irregularly branched. The other small turf species of Gelidium in 

the Gulf are usually shorter: G. refugiensis, although similarly terete to slightly compressed, is subdichotomously branched with 

slightly wider branches, and G. pusillum and G. sclerophyllum

have flattened upper axes and branches and are pinnately to irregularly branched. Specimens of Gulf of California G. crinale need 

to be molecularly compared with G. crinale from other regions 

(Freshwater et al., 2002), particularly those of the type locality.

“Fucus crinalis Hare ex Turner” in volume 4 of Turner is 

usually cited as 1819, but the exact publication date is uncertain. 

Turner’s volumes were published in fascicles “possibly” from 

1811 to 1819 (Price, 1984:442), but the “details are lacking” 

(Stafleu and Cowan, 1986:346). More recently, Lipkin and Silva 

(2002:9) gave the date for F. crinalis as “1815,” but this has been 

queried by Guiry and Guiry (2010). Herein Turner (1819) is used 

for volume 4 until the exact date of publication can be resolved.

Gelidium decompositum Setchell et N. L. Gardner

FIGURE 151

Gelidium decompositum Setchell et N. L. Gardner, 1924:743, pl. 71; Dawson, 1944a:260; 1953a:67; Norris, 1973:9; González-González et al., 

1996:205, 392; CONANP, 2002:139. 

Pterocladia capillacea sensu Stewart and Norris, 1981:279 [in part; only 

northern Gulf of California specimens], fig. 5 [non Pterocladia capilFIGURE 150. Species of Gelidium. A, B. Gelidium mcnabbianum: Habits of specimens from the type collection (after Dawson, 1957c: figs. 4c, 

d). C. Gelidium microphysa: Habit of the type specimen (after Setchell and Gardner, 1930: pl. 9: fig. 31). D, E. Gelidium refugiensis: D. Tip 

of sporangial branch showing openings through cortex. E. Portion of type showing habit (D, E, after Dawson, 1944a: pl. 43, figs. 4, 5). F, G. 

Gelidium crinale: Habits of two Gulf specimens (F, JN-3310, US Alg. Coll.-159270; G. JN-3483, US Alg. Coll.-159274).
308 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

lacea (S. G. Gmelin) Bornet in Bornet et Thuret, 1876:57, which is now 

Pterocladiella capillacea (S. G. Gmelin) Santelices et Hommersand, 

1997:118].

Algae bushy, up to 9 cm tall; of 1 to a few erect, narrow, flattened main axes, (600–)750–800(–1500) μm wide and 160–370 

μm thick; attached to substratum by loose, creeping prostrate 

basal branches, sometime more or less penetrating substratum 

such as crustose corallines. Axes irregularly divided some distance above base into several primary branches, further irregularly dividing upward 2–3 times to form branches in a more 

or less alternately pinnate arrangement. Each different order of 

branches of variable lengths, nearly perpendicular to branch of 

origin, becoming successively more slender and remaining flattened; subultimate and ultimate branchlets often densely matted 

to each other. Transection showing rhizoidal filaments scattered 

through medulla of main axes but not observed in terminal or 

subterminal branchlets.

Reproduction not known. 

Habitat. On rocks and tidal platforms and in crevices and tide pools, sometimes growing on crustose coralline 

algae; mid intertidal to shallow subtidal, down to 4 m depths. 

Distribution. Gulf of California: Puerto Calamajué to Bahía San Francisquito; Isla Partida and Isla Rasa (Isla 

Raza; southwestern Islas de la Cintura); Bahía de Loreto. 

Type Locality. Bahía San Francisquito, Baja California, Gulf of California, Mexico.

Remarks. Gelidium decompositum is apparently 

restricted to a rather narrow distribution on the central Baja 

California coast of the northwestern Gulf of California and two 

of the Islas de la Cintura (Midriff Islands). Dawson (1953a, 

1959a) commented that Gelidium decompositum was almost the 

same as Pterocladia pyramidale (N. L. Gardner) E. Y. Dawson 

(1945e), and later, he suggested that G. decompositum might belong in Pterocladia (Dawson, 1961b). Reexamination of northern Gulf specimens suggests that there may be two taxa, and for 

now Gelidium decompositum sensu Setchell and Gardner (1924) 

is tentatively recognized as being separate from northern Gulf 

Pterocladiella capillacea.

However, this needs further study, as Dawson (1959a) noted 

the tropical-subtropical eastern Pacific specimens identified as 

“Pterocladia pyramidale” from Rocas Alijos, Isla Clarión (Islas 

Revillagigedo), and the Galápagos Islands may also belong in G. 

decompositum. The generic placement and taxonomic status of 

Gelidium decompositum needs to be confirmed by the finding of 

cystocarpic specimens and comparative molecular and phylogenetic analyses to elucidate its relationship to Pterocladia pyramidale and Pterocladiella capillacea.

Gelidium johnstonii Setchell et N. L. Gardner

FIGURE 152

Gelidium johnstonii Setchell et N. L. Gardner, 1924:742, pl. 46: fig. A, pls. 

72, 73 [type specimen]; Dawson, 1944a:260; 1953a:73; 1959a:20; 

1961b:408; 1966a:16; Norris, 1973:9; Huerta-Múzquiz, 1978:336, 

337; Littler and Littler, 1981:151; Stewart and Norris, 1981:274, 

tbl. 1, 277; Mendoza-González and Mateo-Cid, 1985:28; Santelices and Stewart, 1985:26, fig. 25; Mendoza-González and MateoCid, 1986:422; Mateo-Cid et al., 1993:47; Serviere-Zaragoza et al., 

1993b:48; González-González et al., 1996:206; Mateo-Cid et al., 

2000:64; L. Aguilar-Rosas et al., 2000:130; CONANP, 2002:139; 

Pacheco-Ruíz and Zertuche-González, 2002:467; Pacheco-Ruíz and 

Zertuche-González, 2002:467; R. Aguilar-Rosas et al., 2005:32; 

Mateo-Cid et al., 2006:55. 

Algae of several, erect, narrow, distinctly flattened axes, 

up to 12 cm high, 1.0–1.5 mm wide (more narrow near bases 

and apices), repeatedly pinnately branched in 1 plane; ultimate 

branchlets more or less uniform in length; arising from a holdfast 

of branched stolons. Rhizoidal filaments interlaced in medulla 

and sometimes in subcortex; usually abundant, but sometimes 

varying in abundance in young and mature parts of thalli.

Tetrasporangia in sori of various sizes and shapes on ultimate branchlets. Cystocarps, often inconspicuous, borne distally 

on branch apices. Spermatangia unknown. 

Habitat. On rocks, usually in semiprotected, shaded 

areas and in crevices and tide pools; low intertidal to shallow 

subtidal, down to 6 m depths. 

Distribution. Gulf of California: Puerto Peñasco 

to Bahía Agua Verde; Puerto Refugio, Isla Ángel de la Guarda; 

Caleta Partida (in shallow channel between Isla Partida and Isla 

Espíritu Santo) to Cabo Pulmo. Eastern Pacific: Punta Santa Rosaliita (“Punta Santa Rosalía”), Baja California to Bahía Magdalena, Baja California Sur. 

FIGURE 151. Gelidium decompositum: Habit, some portions of 

thalli are dense and congested (JN-4611, US Alg. Coll.-159296). 
NUMBER 96 • 309

Type Locality. Bahía San Francisquito, Baja California, Gulf of California, Mexico.

Remarks. Gelidium johnstonii can be distinguished 

from other species of Gelidiaceae in the northern Gulf by its 

larger size, notably flattened axes, more regular pinnate habit, 

and ultimate branchlets of similar length.

Western Pacific records of G. johnstonii need to be verified. For example, Yoshida (1998) referred “G. johnstonii” as 

identified in Japan by Segi (1955) to G. elegans Kützing (1868), 

and H.-B. Lee and Kim (1995) considered “G. johnstonii” as 

reported in Korea (Sohn and Kang, 1978) to be a variant of G. 

amansii (J. V. Lamouroux) J. V. Lamouroux (1813). Reports of 

“G. johnstonii” from Guangdong Province, Hong Kong, and 

Taiwan (Tseng et al., 1980; Zhang and Xia, 1988) were later 

recognized to be G. tsengii K.-C. Fan (1961) by Xia et al. (2002).

Gelidium mcnabbianum (E. Y. Dawson) Santelices

FIGURES 150A,B, 153A,B 

Pterocladia mcnabbiana E. Y. Dawson, 1957c:14, fig. 4C,D; 1961c:409, 

pl. 2: figs. 5–6; 1966a:16; 1966b:59; Stewart and Norris, 1981:274, 

tbl. 1; Ramírez and Santelices, 1991:195; González-González et al., 

1996:262; Mateo-Cid et al., 2006:51; Bernecker, 2009:CD-Rom p. 60; 

Fernández-García et al., 2011:64. 

Gelidium mcnabbianum (E. Y. Dawson) Santelices, 1998:245; Santelices, 

1999:74; López et al. 2004:11.

Algae of several erect or decumbent, terete to partly flattened, branched axes, up to 2 cm tall, up to 650 μm wide; axes 

simple or sparingly branched, sometimes branched pinnately; 

arising from prostrate subcylindrical, much branched attachment stolons, up to 100 μm in diameter. Upper portions of some 

branches sometimes becoming narrower, elongated, and attenuated (flagellate), sometimes as long subcylindrical extensions 

(Figure 153A). Internally, rhizoidal filaments scattered through 

medulla, varying in abundance.

Tetrasporangia in sori on flat, elliptical branches. Cystocarps bilocular, ostiolate, and embedded on branch apices. Spermatangial thalli unknown.

Habitat. in algal mats on rocks, and shells; intertidal 

to shallow subtidal. 

Distribution. Gulf of California: Puerto Peñasco. 

Eastern Pacific: Guerrero; El Salvador; Costa Rica; northern 

Peru.

Type Locality. Small mats on hull of shipwreck; 

Bahía Golfito, SW of Golfo Dulce, Pacific Costa Rica.

Remarks. Santelices (1998), in studying the type material of Pterocladia mcnabbiana, found the internal structure to 

FIGURE 152. Gelidium johnstonii: A. Habit of female gametophyte with holdfast (arrow) (JN-5539, US Alg. Coll.-159337). B. Habit of tetrasporophyte (JN-3796, US Alg. Coll.-159339).
310 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

be that of the Gelidium. Earlier, Dawson (1957c) contrasted the 

type specimen of Pterocladia mcnabbiana with other small species of Gelidium and Pterocladia and noted it to differ in having 

a mixture of both terete and flattened erect branches and prominent flagellate terminal extensions on some of the branches. Gulf 

of California Geldium mcnabbianum and the other small species of the Gelidium–Pterocladia complex are in need of critical 

study, after fertile material has been found for each and compared to type locality G. mcnabbianum. 

Gelidium microphysa Setchell et N. L. Gardner

FIGURE 150C

Gelidium microphysa Setchell et N. L. Gardner, 1930:151, pl. 9: fig. 31; 

Dawson, 1944a:260; 1953a:61; 1961b:409; 1966a:16; GonzálezGonzález et al., 1996:206; Mateo-Cid et al., 2006:50. 

Algae erect, forming short, spreading mats, 0.6–1.5 cm tall; 

axes irregularly pinnately or flabellately branched, compressed 

to flattened throughout; short branches, 600–900(–1200) μm 

wide; branch apices usually rounded, with an apical cell within a 

slight to notable notch; uprights arising from creeping, prostrate 

axes attached below by short, peg-like holdfasts. Transection, a 

broad medulla, abundant internal rhizoidal filaments more or 

less evenly distributed in medulla and subcortex; cortex of small 

spherical cells, outer cortical cells very small, 3–5 μm in diameter. 

Tetrasporophytes unknown. Cystocarps 350–550 μm in 

diameter; usually 1, sometimes 2, on branchlets of compound, 

generally narrower, fertile branches. Spermatangia unknown. 

Habitat. On rocks and tidal platforms or along 

upper edges of tide pools; mid to low intertidal.

Distribution. Gulf of California: Bahía La Choya 

(Bahía Cholla), vicinity of Puerto Peñasco; Isla Patos (off N end 

of Isla Tiburón); Isla Turner (off SE end of Isla Tiburón); Isla 

Partida; Bahía de Los Ángeles. Eastern Pacific: Isla Guadalupe; 

Isla Cedros (both off Baja California).

Type Locality. Growing on rocks; Bahía Sur 

(South Bay), Isla Guadalupe, off Baja California, Pacific Mexico.

Remarks. Gelidium microphysa is a not well known 

in the northern Gulf. The only cystocarp specimen is from Isla Partida. More collections, particularly from the Pacific Mexico type locality, Isla Guadalupe, are needed for morphological and molecular 

comparisons with the northern Gulf specimens referred to G. microphysa. Dawson (1953a) also noted several tubercular nodules 

on Isla Partida G. microphysa that might be parasitic red algae, but 

none were reproductive and their identity remains undetermined.

Gelidium pusillum (Stackhouse) Le Jolis

FIGURES 153C, 154

Fucus pusillus Stackhouse, 1795:16, pl. 6. 

Gelidium pusillum (Stackhouse) Le Jolis, 1863b:139; Okamura, 1909:11, 

pl. 54: figs. 10–14; 1934b:38, pl. 17: figs. 1, 2, pl. 31: figs. 1, 2; Dawson, 1944a:258, pl. 42: figs. 1–6; Taylor, 1945:152; Dawson, 1953a:62; 

1959a:20; 1961c:408, pl. 10: figs. 1–2, 5; 1966a:16; Huerta-Múzquiz 

and Tirado-Lizárraga, 1970:127; Norris, 1973:9; Chávez-Barrear, 

1972b:268; Huerta-Múzquiz and Garza-Barrientos, 1975:8; Stewart, 

1976:347, fig. 290; Huerta-Múzquiz, 1978:338; Stewart and Norris, 

1981:274, tbl. 1, 275; Littler and Littler, 1981:148, 150–151; Littler and 

Arnold, 1982:309; Schnetter and Bula-Meyer, 1982:116, pl. 13: figs. 

A–E, H, I, pl. 14: figs. A–D; Pacheco-Ruíz and Aguilar-Rosas, 1984:71, 

FIGURE 153. Species of Gelidium. A, B. Gelidium mcnabbianum: Habits (EYD-27340, US Alg. Coll.-40743). C. Gelidium pusillum: Habit 

(JN-3482, US Alg. Coll.-159272).
NUMBER 96 • 311

76; Stewart and Stewart, 1984:142; Santelices and Stewart, 1985:22, 

fig. 9; Huerta-Múzquiz and Mendoza-González, 1985:48; MendozaGonzález and Mateo-Cid, 1985:28; Mendoza-González and MateoCid, 1986:422; Santelices, 1988:102, fig. 9; Dreckmann et al., 1990:27, 

pl. 4: fig. 5; Ramírez and Santelices, 1991:192; Stewart, 1991:70; 

Mateo-Cid and Mendoza-González, 1992:19; Mendoza-González 

and Mateo-Cid, 1992:16; Rodríguez-Vargas et al., 1993:447; LeónTejera et al., 1993:200; Serviere-Zaragoza et al., 1993a:483; ServiereZaragoza et al., 1993b:48; Mateo-Cid et al., 1993:47; Mateo-Cid and 

Mendoza-González, 1994b:38; R. Aguilar-Rosas and Aguilar-Rosas, 

1994:520; Mendoza-González et al., 1994:105; Womersley and Guiry, 

1994:133, figs. 35E, 39E–K; González-González et al., 1996:312; Athanasiadis, 1996b:85; Abbott, 1999:194: fig. 50A; Yoshida, 1998:637; 

León-Tejera and González-González, 2000:327; Mateo-Cid et al., 

2000:64; CONANP, 2002:139; L. Aguilar-Rosas et al., 2002:234; 

Pacheco-Ruíz and Zertuche-González, 2002:467; Mateo-Cid et al., 

2006:50, 55; Perrone et al., 2006:24, 28, figs. 4, 38; Serviere-Zaragoza 

et al., 2007:10; Santelices, 2007:294, tbl. 1; Bernecker, 2009:CD-Rom 

p. 60; Fernández-García et al., 2011:62.

Gelidium crinale var. crinale sensu Dawson, 1944a:259; 1953a:64 [non 

Gelidium crinale (Hare ex Turner) Gaillon, 1828:362]. 

Algae clumps or spreading turfs, 0.3–1.0(–2.0) cm tall; 

arising from peg-like or disc-like structures (brush-like haptera). Axes and branches compressed to flattened; main axes 

(0.5–)1.0–1.5(–2.0) mm wide, 100–300 μm thick; axes may be 

terete below but flattened above. Branching generally distichous, 

along margins and mostly irregular; branches flat, lanceolate to 

spatulate, usually with blunt apices. Rhizoidal filaments few to 

abundant, scattered or congested. Medullary cells up to 10 μm in 

diameter; rhizoidal filaments abundant in inner medulla. Cortex 

of 2–3 layers of small cortical cells, mostly 4–6 μm in diameter.

Reproductive structures on ovoid to rounded branchlets. 

Tetrasporangial sori generally oval, central on apical portions of 

branchlets, bordered by sterile margin; tetraspores ovoid, 25–35 

μm in diameter. Bilocular cystocarps round to ovoid, mostly 

600 μm in diameter, 500 μm thick. Spermatangia not seen in 

Gulf specimens. 

Habitat. Often common on rocks and mollusk 

shells; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Cabo Pulmo; Mazatlán, Sinaloa to 

Jalisco. Eastern Pacific: San Clemente Island (California Channel 

 FIGURE 154. Morphological variation in habits of Gelidium pusillum throughout its range: A, C. Habits (from Pacific Costa Rica). B. Depauperate form. D. Broad blade form (B, D, from Isla Clarión, Islas Revillagigedo; after Dawson, 1953a). E. Habit (from the Gulf of California) 

(A–E, after Dawson, 1944a: pl. 42: figs. 1–5).
312 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Islands) to Playa Los Cerritos (vicinity of Todos Santos), Baja 

California Sur; Isla Socorro and Isla San Benedicto (Islas Revillagigedo); Colima to Oaxaca; El Salvador; Costa Rica; Panama; 

Colombia to Chile; Rapa Nui (Easter Island; Isla de Pascua). 

Central Pacific: Hawaiian Islands. Western Pacific: China; Taiwan; Japan; Korea; Vietnam.

Type Locality. Sidmouth, Devon, England, United 

Kingdom (Dixon and Irvine, 1977a). 

Gelidium refugiensis (E. Y. Dawson) Santelices

FIGURE 150D,E

Gelidiella? refugiensis E. Y. Dawson, 1944a:262 [with a generic query], pl. 

43: figs. 4–6; 1953a:84; 1961b:410; Stewart and Norris, 1981:274, tbl. 

1; González-González et al., 1996:204; Santelices, 2007:295, tbls. 2, 3.

Gelidium refugiensis (E. Y. Dawson) Santelices, 2007:298, figs. 11–13.

Algae of small, subcylindrical to compressed erect axes, up 

to 1.5 cm tall, 150–250(–300) μm in diameter, loosely, subdichotomously to irregularly branched, mostly in 1 plane; apices rounded or sometimes acute; basal portion not completely 

known, probably attached by small, brush-like haptera. Medulla 

of 3–4 rows of medullary cells; internal rhizoidal filaments more 

frequent in medulla than in cortex and in lower portions of erect 

axes than in upper portions. Cortex of 3–4 layers of small, pigmented cortical cells.

Reproduction by large undivided spores (monospores), 

20–40(–50) μm in diameter; borne in terminal branchlets; 

monospores leave openings in cortex after being discharged. 

Cystocarpic and spermatangial thalli unknown. 

Habitat. Unknown; type and only specimens collected to date are from drift. 

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda; Bahía San Carlos. 

Type Locality. In beach drift on north shore; 

Puerto Refugio, Isla Ángel de la Guarda (Islas de la Cintura), 

Gulf of California, Mexico. 

Remarks. This taxon was originally placed in Gelidiella by Dawson (1944a) with a generic query. Its generic status 

remained uncertain until it was clarified by Santelices (2007) and 

recognized as Gelidium refugiensis. 

Gelidium sclerophyllum W. R. Taylor

Gelidium sclerophyllum W. R. Taylor, 1945:156, pl. 5: fig. 13, pl. 33: fig. 

2; Dawson, 1953a:63; 1957c:14; 1961b:409; 1961c:409, pl. 10: fig.7; 

1962c:229; Dreckmann et al., 1990:27; Mateo-Cid et al., 1993:47; 

Rodríguez-Vargas et al., 1993:447; Serviere-Zaragoza et al., 1993b:48; 

González-González et al., 1996:208; Mateo-Cid et al., 2000:64; Tejada, 2003:11; Bernecker, 2009:CD-Rom p. 60; Fernández-García et 

al., 2011:62.

Algae of small, more or less dense tufts, up to 2.0 cm tall; 

of numerous erect, flattened fronds arising from creeping, prostrate branched axes attached to substratum by peg-like haptera. 

Erect axes terete to compressed at base; ligulate above, up to 

1 mm wide; branching sparse to irregularly pinnate, with 1 to 

several lateral branchlets. Branchlets constricted at base; apices 

of fertile branchlets usually deeply indented. Medulla dense with 

thick-walled cells, surrounded by closely packed rhizoidal cells, 

which become scattered in the subcortex.

Tetrasporangial sori depressed in central region of lateral 

and terminal branchlets, with thicker sterile margins. Cystocarps 

400–500 μm in diameter; borne near ends of lateral and terminal 

branchlets. Spermatangia not known.

Habitat. Growing on crustose corallines, barnacles, 

and attached mollusks; intertidal.

Distribution. Gulf of California: Isla Pelícanos, 

Bahía Kino; Bahía Concepción to Cabeza Ballena; Mazatlan, 

Sinaloa to Jalisco. Eastern Pacific: Isla Clarión (Islas Revillagigedo); Baja California Sur; Colima to Oaxaca; El Salvador; 

Nicaragua; Costa Rica; Ecuador.

Type Locality. Dredged from 5.4 m depth; near 

northeast side of Ensenada de San Francisco, Provincia de Esmeraldas, northern Ecuador. 

Remarks. The small, flat Gelidium sclerophyllum is 

distinguished by its branchlets constricted at their base, dense medulla of thick-walled cells and tetrasporangial sori with thicker, 

sterile margins, on tetrasporangial branchlets with indented tips.

Uncertain Record:

Gelidium coulteri Harvey

Gelidium coulteri Harvey, 1853:117; Smith, 1944:196, pl. 44: fig. 5; 

Dawson, 1953a:70; Stewart, 1976:344, fig. 287; Rodríguez-Vargas 

and Santelices, 1988:115, tbls. 1, 2, figs. 3, 5; Stewart, 1991:69; 

Serviere-Zaragoza et al., 1993b:48; González-González et al., 

1996:205.

Remarks. Recorded from Segundo Cerro Prieto, 

Bahía Kino, by Mendoza-González and Mateo-Cid (1986); further collections will be helpful to verify its presence in the northern Gulf of California. 

Gelidiellaceae

Gelidiellaceae K.-C. Fan, 1961:317; Norris, 1992b:159; Perrone et al., 

2006:31 [emended description].

Algae are composed of erect and prostrate axes. Uprights 

are terete to flattened and sparsely, irregularly or pinnately 

branched. In some the main stolon represents the main axis. 

Growth is uniaxial, with the apical cell dividing distichously or 

decussately. Internally, the thallus anatomy is completely without the thick-walled, refractive, unicellular rhizoidal filaments 

(rhizines or hyphae) that are characteristic of the Gelidiaceae 

and Pterocladiaceae. The creeping, prostrate axes are attached 

to the substratum only by single-celled, thick-walled, refractive rhizoidal filaments produced from the surface cells of the 

prostrate axes that remain in open connection with their parent 

cortical cells. 

Life histories are not fully understood. Tetrasporangial and 

spermatangial thalli are isomorphic, but cystocarpic thalli remain unknown. Tetrasporangia are tetrahedrally or decussately 

divided and are arranged irregularly in transverse parallel rows 

or in chevron-like rows, within tetrasporangial sori in conical 

or compressed apical regions of main axes and lateral branches. 
NUMBER 96 • 313

Female reproductive system is unknown. Spermatangia develop 

in raised spermatangial sori or form colorless patches in upper 

portions of the main axes and/or lateral branchlets.

Remarks. Currently there are two genera in the 

Gelidiellaceae. One of these, Parviphycus Santelices (2004) is 

known from Isla San Benedicto (Islas Revillagigedo) with the 

report of P. adnata (E. Y. Dawson) Santelices, 2004; ServiereZaragoza et al., 2007; basionym: Gelidiella adnata E. Y. Dawson, 1954b; Dawson, 1954a; Schnetter and Bula-Meyer, 1982; 

Santelices, 2002).

In the northern Gulf of California the Gelidiellaceae is represented by Gelidiella.

Gelidiella J. Feldmann et G. Hamel 

Gelidiella J. Feldmann et G. Hamel, 1934:529, nom. nov.

Echinocaulon Kützing, 1843:405 [non Echinocaulon (Meisner) Spach, 

1841:521; basionym: Polygonum sect. Echinocaulon Meisner, 

1832:58].

Algae composed of a few to several entangled, terete to 

slightly compressed, erect to decumbent branched axes, mostly 

up to 5 cm tall, with creeping, prostrate axes. Uprights are 

sparsely to abundantly, irregular branched and arise from very 

similar prostrate axes that attach to the substratum by single-cell 

rhizoids. Branches sometimes gradually tapered toward the apices and may be with sparse, filiform, distichously arranged, opposite or subopposite laterals. A single apical cell is evident at 

the branch apices. The cortex and medulla are similar in most 

respects to the other gelidiaceous algae, but differ in the notable 

lack of internal rhizoidal filaments (hyphae, rhizines), which are 

not found in any part of the thallus. In surface view the outer 

cortical cells may or may not be arranged in longitudinal rows. 

In transection the outer cortical cells are generally anticlinally 

elongated, gradually increasing in size inward. Medulla is composed of larger, colorless cells.

Tetrasporangial sori are in upper portion of lateral branchlets, usually swollen conical shape. Tetrasporangia are irregularly or regularly arranged in the sori, oblong, and tetrahedrally 

or irregularly cruciately divided. Those in lower portion of the 

sori are usually in a more advanced stage of development than 

those near the apex. Carposporophytes are unknown in the 

genus. Spermatangial sori are slightly elevated, 75–150 μm in 

diameter, with a raised, thick cuticle. Spermatia, 7–10 μm by 5–7 

μm, are cut off by transverse divisions of spermatangial parent 

cells in rows of up to 5 (spermatangia description after Santelices 

and Flores, 2004; based on G. acerosa from Haiti).

Gelidiella is represented by two species in the Gulf of 

California.

KEY TO THE SPECIES OF GELIDIELLA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli up to 5.0 cm tall; branches cylindrical to compressed, up to 1.0 mm in diameter . . . . . . . . . . . . . . . . G. acerosa

1b. Thalli shorter, mostly 1.0–1.5 cm tall; branches cylindrical throughout, much narrower, 100–120 μm in diameter . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. hancockii

Gelidiella acerosa (Forsskål) Feldmann et G. Hamel

Fucus acerosus Forsskål, 1775:190. 

Gelidiella acerosa (Forsskål) Feldmann et G. Hamel, 1934:533; Dawson, 

1944a:261; 1953a:82; 1961b:410; Huerta-Múzquiz and GarzaBarrientos, 1975:8, 11; Santelices, 1977:63, fig. 1A–C; HuertaMúzquiz and Mendoza-González, 1985:48; Santelices and Stewart, 

1985:21, fig. 6; Lewis and Norris, 1987:17; Santelices, 1988:93, figs. 

1; Mateo-Cid and Mendoza-González, 1991:20; Ramírez and Santelices, 1991:188; Norris, 1992b:154, figs. 4, 5; Melo, 1992:173, figs. 

1–8; Serviere-Zaragoza et al., 1993a:484; González-González et al., 

1996:312, 391; Anaya-Reyna and Riosmena-Rodríguez, 1996:864, 

tbl. 1; Santelices, 1997:77, figs. 1–14; Abbott, 1999:202, figs. 53A–C; 

Mateo-Cid et al., 2000:64; Cruz-Ayala et al., 2001:191; Santelices and 

Flores, 2004:109, figs. 1–11; Serviere-Zaragoza et al., 2007:10; Lin and 

Freshwater, 2008:172, figs. 13–19; Fernández-García et al., 2011:61.

Echinocaulon acerosum (Forsskål) Børgesen, 1932b:5, pl. 1; fig. 3 [type illustration of Fucus acerosus Forsskål, 1775].

Algae in tufts or clumps of usually entangled, narrow, cylindrical to slightly compressed, determinate erect or semierect to 

arching axes, up to 5 cm tall, mostly (550–)600–800 μm in diameter, with 1–2 orders of pinnate branchlets; uprights arising from 

creeping, prostrate, indeterminate stoloniferous axes, 500–600 

μm in diameter. Growth from a single apical cell. Medulla of 

large longitudinally elongated colorless cells, about 25–35 μm in 

diameter; grading into rounded, inner cortical cells. Outer cortex 

of 3–4 layers of small, ovoid to slightly elongated, pigmented 

cells, up to 7–8 μm long, (4–)5–7 μm in diameter. Rhizoidal filaments (rhizines) absent.

Tetrasporangia tetrahedrally or sometimes more or less cruciately divided, 40–50 μm long, 20–30 μm in diameter; developed from inner cortical cells; in 1–3 sori, each about 1 mm long 

and to 500 μm wide near distal end of lateral, comparatively 

swollen, branchlets. Gametangial thalli not known in Gulf of 

California. 

Habitat. On rocks or crustose corallines and in tide 

pools, sometimes in or around sand and pebbles; intertidal to 

about 1 m depths.

Distribution. Gulf of California: El Coloradito to 

Santa Teresa; Bahía Gabriel, Isla Espíritu Santo, and Bahía de 

La Paz to Cabeza Ballena; Nayarit to Jalisco. Eastern Pacific: 

Isla Guadalupe; Baja California; Colima to Guerreo; Isla Socorro and Isla Clarión (Islas Revillagigedo); Central America; 

Chile. Central Pacific: Hawaiian Islands; Guam. Western Pacific: 

China; Taiwan; Japan; Vietnam.

Type Locality. “Ad Mochhae littoral” (Forsskål, 

1775:190); Al Mukha, Red Sea, Yemen.

Remarks. Gelidiella acerosa has generally been accepted as being a geographically widespread species throughout 
314 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

tropical to warm temperate seas. In China G.acerosa is an economically important seaweed that is harvested in Hainan Province, notably on Hainan Island and the Xisha (Paracel) Islands 

(Tseng, 1983). 

Santelices and Flores (2004), finding differences between 

specimens of “G. acerosa” from the Caribbean and Pacific, suggested they may be two separate taxa. In another study, molecular sequences of specimens identified as “G. acerosa” from the 

Caribbean, southeastern Australia, and the Indo-Pacific were 

found to be separate species from each other, and one from Taiwan was described as a new, Gelidiella fanii S.-M. Lin (in Lin 

and Freshwater, 2008). Future morphological and molecular 

comparisons will elucidate the taxonomic status of Gulf of California specimens referred to G. acerosa and their relationship to 

those of other geographical areas, particularly those of the type 

locality in the Red Sea, Yemen.

Gelidiella hancockii E. Y. Dawson 

FIGURE 155A

Gelidiella hancockii E. Y. Dawson, 1944a:261, pl. 43: figs. 1, 2; 1953a:83, 

pl. 12: figs. 6–7; 1959a:20; 1960a:37; Huerta-Múzquiz and TiradoLizárraga, 1970:127; Stewart and Norris, 1981:274, tbl. 1; HuertaMúzquiz and Mendoza-González, 1985:48; Mendoza-González and 

Mateo-Cid, 1985:28; Mendoza-González and Mateo-Cid, 1986:422; 

Ortega et al., 1987:71, pl. 2: figs. 9–12; León-Tejera et al., 1993:200; 

González-González et al., 1996:203; Silva et al., 1996b:232; L. AguilarRosas et al., 2000:130; Santelices, 2007:298, tbls. 2, 3; Bernecker, 

2009:CD-Rom p. 60; Fernández-García et al., 2011:61. 

Gelidiella mexicana E. Y. Dawson, 1944a:262 [in part; excluding Guaymas 

specimens], pl. 43: fig. 3; Santelices, 2007:295, tbl. 2. 

Algae of densely entangled tufts, up to 2 cm high; erect axes 

cylindrical throughout, 120–200 μm in diameter, irregularly 

branched; arising from prostrate, mostly unbranched axes (only 

occasionally secondarily branched) attached by unicellular rhizoids to substratum; apices acute, not attenuated. Internally of 

compacted colorless medullary cells and pigmented cortical cells 

of similar diameter; lacking internal rhizoidal filaments.

Tetrasporangia borne in short branchlets or on branch apices. Cystocarpic and spermatangial thalli unknown. 

Habitat. On rocks, sometimes entangled among 

other turf algae; intertidal. 

Distribution. Gulf of California: El Coloradito to 

Bahía San Luis Gonzága; Puerto Refugio, Isla Ángel de la Guarda, 

Isla Tiburón, and Isla Estanque (Isla Pond) (Islas de la Cintura); 

Bahía Kino; Laguna Agiabampo; La Paz; Nayarit. Eastern Pacific: 

Isla Margarita, Bahía Magdalena, Baja California Sur; Rocas Alijos; Golfo de Tehuantepec, Oaxaca; Costa Rica; Panama.

Type Locality. On mid intertidal rocks; rocky 

point, about 4.8 km (3 miles) north of Bahía Kino, Sonora, Gulf 

of California, Mexico.

Remarks. Gelidiella hancockii and another small 

species, G. mexicana, were both described by Dawson (1944a) 

from the northern Gulf. Gelidiella mexicana (type locality: Isla 

Estanque, off the southeast end of Isla Ángela de la Guarda) was 

later considered to be conspecific with G. hancockii (Dawson, 

1953a). Santelices (2007) studied the types of each species and 

found them to lack internal rhizoids and to be attached by externally produced, single-celled rhizoids, characters that supported 

their placement in Gelidiella.

Pterocladiaceae

Pterocladiaceae Felicini et Perrone in Perrone, Felicini, et Bottalico, 2006:31.

Algae consisting of narrow, compressed to flattened, erect 

uprights that are sparsely to pinnately branched and always develop opposite the attachment haptera of the lower prostrate, 

terete to compressed stolon-like axes. The prostrate system is 

composed of irregularly branched, prostrate axes that bear complex, peg-like haptera that either adhere directly to the substratum or penetrate it, producing a circular hole. These attachment 

structures consist of two kinds of filaments: thick-walled, refractive, unicellular, colorless rhizoidal filaments that originate from 

inner cortical cells and grow through the thallus, protruding between the surface cells and coalescing in a thick sheath, and pigmented, multicellular, uniseriate filaments that develop from the 

surface cells and form a basal cortication around the hapteron 

base. Growth is uniaxial. Internally, thick-walled, refractive, 

unicellular rhizoidal filaments (rhizines or hyphae) develop from 

the inner cortical cells and grow basipetally through the thallus; 

these vary in abundance and distribution within the medulla and 

cortex and may be numerous or sometimes not present. 

Life histories, where known, are triphasic, of isomorphic 

tetrasporophytes and gametophytes. Tetrasporangia are in apical sori, arranged irregularly or in rows meeting at an angle 

(chevron-like). Gametangial thalli may be dioecious or monoecious. Cystocarps are unilocular, usually with 1 ostiole, and 

FIGURE 155. Species of Gelidiella and Pterocladiella. A. Gelidiella 

hancockii: Habit (after Dawson, 1944a: pl. 43: fig. 1). B. Pterocladiella caloglossoides: A small, suberect branch from the type collection

(after Dawson, 1953a: pl. 6: fig. 2, as Pterocladia parva). 
NUMBER 96 • 315

protrude on either or both sides of reproductive branches. Spermatangia are in sori on the branch surfaces.Two genera of Pterocladiaceae are known in the northern 

Gulf of California.

KEY TO THE GENERA OF PTEROCLADIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Unilocular cystocarps with 1 ostiole; placental tissue only on floor of cystocarp cavity . . . . . . . . . . . . . . . . Pterocladia

1b. Unilocular cystocarps usually with 1 ostiole (rarely with 2); placental tissue surrounding central axis . . . . . Pterocladiella

Pterocladia J. Agardh

Pterocladia J. Agardh, 1852a:482.

Algae are tufts or clumps or may occur in mats of algal turf, 

2.0–40 cm tall, and composed of one to several cartilaginous, 

terete or compressed, erect narrow axes that are mostly irregularly branched. The upright axes are cylindrical at their base 

and become subcylindrical to compressed above and arise from 

cylindrical or compressed, branched or unbranched, creeping, 

prostrate axes that attach to the substratum by numerous short 

peg-like haptera. In surface view the cortical cells may or may 

not be arranged in longitudinal series. In transection, the cortex 

is often of several rows of pigmented cells, mostly 2.0–15 μm in 

diameter, the smaller usually toward the outside. Medullary cells 

are generally rounded, up to 30 μm in diameter, colorless, compacted or loosely appressed. Rhizoidal filaments (also called rhizines or hyphae) among the medullary and/or cortical tissue are 

elongated, thick-walled, colorless cells, up to 5 μm in diameter, 

and often vary in number and position within a given species. 

The tetraspores in the sori occupy the entire, somewhat expanded or broadly rounded tips of lateral branches or main axes. 

Sporophylls can be single or pinnately compound. Tetrasporangia are cruciately divided, up to 35 μm in diameter, and are generally arranged without order in the sori, although a few species 

may exhibit tetrasporangia borne in regular V-shaped rows. The 

mature cystocarps are unilocular, protruding on only one of the 

surfaces of the branches, usually with one or more openings 

on only one surface of the frond. Carposporangia are usually 

formed in short chains. Spermatangial sori are sometimes apparent as relatively unpigmented areas on the apices of branchlets. 

Remarks. Pterocladia species can often be similar to 

species of Gelidium and Pterocladiella, both in morphology and 

anatomy (see discussion of Gelidium). The axes of Pterocladia

are generally flattened in both erect and prostrate parts, rather 

than being partly terete or compressed, and thalli are often not as 

rigid as most Gelidium specimens. Rhizoidal filaments in some 

species of Pterocladia tend to be more central in the medulla, but 

this in itself does not separate species of the genera. 

The position of the reproductive structures is also the same 

in these genera. Tetrasporangia are borne in sori on ultimate 

branches. The unilocular cystocarps are the only positive diagnostic character for Pterocladia species. These bulge prominently 

on one side of the upper branches. Spermatangia are superficial 

in sori near branch apices. The only positive way to separate 

Pterocladia, Pterocladiella, and Gelidium is by examining the 

attachment structures of carpogonial thalli. The cystocarps 

are unilocular, protruding and opening on only one side of the 

branch in Pterocladia, and bilocular, protruding and opening on 

both sides of the branch in Gelidium. 

There are two species of Pterocladia in the Gulf of California.

KEY TO THE SPECIES OF PTEROCLADIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli mostly up to 2 cm tall, branching sparse; flat axes 150–300 μm wide, and thin, 100–200 μm thick. . . . P. media

1b. Thalli up to 6 cm tall, branching widely irregular; flat axes broader, 900–1100 μm wide, and usually thicker, 180–230 μm 

thick. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. sonorense

Pterocladia media E. Y. Dawson

Pterocladia media E. Y. Dawson, 1958:68, pl. 21: figs. 3, 4, pl. 24: fig. 11; 

1961b:410; Stewart, 1974b:105, fig. 1; 1976:351, fig. 294; Stewart 

and Norris, 1981:277; Pacheco-Ruíz and Aguilar-Rosas, 1984:76; 

Ramírez and Santelices, 1991:195; Stewart, 1991:73; 1992:184, fig. 5; 

Mendoza-González and Mateo-Cid, 1992:16; Rodríguez-Vargas et al., 

1993:448; Serviere-Zaragoza et al., 1993a:483; Serviere-Zaragoza et 

al., 1993b:45; González-González et al., 1996:262, 407.

Gelidium crinale f. luxurians F. S. Collins in Collins, Holden and Setchell, 

1903: Exsiccate No. 1138; Collins, 1906a:111.

Gelidium crinale var. luxurians (F. S. Collins) N. L. Gardner, 1927b:277, 

pl. 46: fig. 1, pl. 47: fig. 3; Dawson, 1953a:65, pl. 4: figs. 4, 5; 

1961b:408; Dawson et al., 1964:39, pl. 31: fig. C; Dawson, 

1966a:16; 1966b:59; González-González et al., 1996:205; MateoCid et al., 2006:50.

Algae forming tufts, mostly up to 2(–5) cm tall, of sparsely, 

irregularly branched (more or less distichous) axes; branching in 

upper portions sometimes may be secund or alternate or more or 

less pinnate; axes and branches compressed, narrow, 150–300 

μm wide, and thin, 100–200 μm thick; above a basal system of 

prostrate branches, attached by short, peg-like rhizoids to substratum. Medulla of irregularly shaped cells; rhizoidal filaments 

scarce or in some few to numerous, mostly to entirely in central 

inner medulla, and either lacking or occasionally occurring in 

outer medulla. Outer cortex of rows of small pigmented cortical 

cells; inner cortex of rows of cells similar in size or up to 2 times 

larger than outer cortical cells.

Tetrasporangia within sori on upper branchlets (arranged 

in rows in young sori and apices). Cystocarps unilocular, usually 

with a single ostiole; protruding on one surface of upper branches. 
316 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Habitat. On rocks, exposed or sometimes partially 

buried in sand, in crevices, and on edges of tide pools; mid to 

low intertidal.

Distribution. Gulf of California: Playa Arenosa 

(Norse Beach), Puerto Peñasco; Nayarit to Jalisco. Eastern Pacific: Oregon; San Francisco, California, to northern Baja California; Peru.

Type Locality. “Rocky beach just north of 

Wind and Sea (‘Windansea’ surfing beach), La Jolla” (Stewart, 

1991:73), San Diego County, southern California, USA. 

Remarks. In the northern Gulf, Pterocladia media

can be similar in size and habit to some Gelidium pusillum. Thalli 

of P. media are soft and lax, with more slender axes and irregular 

branching; in contrast, those of G. pusillum are cartilaginous 

and stiff, slightly wider, with branching that tends to be more or 

less pinnate. Santelices (1999) has noted that Pterocladia media

may actually belong to Pterocladiella, and its generic placement 

needs to be tested. 

Pterocladia sonorense (E. Y. Dawson) J. S. Stewart et J. N. 

Norris, comb nov.

FIGURE 156

Gelidium? sonorense E. Y. Dawson, 1953a:75 [with taxonomic query 

of genus], pl. 5: fig. 5, pl. 21: fig. 2 [type specimen]; 1961b:409; 

Stewart and Norris, 1981:274, tbl. 1; González-González et al., 

1996:208, 393.

Prionitis delicatula sensu Dawson, 1966a:20 [in part]; 1966b:59 [non Prionitis delicatula (W. R. Taylor) E. Y. Dawson, 1961a:424].

Pterocladia capillacea sensu Stewart and Norris, 1981:279 [in part; Puerto 

Peñasco specimens only, figs. 2, 3; non Pterocladia capillacea (S. G. 

Gmelin) Bornet in Bornet et Thuret, 1876:57, which is now Pterocladiella capillacea (S. G. Gmelin) Santelices et Hommersand, 1997:118].

Algae forming loose clumps, up to 8 cm tall; composed of 

few to several semierect or spreading narrow, ligulate, stipitate, 

flat fronds, 900–1100(–1500) μm wide, 180–230 μm thick, 

that develop above a few short, stoloniferous basal branches 

attached to hard substratum by several small discs or pegs. 

Primary axes openly irregularly to pinnately branched at often 

wide, irregular intervals; branching up to 3 orders; branches 

very variable in length, thus showing no regular branching 

pattern; branches almost always about same width, tapering 

toward their base, with blunt apices. Transection of axes and 

branches sowing abundance of rhizoidal filaments throughout 

medulla and subcortex.

Tetrasporangia in narrow, elongated sori bordered by sterile margins, on middle portions of ultimate and subultimate 

branches. Cystocarpic and spermatangial thalli not known.

Habitat. On rocks, tidal platforms, and edges of tide 

pools; intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas. 

Type Locality. Puerto San Carlos, west side of 

Ensenada de San Francisco (northeast of Guaymas), Sonora, 

Gulf of California, Mexico.

Remarks. Pterocladia sonorense differs from other 

Gulf of California Gelidiales in having branches of each order 

that are nearly uniform in width but have irregular and variable 

lengths, an abundance of rhizoidal filaments (rhizines) in the medulla and subcortex, and narrow, elongated tetrasporangial sori. 

We tentatively place this species in Pterocladia but recognize that it 

may be a Pterocladiella. Once cystocarps are found and elucidated, 

its taxonomic status and generic placement and relationship to 

Pterocladiella capillacea need to be tested by molecular analyses. 

Pterocladiella Santelices et Hommersand

Pterocladiella Santelices et Hommersand, 1997:117.

Algae are usually in clumps of erect, compressed to flattened 

axes that are sparsely to more regularly branched, usually in one 

plane. The branching is regularly to irregular pinnate. Branched 

axes arise from compressed prostrate axes that are attached to 

the substratum by peg-like haptera. The single apical cell is prominent in some of the species but not always distinct in others. The 

medulla is densely packed with moderately sized medullary cells 

that outward become smaller in diameter and grade into cortex. 

Cortex is of 2–3 layers of small, pigmented cortical cells. Rhizoidal filaments (rhizines) are variable in abundance but usually 

more numerous in the medulla than in the inner cortex. 

Tetrasporangial sori are variable in size but generally elongated on the upper branches and ultimate branchlets; tetrasporangia about 25 μm in diameter. Gametangial thalli not seen in 

Gulf material. Cystocarps elsewhere reported: 500–600(–1200) 

μm in diameter, usually with single ostiole, occasionally with 2 

ostioles; borne single or sometimes more than 1, near base of ultimate branchlets and upper branches. Spermatangia in elongated 

sori; on either sides of ultimate branchlets or upper branches. 

There are two species in the northern Gulf of California.

FIGURE 156. Pterocladia sonorense: Habit (EYD-27304, US Alg. 

Coll.-40860).
NUMBER 96 • 317

KEY TO THE SPECIES OF PTEROCLADIELLA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli mostly less than 1 cm tall; main axes slender, 45–570(–750) μm wide, and thin, usually 60–120 μm thick . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. caloglossoides

1b. Thalli mostly greater than 2 cm high; main axes mostly 1.2–2.0 mm wide, and thicker, 160–370 μm thick . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. capillacea

Pterocladiella caloglossoides (M. Howe) Santelices

FIGURE 155B

Gelidium caloglossoides M. Howe, 1914:96, pl. 34: fig. 7, pl. 35: figs. 1–12; 

Hollenberg, 1942a:534; Smith, 1944: pl. 44: figs. 3, 4.

Pterocladiella caloglossoides (M. Howe) Santelices, 1998:244; Santelices, 

1999:72; Abbott, 1999:198, fig. 52A,B; Xia and Wang, 1999:81, 

figs. 1–8; L. Aguilar-Rosas et al., 2000:130; Shimada and Masuda, 

2002:170, figs. 7–10; Pacheco-Ruíz and Zertuche-González, 2002:467; 

López et al., 2004:12; Mateo-Cid et al., 2006:50.

Pterocladia caloglossoides (M. Howe) E. Y. Dawson, 1953a:76, pl. 6: fig. 1; 

Dawson et al., 1960b:15; Dawson, 1961b:410; Acleto O., 1973:31; 

Stewart, 1976:349, fig. 292; Santelices, 1977:78; Santelices and Abbott, 1978:218; Stewart and Norris, 1981:274, tbl. 1, 281; Stewart and 

Stewart, 1984:143; L. Aguilar-Rosas et al., 1985:125; Renfew et al., 

1989:3308, figs. 34–41; Ramírez and Santelices, 1991:194; Mateo-Cid 

and Mendoza-González, 1992:19; Stewart, 1992:183, fig. 4; MateoCid and Mendoza-González, 1992:20; Mendoza-González and MateoCid, 1992:16; Rodríguez-Vargas et al., 1993:448; Serviere-Zaragoza et 

al., 1993a:484; León-Tejera et al., 1993:200; González-González et al., 

1996:261.

Pterocladia parva E. Y. Dawson, 1953a:77, pl. 6: fig. 2 [type]; 1961b:410; 

Stewart and Norris, 1981:274, tbl. 1; Mendoza-González and MateoCid, 1985:32; González-González et al., 1996:262.

Algae mostly less than 1.0 cm (occasionally up to 2.0 cm) 

high; of few to several, erect to repent, very slender, flattened 

axes, mostly 45–570 μm wide and 60–120 μm thick (intertidal 

specimens can be up to 750 μm wide; subtidal specimens predominantly 60–200 μm); axes variably branched, from simple 

to sparsely, more or less pinnately to irregularly branched; above 

prostrate flattened axes (similar in sizes to erect axes), attached 

at frequent intervals to substratum by disc-like or peg-like structures developed on lower surfaces, axes sometimes also attaching to each other; decumbent repent branches also secondarily 

attached to substratum. 

Tetrasporangia often (but not always) in diagonally opposed 

V-shaped rows in apical sori. Gametangial thalli not reported in 

the northern Gulf. Unilocular cystocarps and spermatangial sori 

distal on branches on southern California subtidal thalli (Stewart and Norris, 1981); spermatangia in clusters of 2–4 below 

rounded apices (Renfew et al., 1989).

Habitat. On rocks and in tide pools; low intertidal 

to shallow subtidal, 3–12 m depths (also dredged from 28 m 

depths). 

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de Los Ángeles; Sinaloa to Jalisco. Eastern Pacific: 

Alaska to Playa Los Cerritos (vicinity of Todos Santos, Baja 

California Sur; Isla Guadalupe; Colima to Guerrero; Peru to 

northern Chile. Central Pacific: Hawaiian Islands. Western Pacific: Vietnam. 

Type Locality. Isla de San Lorenzo, off the port of 

Callao (west of Lima), Peru.

Pterocladiella capillacea (S. G. Gmelin) Santelices et 

Hommersand

FIGURE 157

Fucus capillaceus S. G. Gmelin, 1768:146, pl. 15: fig. 1 [lectotype illustration]; Womersley and Guiry, 1994:139 [epitype].

Pterocladiella capillacea (S. G. Gmelin) Santelices et Hommersand, 1997:118, 

figs. 1a, 2b, 3b, 4, 5; Santelices, 1999:73; Abbott, 1999:199, fig. 52C–F; 

Scrosati and Serviere-Zaragoza, 2000:1061; Scrosati, 2002:96, fig. 1; 

CONANP, 2002:139; Shimada and Masuda, 2002:172, figs. 11–18; 

Mateo-Cid et al., 2006:50; Santelices, 2007:294, tbl. 1. 

Gelidium corneum var. capillaceum (S. G. Gmelin) Greville, 1830:143.

Gelidium capillaceum (S. G. Gmelin) Meneghini in Frauenfeld, 1854:334; 

Kützing, 1868:18, pl. 53a–d.

Pterocladia capillacea (S. G. Gmelin) Bornet in Bornet et Thuret, 1876:57, pl. 

20: figs. 1–7; Stewart, 1968:76; 1976:350, fig. 293; Stewart and Norris, 

1981:274, tbl. 1, 279 [in part; excluding Gelidium sonorense and G. 

decompositum]; L. Aguilar-Rosas, 1981:93; Pacheco-Ruíz and AguilarRosas, 1984:76; Stewart and Stewart, 1984:143; Huerta-Múzquiz and 

Mendoza-González, 1985:48; Mendoza-González and Mateo-Cid, 

1985:32; Santelices and Stewart, 1985:25, fig. 1; Mendoza-González 

and Mateo-Cid, 1986:422; Santelices and Abbott, 1987:12; SánchezRodríguez et al., 1989:42; Mateo-Cid and Mendoza-González, 

1991:20; Ramírez and Santelices, 1991:194; Stewart, 1992:183, figs. 

1–3, 7; Mateo-Cid and Mendoza-González, 1994b:39; GonzálezGonzález et al., 1996:325, fig. 38; Anaya-Reyna and RiosmenaRodríguez, 1996:864, tbl. 1; Silva et al., 1996b:232; CONANP, 

2002:139; Pacheco-Ruíz and Zertuche-González, 2002:467; ServiereZaragoza et al., 2007:11. 

Gelidium pyramidale N. L. Gardner, 1927b:273, pl. 36, pl. 37: fig. 1, pl. 45, 

pl. 46: fig. 2.

Pterocladia pyramidale (N. L. Gardner) E. Y. Dawson, 1945e:93; 1953a:79; 

1957a:7; 1959a:20; Dawson et al., 1960b:76, pl. 18: fig. 3, pl. 19: fig. 1; 

Dawson, 1961b:410; Stewart, 1968:76–81; Acleto O., 1973:32; Brusca 

and Thomson, 1975: 37; Stewart and Stewart, 1984:143 ; GonzálezGonzález et al., 1996:262.

Pterocladia mexicana W. R. Taylor, 1945:159, pl. 35; González-González et 

al., 1996:262.

Pterocladia complanata Loomis, 1949:4, pl. 6: figs. 1, 2, pl. 7: figs. 

1–4, pl. 10 [type specimen]; Dawson, 1953a:78; 1961b:410; Silva, 

1978:260; Mendoza-González and Mateo-Cid, 1985:32; MendozaGonzález and Mateo-Cid, 1986:422; González-González et al., 

1996:262.
318 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Algae forming loose tufts or clumps; of several erect, flattened axes, 4–9 cm high, (0.6–)1.2–2.0 mm wide, (100–)160–

370 μm thick; arising from a creeping rhizoidal base, attached 

by peg-like haptera; branching 2–5 orders, more or less to regularly pinnate, first order branches at up to 5-mm intervals and 

up to 4.5 cm in length, and second order branches at intervals 

of 0.1–1.5 mm, narrower, 0.2–1.0 mm wide. Medulla densely 

packed; medullary cells, (12–)20–30 μm in diameter; becoming 

smaller outward, grading into cortex of 2–3 layers of small, pigmented cortical cells; outermost cells slightly elongated, about 

5.0–7.0 μm tall. Rhizoidal filaments (rhizines) varying from several to being numerous in medulla (generally more concentrated 

in middle of medulla).

Tetrasporangial sori, variable in size, generally elongated 

from middle to distal ends of upper branches and ultimate 

branchlets; tetrasporangia 40–48 μm long and 16–28 μm in diameter. Gametangial thalli not seen in Gulf material. Cystocarps 

elsewhere reported: 500–600(–1200) μm in diameter, usually 

with single ostiole; developed near apices of ultimate branchlets 

and upper branches. Spermatangia in elongated sori; on either 

sides of ultimate branchlets or upper branches; spermatangial 

parent cells, 8–10 μm long and 1.5–2.0 μm in diameter (after 

Shimada and Masuda, 2002). 

Habitat. On rocks and in tide pools; mid intertidal 

to shallow subtidal. 

Distribution. Gulf of California: Bahía de Los 

Ángeles; Isla Coronado (Isla Smith). Eastern Pacific: Santa Barbara, southern California to Punta Lobos (vicinity of Todos 

Santos), Baja California Sur; Isla Guadalupe; Isla Cedros; Islas 

San Benitos; Rocas Alijos; Isla Clarión (Islas Revillagigedo); Galápagos Islands; Ecuador; Peru; Rapa Nui (Easter Island; Isla 

de Pascua). Central Pacific: Hawaiian Islands. Western Pacific: 

Japan; China; Taiwan.

Type Locality. Mediterranean Sea (Gmelin, 1768). 

Lectotype: illustration of Gmelin (1768: pl. 15: fig. 1); epitype 

specimen selected by Womersley and Guiry (1994:139).

Remarks. Pterocladiella capillacea, the type species 

for the genus, has been widely reported in tropical to warmtemperate seas (Womersley and Guiry, 1994; Santelices, 1999). 

An economically important species, P. capillacea provides a highquality agar and has been commercially harvested in southern 

California and Baja California (Stewart, 1991). Pterocladiella 

capillacea had generally been considered to be a broadly defined 

species that included a wide range of morphological variation 

(Stewart, 1968). More recently in an rbcL analysis, the Japanese 

“P. capillacea-complex” was found to contain three species that 

were molecularly and morphologically distinct (Shimada et al. 

2000; Shimada and Masuda, 2002).

Pterocladiella capillacea is probably in the northern Gulf, 

but its presence awaits the finding of cystocarpic specimens and 

molecular confirmation in comparisons with type locality Mediterranean and Western Pacific materials. Morphologies that are 

similar to “Gelidium decompositum” sensu Dawson (1957a, 

1959a) could probably be included here (Dawson, 1961b) but 

not specimens of G. decompositum Setchell et N. L. Gardner 

(1924) sensu stricto. Although the Gulf of California species 

G. decompositum and Pterocladia sonorense were tentatively 

treated as forms of Pterocladiella capillacea by Stewart and Norris (1981, as “Pterocladia capillacea”), limits of these species are 

not fully understood, and for now, they are treated as separate 

species from each other and from P. capillacea until their taxonomic status can be genetically tested and their phylogenetic relationships can be elucidated.

Some specimens of the northern Gulf P. capillacea are 

similar in habit to the southern California P. pyramidale (N. L. 

Gardner) E. Y. Dawson (1945e; type locality: La Jolla, California), which is generally accepted as being conspecific, but it too 

should be genetically compared with the Mediterranean (type 

locality) Pterocladiella capillacea.

Gigartinales

Gigartinales F. Schmitz in Engler, 1892:18

Members of the Gigartinales exhibit a wide range of diverse morphologies. The erect species can be cylindrical to compressed or flattened and blade-like. Most of these are repeatedly 

branched; others are blade-like and entire, divided, or lobed. 

There are also a few crustose species, and some that are minute 

parasites. Thalli are uniaxial or multiaxial in structure and internally may be filamentous or pseudoparenchymatous. 

Tetrasporangia may be cruciately or zonately divided. The 

Gigartinales differs from the Cryptonemiales Kylin by the formation of the auxiliary cells from converted vegetative cells. In the 

Cryptonemiales the auxiliary cells differentiate before fertilization, 

but in the Gigartinales they are intercalary cells of a cortical filament or subsidiary and do not arise in specialized branches. The 

FIGURE 157. Pterocladiella capillacea: A, B. Habits (JN-4611b, US 

Alg. Coll.-159295). 
NUMBER 96 • 319

carpogonial branch is oriented inward or outward, and postfertilization gonimoblast development may be inward or outward. 

The zygote is the result of direct fusion or transfer via connecting 

filaments or cells. Carposporophytes usually have a fusion cell and 

extensive sterile tissue; however, in some members the carposporophyte is almost entirely composed of carposporangia. 

Remarks. Clarification of the vegetative and reproductive developmental morphology, particularly the ontogeny of 

reproductive structures, is needed before the taxonomy is well 

understood for many members of this group.

The Gigartinales are represented by nine of its families in 

the northern Gulf of California.

KEY TO THE FAMILIES OF GIGARTINALES IN THE NORTHERN GULF OF CALIFORNIA

1a. Auxiliary cells terminal or intercalary in specialized branches that develop laterally from inner cortical or outer medullary 

cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Auxiliary cells transformed from ordinary vegetative cells or from vegetative cells of specialized reproductive short 

filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

2a. Nonprocarpic; carpogonial branch single, carpogonium terminal on 5- to 10-celled branch; auxiliary cell 1–4 cells from 

end of 5- to 12-celled auxiliary cell branch; fertilized carpogonium connecting with a subterminal cell of carpogonial 

branch, producing connecting filaments that fuse with auxiliary cells prior to development of carposporophytes. Gulf 

members uniaxial in structure; soft and mucilaginous; tetrasporangia zonately divided . . . . . . . . . . . . . . Dumontiaceae

2b. Procarpic or nonprocarpic; carpogonial branch single to several per supporting cell; carpogonial branch and auxiliary cell 

branch systems both with large rounded to lobed subsidiary cells; thalli multiaxial in structure; texture slippery but not 

mucilaginous; tetrasporangia cruciately divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Medulla with elongate, sometimes dendroid refractive cells; connecting filaments contact both auxiliary cells and special 

accessory filaments, and both issue gonimoblasts that develop carposporangia . . . . . . . . . . . . . . . . . . Crossocarpaceae

3b. Medulla with stellate refractive cells; connecting filaments contact only auxiliary cells, and only the auxiliary cells issue 

gonimoblasts that develop carposporangia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kallymeniaceae

4a. Thallus multiaxial (gametophytes and tetrasporophytes isomorphic or a few heteromorphic, with erect gametophytes and 

a crustose tetrasporophyte); tetrasporangia zonately or cruciately divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

4b. Thalli of Gulf of California members uniaxial; tetrasporangia zonately divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

5a. Thalli procarpic; tetrasporangia cruciately divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

5b. Thalli nonprocarpic; tetrasporangia zonately divided . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6a. Medulla pseudoparenchymatous throughout; tetrasporangia in catenate rows, developed within nemathecia on surface 

produced from outer cortical cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Phyllophoraceae

6b. Medulla a meshwork of elongated filaments; tetrasporangia formed in inner cortical or medullary sori . . . . Gigartinaceae

7a. Carpogonial branches develop directed outward toward surface, with comparatively straight trichogynes . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Dicranemataceae

7b. Carpogonial branches develop directed inward toward inner cortical layer/outer medulla, with reflexed trichogynes 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Solieriaceae

8a. Gulf members with slightly compressed to flattened branches; axial filament cells distinct throughout in transection, medulla 

usually pseudoparenchymatous; cystocarps conspicuous, sessile on branches, usually nonostiolate . . . . . . Cystocloniaceae

8b. Thalli of Gulf members wiry; axial filament cells not always distinct in transection; medulla of lax, often widely separated 

filaments; cystocarps internal, usually ostiolate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Caulacanthaceae

Caulacanthaceae

Caulacanthaceae Kützing, 1843:389.

Algae in this family are erect, often bushy, with terete, usually entangled, axes that branch laterally or divaricately. Growth 

is uniaxial with a single apical cell evident at branch tips. There 

are two periaxial cells per axial cell, and in some species the 

central axial filament can also be seen. In other species this axis 

is obscured by the medulla of rounded cells, with branched filaments that grade into smaller cells of the cortex. The subcortex 

is composed of large cells, and the outer cortex is composed of 

small cells. 

Tetrasporangia are zonately divided and scattered in the 

slightly thickened cortex of the branches. Cystocarps are internal, 

developing around the central axis. The gonimoblast develops 

outward from the large fusion cell of the female reproductive 

apparatus. Carposporangia are borne terminally on short gonimoblast filaments. 

One genus of the Caulacanthaceae is known in the northern 

Gulf of California.

Caulacanthus Kützing

Caulacanthus Kützing, 1843:395.

Algae are erect, with terete axes, sparsely to moderately branched, that arise from prostrate branches attached to 

the substrate by small discs. Internally, there is a single, usually conspicuous, axial filament with two periaxial cells and a 
320 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

pseudoparenchymatous medulla that at first is loosely arranged 

but later becomes densely arranged toward the surface, with filaments alternately branched from the axial filament. The outer 

cortex is compact, thick, and cartilaginous, with thick-walled 

outer cortical cells. 

Tetrasporangia are zonately divided, scattered over branches. 

Gametophytes are monoecious. Carpogonial branches are threecelled. After fertilization the carpogonium develops a single, short 

connecting filament. The gonimoblast develops around the central axial filament of the lateral branchlets, with a central fusion 

cell with numerous rows of cells radiating outward; the outer two 

to three layers produce carposporangia. Each carposporangium is 

single and terminal. Cystocarps are embedded and swollen, often 

protruding in upper portions of axes and branches, with an ostiole. Spermatangia are in sori near the branch apices.

Remarks. The number and distinctiveness of some 

species of Caulacanthus are uncertain, although recent genetic 

analyses suggest there may be cryptic or overlooked species that 

require further study. 

One species is known in the northern Gulf of California. 

Caulacanthus okamurae Yamada

Caulacanthus okamurae Yamada, 1933:278, as C. okamurai; Okamura, 

1936:621, fig. 294; Tseng, 1983:112, pl. 59: fig. 1; H.-G.Choi and 

Nam, 2001:315, figs. 4–17; H.-G. Choi et al., 2001b:353.

Caulacanthus ustulatus sensu Dawson, 1961a:224, pl. 26: fig. 3; 1961b:429; 

1966a:23; Searles, 1968:46 (in part, excluding C. okamurae); 

González-González et al., 1996:184; Yoshida, 1998:657, fig. 3-42B,C; 

Abbott, 1999:104, fig. 20D–F; Xia and Zhang, 1999:10, fig. 6; Y.-P. 

Lee, 2008:332, figs. A–C; Bernecker, 2009:CD-Rom p. 62; FernándezGarcía et al., 2011:60 [non Caulacanthus ustulatus (Mertens ex Turner) 

Kützing, 1843:395; 1868:3, pl. 8: figs. a–c; basionym: Fucus acicularis

Wulfen var. β ustulatus Mertens ex Turner, 1809:143, figs. 126a–f]. 

Caulacanthus indicus sensu Dawson, 1957c:17, as Caulacanthus sp. aff. 

C. indicus; 1961b:429 [non Caulacanthus indicus Weber-van Bosse, 

1921:222, fig. 67].

Endocladia complanata sensu Okamura, 1908:121, pl. 27: figs. 12–20, pl. 

28: figs. 13–17 [non Endocladia complanata Harvey, 1860:333 (see 

Yamada, 1933:278); Dawson, 1959b:24; Searles, 1968:47]. 

Hypnea esperi sensu Dawson, 1944a:292 [in part; non Hypnea esperi Bory 

de Saint-Vincent, 1828:157, nom. illeg.; see Silva et al., 1987, 1996a].

Thalli forming small clumps or mats, 1(–3) cm high and 

to 6 cm wide, of loosely entangled, terete, erect and prostrate 

irregularly branched axes, 150–200 μm in diameter; attached 

to substrate and secondarily to other branches by numerous 

small discs; ultimate branchlets subulate. Medulla a large, thickwalled, central filament; surrounded by a cortex of inner and 

outer cortical cells

Tetrasporangia zonate, in swollen parts of ultimate branchlets. Cystocarpic and spermatangial thalli not known in the Gulf 

of California. 

Habitat. On rocks; mid intertidal. 

Distribution. Gulf of California: Puerto Peñasco; 

Bahía Tecopa; Isla Turner (of SE end of Isla Tiburón); Punta San 

Pedro (near Guaymas); Bahía Agua Verde. Eastern Pacific: Los 

Angeles County to San Diego Bay (southern California); Santa 

Catalina Island and Anacapa Island (California Channel Islands); 

Isla Cedros (Baja California) to Isla Santa Margarita, off Bahía 

Magdalena (Baja California Sur); Costa Rica. Central Pacific: 

Hawaiian Islands. Western Pacific: China; Taiwan; Korea; Japan. 

Type Locality. Probably Hokkaidô, Japan; although not specifically designated, distribution was given as 

“Hokkaidô to Formosa” (Yamada, 1933:278).

Remarks. Caulacanthus okamurae forms inconspicuous small tufts or mats in the northern Gulf. It is also often 

unevenly distributed in the intertidal zone and may be easily 

overlooked. Caulacanthus okamurae Yamada (1933) is considered by some to be a unique western Pacific species (e.g., Tseng, 

1983; H.-G. Choi and Nam, 2001; H.-G. Choi et al., 2001b). 

Earlier, Searles (1968) had concluded C. okamurae was probably 

not distinct on a morphological basis from C. ustulatus (generitype; lectotype locality: Cádiz, Iberian Peninsula, SW Spain).

Since then the two have generally been considered conspecific 

(e.g., Rueness, 1997; Yoshida, 1998). 

Rueness and Rueness (2000, as C. ustulatus) found that 

Caulacanthus from Brittany, France, was in a lineage genetically 

identical with those of China and Japan, and they concluded that 

it was introduced from the Pacific, possibly along with oysters 

from Japan. However, their “Pacific group” was separate from 

the “southern Europe group” (Gibraltar and Portugal), and, noting some minor morphological differences between them, they 

raised the question of whether the groups were conspecific or 

not. Caulacanthus was recently discovered in intertidal communities of southern California (Murray et al., 2007), and it was 

found by Whiteside et al. (2007, as C. ustulatus) to be genetically 

close to the Asian C. okamurae. Zuccarello et al. (2002b) found 

three distinct lineages of Caulacanthus—a Pacific lineage (China, 

Korea, United States, Philippines, and Australia), an Atlantic 

lineage (Spain and Portugal), and another cryptic lineage—but 

suggested they be referred to as one cosmopolitan species, C. ustulatus. Caulacanthus ustulatus has been reported in the eastern Pacific from British Columbia to Washington (Norris and 

Wynne, 1969; Gabrielson and Scagel, 1989). Norris and Wynne 

(1969) noted little morphological difference between their northeastern Pacific specimens and Dawson’s (1961a, 1966a) from the 

northern Gulf of California. At this point the morphological distinctiveness of these species remains problematic.

Although more work is needed, on the basis of the genetic 

evidence, C. ustulatus and C. okamurae are for now treated as 

two species. Those of the northern Gulf referred to C. okamurae will need to be genetically tested and further compared with 

eastern Pacific, Asian, and European materials, including type 

locality specimens, to elucidate their phylogenetic relationships 

and taxonomic status.

Cystocloniaceae

Cystocloniaceae Kützing, 1843:390, 404; Saunders et al., 2004:46, 58, 

figs. 4, 5.

Hypneaceae J. Agardh, 1851:viii, 430.
NUMBER 96 • 321

Algae are commonly cushion-like, bushy, or tufted in 

growth form and composed of cylindrical, compressed to flattened branches. In some species the branches have numerous 

short, spine-like lateral branchlets. Growth is uniaxial, and the 

single apical cell is usually evident. The medulla consists of a single axial filament surrounded by large pseudoparenchymatous 

cells. The cortex is of small cells.

Tetrasporangia are zonately divided and borne in sori, which 

partly or completely surround short, lateral branchlets. In the female reproductive apparatus, the supporting cell of the three-celled 

carpogonial branch bears an auxiliary cell. Cystocarps have the 

gonimoblast associated with nutritive filaments from the surrounding pericarp, and an ostiole is present in some and absent in others.

Remarks. As currently understood, the Cystocloniaceae includes 14 genera, two of which are known in Pacific Mexico (Dawson, 1961a), the free-living Hypnea J. V. Lamouroux 

and the parasitic Hypneocolax Børgesen (1920).

There is one genus of the Cystocloniaceae found in the Gulf 

of California.

Hypnea J. V. Lamouroux 

Hypnea J. V. Lamouroux, 1813:131.

Algae are erect, tufted, or repent, cylindrical to subcylindrical or compressed, with a main axis and branches, which are 

attached by a discoid holdfast and lower network of entangled 

branches with secondary discoid holdfasts. The main axis is 

often obscured by irregular and often repeated branching of determinate and indeterminate branches (appearing similar to the 

main axis). Branches are usually slender and may be straight or 

sometimes have spinose branchlets or curled or hooked branchlets. Uniaxial in structure, the medulla surrounding the axial filament cell is composed of large cells with or without lenticular 

thickenings. In some there are smaller periaxial cells and inner 

medullary cells around the axial cell. The cortex consists of successively smaller cells toward the surface. 

Tetrasporangia are zonately divided and aggregated within 

short, often swollen, branchlets or proliferations. Cystocarps are 

globose to hemispherical, surrounded by a pericarp lacking an 

ostiole, and borne on branches or short branchlets. Spermatangia are in sori, often whitish, on the surface of portions of ultimate branchlets. 

Remarks. The genus Hypnea, with over 60 species, 

is widespread in subtropical to tropical seas. Several are edible 

species, e.g., H. cervicornis is eaten in China (Xia and Wang, 

1997) and in parts of the Pacific and Asia (Payri et al., 2000, 

as “H. spinella”), although it is not commonly eaten in Hawaii 

(Fortner, 1978). Some species of Hypnea are of commercial potential and are harvested or cultivated for their phycocolloid 

products, which are used as thickening or emulsifying agents, 

such as kappa carrageenans (Mshigeni, 1976c; Santos and 

Doty, 1979) and hypnean or a gelan (Hoppe, 1969; Masuda et 

al., 1997).

The genus is in need of detailed studies of the type specimens and type locality material, as species limits are often poorly 

understood and many of the species apparently have overlapping morphologies or have been misidentified or confused with 

other taxa. The vegetative and reproductive morphologies and 

phenotypic variation of each taxon need elucidation, and DNA 

studies will be helpful to clarify their phylogenetic relationships 

and taxonomic status. 

Tetrasporangial branchlets, usually considered to be of 

determinate growth (e.g., Dawson et al., 1964), were found to 

be of indeterminate growth in cultured Hawaiian H. cervicornis (Mshigeni, 1976e). These reproductive branchlets continued 

vegetative growth even after spore shedding, and if they became 

detached, they produced a holdfast on contact with substratum, 

became attached, and developed new branches. This phenomenon can occur in natural populations and would be an important 

method of vegetative propagation. 

Dawson (1961a) referred one species from Mazatlán in the 

southern Gulf, with doubt, to the Indian Ocean Hypnea spicifera

(Suhr) Harvey in J. Agardh (1847; basionym: Gracilaria spicifera

Suhr, 1834). 

Six species of Hypnea are found in the northern Gulf of 

California. 

KEY TO THE SPECIES OF HYPNEA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thallus compressed to flattened, at least in part . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Thalli essentially terete throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2a. Low-growing mats or clumps; branches mostly compressed to flattened, 0.5–2.0 mm wide, often attached to each other; 

surface layer of cortex of uniformly small (8–10 μm) cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. pannosa

2b. Entangled around other algae; branches compressed, 600–750 μm wide; surface layer of cortex composed of cells with 

great range in size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. volubilis

3b. Thalli erect, comparatively delicate; of freely branched, loose and lax, terete branches . . . . . . . . . . . . . . . . . . . . . . . . 4

3b. Thalli low growing to partially erect; forming mats or clumps; of entangled; comparatively coarse, branches, with or 

without spine-like laterals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4a. Thallus without a distinct main axis; branches more or less uniform diameter throughout; mostly 250–600(–1000) μm in 

diameter; branching more or less irregularly divaricately dichotomous . . . . . . . . . . . . . . . . . . . . . . . . . . . H. cervicornis

4b. Thallus with a definite main axis; branching monopodial; axes up to 2000 μm in diameter; branches reduced in diameter 

upward . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. valentiae
322 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

5a. Thallus bushy or in clumps, of relatively coarse axes, 1.5–2.5 mm in diameter, with suberect (repent) entangled tapering 

branches; apical cell not evident . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. johnstonii

5b. Thallus forming a clump of slender branches, up to 600 μm in diameter, semicartilaginous; irregularly, densely branched; 

with spine-like laterals; apical cell evident . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. spinella

Hypnea cervicornis J. Agardh

FIGURE 158

Hypnea cervicornis J. Agardh, 1852a:451; Taylor, 1945:228; Dawson, 

1961a:234, pl. 34: figs. 3, 4, pl. 35: fig. 3; 1966a:24; Huerta-Múzquiz 

and Tirado-Lizárraga, 1970:128; Norris, 1973:12; Huerta-Múzquiz 

and Garza-Barrientos, 1975:9, 11; Mshigeni, 1976a:217; 1976b:223, 

figs. 1–12; 1976c:227, figs. 1–4; 1976d:309, fig. 5; 1976f:341, figs. 

1, 4; 1978a:868, figs. 1, 2; Huerta-Múzquiz, 1978:336; Stewart and 

Stewart, 1984:144; Mendoza-González and Mateo-Cid, 1985:30; 

Ibarra-Obando and Aguilar-Rosas, 1985:96; Sánchez-Rodríguez et 

al., 1989:43; León-Tejera et al., 1993:200; Mendoza-González et al., 

1994:107; González-González et al., 1996:318, 412; Anaya-Reyna 

and Riosmena-Rodríguez, 1996:864, tbl. 1; Xia and Wang, 1997:196: 

figs. 6–10; Riosmena-Rodríguez et al., 1998:27; Abbott, 1999:113, fig. 

24A; Cruz-Ayala et al., 2001:191; CONANP, 2002:140; Bernecker, 

2009:CD-Rom p. 62. 

Hypnea esperi sensu Kützing, 1868:9, pl. 26: figs. a–c [non Hypnea esperi Bory de Saint-Vincent, 1828:157, nom. illeg.; see Silva et al., 

1996a:298]. 

Algae, semierect, epiphytic, clumped or mat-like on substratum or forming loosely entangled soft masses; 1.5–3.0(–6.0) cm 

high; without definite main axes, of narrow, terete branches of 

more or less uniform diameter throughout (not narrowing or tapering upward), but ranging from (110–)250 to 600(–1000) μm 

in diameter. Attached by discoid holdfasts developed from basal 

rhizoids (Mshigeni, 1976b). Indistinct primary axes, irregularly 

divaricate-dichotomously branched, with few to many straight 

or curved, antler-like branchlets with acute apices.

Tetrasporangia in swollen sori, encircling short branchlets 

below tips. Sexual reproduction not known in Gulf of California 

material. As reported in Hawaii (Mshigeni, 1976f): cystocarps 

globose, up to 1000 μm in diameter; on axes and branchlets; 

spermatangia in slightly swollen sori, on branchlets below apices. 

Habitat. Epiphytic on various algae or entangled on 

gorgonians or growing loosely on rocks or shells; mid to low 

intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de San Lucas; Mazatlán. Eastern Pacific: Isla Guadalupe 

(off Baja California) to Isla Magdalena and Bahía Magdalena, 

Baja California Sur; Isla Socorro and Isla San Benedicto (Islas 

Revillagigedo); Guerrero to Oaxaca; El Salvador; Costa Rica; 

Panama. Central Pacific: Hawaiian Islands. Western Pacific: 

China; Japan; Korea.

Type Locality. Not specifically designated; 

“oceano atlantico calidiori, ad oras Brasiliae, ad insulas Indiae 

occidentialis et littus mexicanum; in oceano indico ad insulam 

Mauritii” (Agardh, 1852a:452); localities given are in the warm 

Atlantic from Brazil, the West Indies, and Mexico, and in the 

Indian Ocean from Mauritius. 

Remarks. Hypnea cervicornis as currently interpreted is widespread in tropical seas (Mshigeni, 1978b). There 

has been much confusion on the taxonomic separation of H. cervicornis from H. spinella (e.g., Lawson and John, 1987; Guiry 

and Guiry, 2008–2010). On the basis of sometimes overlapping 

morphologies, some considered these two species to be one, as 

H. spinella, e.g., Haroun and Prud’homme van Reine (1993) 

from Macaronesia and Yamagishi and Masuda (1997) from 

Japan. Others have questioned if H. cervicornis should be conspecific with H. spinella (e.g., Cribb, 1983; Xia and Wang, 1997; 

Xia and Zhang, 1999). Since these two are morphologically relatively distinct in the Gulf of California, they are herein treated 

as being separate, following Guiry and Guiry (2008–2010). The 

elucidation of H. cervicornis and H. spinella on the basis of 

morphological and molecular studies of the type and type locality material is needed. Future studies comparing the molecular 

findings of type locality specimens have to be done on Gulf of 

California material referred to H. cervicornis and H. spinella to 

clarify their taxonomic status. 

FIGURE 158. Hypnea cervicornis: Habit (EYD-27213, US Alg. 

Coll.-40586).
NUMBER 96 • 323

Hypnea johnstonii Setchell et N. L. Gardner

Hypnea johnstonii Setchell et N. L. Gardner, 1924:758, pl. 23: figs. 19–21, 

pl. 57; Dawson, 1944a:292; Taylor, 1945:227; Dawson, 1958:71; 

1959a:25; 1961a:236; 1961b:428; 1966a:24; Norris, 1973:12; 

Abbott and Hollenberg, 1976:489, fig. 433; Huerta-Múzquiz, 

1978:337; Littler and Littler, 1981:149, fig. 2; Mendoza-González 

and Mateo-Cid, 1985:30; Sánchez-Rodríguez et al., 1989:43; 

Mendoza-González and Mateo-Cid, 1992:19; Serviere-Zaragoza 

et al., 1993a:484; Mateo-Cid and Mendoza-González, 1994b:40; 

González-González et al., 1996:226; Anaya-Reyna and RiosmenaRodríguez, 1996:864, tbl. 1; Riosmena-Rodríguez et al., 1998:27; 

Mateo-Cid et al., 2000:65; Cruz-Ayala et al., 2001:191; CONANP, 

2002:140; Riosmena-Rodríguez et al., 2005a:33; Serviere-Zaragoza 

et al., 2007:10; Pacheco-Ruíz et al., 2008:209; Pérez-Estrada et al., 

2012:191. 

Algae of rigid, branched axes, 7–10(–15) cm long; forming dense, low-growing clumps, spreading to 20 cm or more, 

or sometimes becoming suberect above basal caespitose portion; 

attached by discoid holdfasts from lowermost branches. Main 

axes terete to only slightly compressed, coarse, 1.5–2.5 mm in 

diameter, branching near decumbent base into long, rigid, tapering, branches mostly with numerous short branchlets along 

sides; branches reduced in length upward; apices rounded, single 

apical cell not evident. 

Tetrasporangia zonately divided; throughout very short, 

simple to compound, branchlets. Sexual reproduction unknown. 

Habitat. On rocks, pebbles, and shells; mid to low 

intertidal, occasional in shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía Agua Verde; Isla San Pedro Nolasco; Punta Arena to 

Cabo Pulmo-Los Frailes; Mazatlan, Sinaloa to Jalisco. Eastern 

Pacific: Newport Harbor (southern California); Isla Cedros and 

Islas San Benitos (off Baja California); Punta Santa Rosaliita 

(Punta Santa Rosalía; Punta Santa Rosalillita), Baja California 

to Punta Lobos (vicinity of Todos Santos), Baja California Sur; 

Isla San Benedicto (Islas Revillagigedo).

Type Locality. On intertidal rocks; Isla Estanque 

(Pond Island), off southeastern end of Isla Ángel de la Guarda, 

Gulf of California, Mexico. 

Remarks. Hypnea johnstonii is apparently an annual 

species in the northern Gulf, particularly abundant in the spring 

and maturing in the summer. It can be recognized in the field by 

its caespitose (low–growing, clump-like) habit, distinctive coarse 

branches, and the dark blackish red color, which often has an 

iridescent bluish sheen (becoming blackish upon drying). Millar 

(1990) has reported H. johnstonii from the southwestern Pacific 

from New South Wales, Australia.

Hypnea pannosa J. Agardh

Hypnea pannosa J. Agardh, 1847:14; Kützing, 1868:9, pl. 27: figs. i, k; 

Setchell and Gardner, 1924:758; Okamura, 1907:47, pl. X: figs. 18–20; 

Tanaka, 1941:247, fig. 20; Dawson, 1944a:291; Taylor, 1945:227, pl. 

71: fig. 2; Dawson, 1961a:236, pl. 35: figs. 4, 5; 1961b:428; 1966a:24; 

Huerta-Múzquiz and Tirado-Lizárraga, 1970:128; Chávez-Barrear, 

1972b:269; Norris, 1973:12; Mshigeni, 1978a:874, figs. 8, 11, 12; 

Huerta-Múzquiz, 1978:339; Pedroche and González-González, 

1981:66; Schnetter and Bula-Meyer, 1982:137, pl. 21: fig. E; Tseng, 

1983:100, pl. 53: fig.1; Mendoza-González and Mateo-Cid, 1985:30; 

Mendoza-González and Mateo-Cid, 1986:424; Salcedo-Martínez et al., 

1988:83; Sánchez-Rodríguez et al., 1989:43; Mateo-Cid and MendozaGonzález, 1992:20; Mendoza-González and Mateo-Cid, 1992:19; 

Serviere-Zaragoza et al., 1993a:484; León-Tejera et al., 1993:200; 

Mateo-Cid and Mendoza-González, 1994b:40; Mendoza-González 

et al., 1994:107; González-González et al., 1996:318; Yamagishi and 

Masuda, 1997:145, figs. 22–25; Chiang, 1997:173, fig. 14; Xia and 

Wang, 1997:203, figs. 33–38; Yoshida, 1998:742, fig. 3-62E,F; Abbott, 

1999:117, fig. 25A; Xia and Zhang, 1999:87, fig. 52; Mateo-Cid et al., 

2000:65; Cruz-Ayala et al., 2001:191; CONANP, 2002:140; López et 

al., 2004:11; Hernández-Herrera et al., 2005:148; Serviere-Zaragoza et 

al., 2007:10; Pacheco-Ruíz et al., 2008:209; Bernecker, 2009:CD-Rom 

p. 62; Fernández-García et al., 2011:62.

Hypnea nidulans sensu Dawson, 1944a:291; 1959a:25; Pacheco-Ruíz et al., 

2008:209 [non Hypnea nidulans Setchell, 1924:161].

Algae forming densely entangled irregularly shaped mats or 

clumps, up to 6 cm thick; of subcartilaginous and brittle (often 

easily breaking); subterete to compressed (sometimes flattened) 

branches, 0.5–2.0 mm in diameter; branches often adhering to 

each other; ultimate branchlets short, with acute apices; attached 

by a primary discoid holdfast and by secondary discoid holdfasts 

from entangled caespitose lower branches. Branching in more 

than 1 plane; irregularly alternate and close together, occasionally appearing pinnate; lateral proliferations usually absent or 

rare. In transection, central axial cell surrounded by large medullary cells; cells becoming smaller to outer cortex of small cells; 

lenticular thickenings absent. 

Tetrasporangia zonate, mostly 30–60 μm long, 12–26 μm in 

diameter; developing initially on one side in the lower, middle, or 

upper portions, later extending around swollen ultimate branchlets, 0.7–3.0 mm long, 400–650 μm in diameter (after Yamagishi 

and Masuda, 1997). Sexual reproduction not found in Gulf of 

California material. 

Habitat. On rocks or various substrate, tidal platform and in tide pools; mid to low intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena; Isla Estanque (Isla Pond) to Isla Turner, off 

SE end of Isla Tiburón (Islas de la Cintura); Isla San Pedro Nolasco; Mazatlán, Sinaloa to Jalisco; Isla María Magdalena (Islas 

Marías; Islas Tres Marías). Eastern Pacific: Bahía Tortugas (inside southeast Bahía San Bartolomé) to Playa Los Cerritos (south 

of Todos Santos), Baja California Sur; Isla San Benedicto and 

Isla Socorro (Islas Revillagigedo); Colima to Oaxaca; El Salvador; Costa Rica; Panama; Colombia. Central Pacific: Hawaiian 

Islands. Western Pacific: Japan; Taiwan; China.

Type Locality. San Agustín (St. Augustin), Oaxaca, Pacific Mexico.

Remarks. Hypnea pannosa can be distinguished 

from other clumping or mat-forming Gulf species by its axes and 

branches of uniform width (not tapering or becoming narrower 
324 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

upward) and tetrasporangia that are usually on one side of a 

branchlet (not surrounding it). 

The relationship of Hypnea pannosa to another species, H. 

nidulans Setchell (1924), requires investigation. Tanaka (1941) 

and Dawson (1944a) recognized Hypnea pannosa and H. nidulans as distinct, but later, Dawson (1961a) considered them to 

be conspecific (see also Chiang, 1997; Yamagishi and Masuda, 

1997; Lewmanomont, 1997; South, 2004). However, the Pacific 

Mexico H. pannosa and the South Pacific H. nidulans, described 

from Tutuila Island (American Samoa), are probably different 

species (see also Tanaka and Phạm-Hoàng, 1962; Silva et al., 

1996a; Lobban and Tsuda, 2003).

Hypnea spinella (C. Agardh) Kützing

Sphaerococcus spinellus C. Agardh, 1822:323.

Hypnea spinella (C. Agardh) Kützing, 1847:23; Taylor, 1945:228; Dawson, 

1961a:238, pl. 34: fig. 2; 1961b:428; Huerta-Múzquiz and TiradoLizárraga, 1970:128; Chávez-Barrear, 1972b:269; Huerta-Múzquiz, 

1978:338; Huerta-Múzquiz and Mendoza-González, 1985:50; 

Mendoza-González and Mateo-Cid, 1986:424; Salcedo-Martínez et 

al., 1988:83; Dreckmann et al., 1990:30; Mateo-Cid and MendozaGonzález, 1992:20; Mendoza-González and Mateo-Cid, 1992:19; 

Serviere-Zaragoza et al., 1993a:484; León-Tejera et al., 1993:200; 

Mateo-Cid et al., 1993:47; Stout and Dreckmann, 1993:10; MateoCid and Mendoza-González, 1994b:40; Mendoza-González et al., 

1994:107; González-González et al., 1996:319; Silva et al., 1996a:307; 

Mateo-Cid et al., 2000:65; L. Aguilar-Rosas et al., 2000:131; LeónTejera and González-González, 2000:327 [as H. aff. spinella]; 

L. Aguilar-Rosas et al., 2002:234; López et al., 2004:12; HernándezHerrera et al., 2005:148; Mateo-Cid et al., 2006:56; Serviere-Zaragoza 

et al., 2007:10; Bernecker, 2009[in part]:CD-Rom p. 62; CastañedaFernández de Lara et al., 2010:199; Fernández-García et al., 2011:62.

Gigartina spinella (C. Agardh) Greville, 1830: lviii.

Algae usually very entangled, forming low-growing tufts or 

mats; of somewhat cartilaginous, irregularly and often densely 

branched terete axes, 400–600 μm in diameter; branching multifarious; branches often with short, spine-like ultimate branchlets with acute apices; branches often attached to each other and 

to substratum by discoid attachments. Medulla with lenticular 

thickenings. 

Tetrasporangia developed terminally on short branchlets. 

Cystocarpic and spermatangial not observed in Gulf. 

Habitat. On rocks or sometimes epiphytic on or entangled with other algae; high to low intertidal.

Distribution. Gulf of California: Piedras del Burro 

(Gulfo de Santa Clara) to Cabeza Ballena; Mazatlán, Sinaloa to 

Jalisco. Eastern Pacific: Bahía Sebastián Vizcaino, Baja California to Playa Los Cerritos (south of Todos Santos), Baja California Sur; Isla Clarión and Isla Socorro (Islas Revillagigedo); 

Colima to Oaxaca; El Salvador; Costa Rica. 

Type Locality. “Indiae occidentalis” (C. Agardh, 

1822); in coral; West Indies, Caribbean Sea (Dawson, 1961a).

Remarks. There has been much debate as to whether 

Hypnea spinella should be a distinct species (e.g., Lawson and 

John, 1987; Chiang, 1997; Xia and Wang, 1997; Yoshida, 1998) 

or whether it is conspecific with H. cervicornis J. Agardh (e.g., 

Haroun and Prud’homme van Reine, 1993; Xia and Zhang, 

1999). “Hypnea spinella” as reported from Japan (see Yamagishi 

and Masuda, 1997:151, figs. 30–32) and the Hawaiian Islands 

(Mshigeni, 1978a; Abbott, 1999) appears to be a different species. 

Yamagishi and Masuda (2000) concluded that Japanese specimens 

previously referred to “H. spinella” were also different from H. 

cervicornis. Thus, all specimens identified as H. spinella or H. cervicornis are in need of molecular and phylogenetic analyses.

Gulf of California specimens herein referred to Hypnea spinella follow the interpretation of the species by Dawson (1961a). 

C. Agardh (1822) described the thalli of Sphaerococcus spinellus

as being 1.3–2.5 cm long and cartilaginous and rigid, characters 

observed in Gulf specimens. An isotype studied by Cormaci et 

al. (1993) was of similar length and 550 μm in diameter, also in 

agreement with the northern Gulf specimens. Dawson (1961a) 

observed that Hypnea spinella appears to be restricted in distribution to tropical coasts of Pacific Mexico. “Hypnea spinella” 

has also been reported in lagoons along the coast of Sinaloa 

(Piñón-Gimate et al., 2008). 

Hypnea valentiae (Turner) Montagne

Fucus valentiae Turner, 1809:18, pl. 78: figs. a–f. 

Hypnea valentiae (Turner) Montagne, 1841:161; Dawson, 1961a:238, 

pl. 37; 1961b:428; 1966a:24; Norris, 1973:12; Abbott and Hollenberg, 1976:489, fig. 434; Mshigeni and Lorri, 1977:381, figs. 

1–6; Mshigeni, 1978a:878, fig. 15; Huerta-Múzquiz, 1978:338; 

Schnetter and Bula-Meyer, 1982:138, pl. 22: fig. A; Stewart and 

Stewart, 1984:144; Pacheco-Ruíz and Aguilar-Rosas, 1984:77; Norris, 1985d:213; Huerta-Múzquiz and Mendoza-González, 1985:50; 

Mendoza-González and Mateo-Cid, 1986:424; Sánchez-Rodríguez 

et al., 1989:43; Serviere-Zaragoza et al., 1993a:484; Mateo-Cid 

et al., 1993:47; Mendoza-González et al., 1994:107; Womersley, 

1994, figs. 154F, 156A–C; González-González et al., 1996:227; 

Riosmena-Rodríguez et al., 1998:27; Abbott, 1999:119, fig. 25F; 

L. Aguilar-Rosas et al., 2000:131; Cruz-Ayala et al., 2001:191; 

CONANP, 2002:140; Piñón-Gimate et al., 2008:116; Pacheco-Ruíz 

et al., 2008:209; Bernecker and Wehrtmann, 2009:226; CastañedaFernández de Lara et al., 2010:200; Fernández-García et al., 2011:62; 

Pérez-Estrada et al., 2012:191.

Hypnea musciformis var. valentiae (Turner) Harvey, 1834:153.

Hypnea nidifica sensu Dawson, 1944a:290 [in part]; 1959a:25 [non Hypnea 

nidifica J. Agardh, 1852:451]. 

Hypnea esperi sensu Dawson, 1944a:292 [in part]; González-González et al., 

1996:226 [non Hypnea esperi Bory de Saint-Vincent, 1828:157, nom. 

illeg.; see Silva et al., 1996a:298]. 

Thalli of erect, loosely and laxly branched cylindrical axes, 

to 20 cm tall, 0.5–1.5(–2) mm in diameter, gradually reduced in 

diameter upward to acuminate apices; entangled or attached by a 

small discoid holdfast and/or with many secondary discoid holdfasts along lower parts of branched axes. Main axes usually lax 

and irregularly branched, at intervals of 2–8 mm; ultimate branchlets, indeterminate, straight to curved or more or less hook-like; 

axes and branches beset with few to numerous simple to compound spinose determinate branchlets, 0.5–2.0(–5.0) mm long.
NUMBER 96 • 325

Tetrasporangia encircling lower or occasionally middle portion of short, swollen tetrasporangial branchlets. Cystocarps globose or dome shaped, 450–650 μm in diameter, scattered over 

branches. Spermatangia in moderately swollen sori at or near the 

bases of spermatangial branchlets.

Habitat. Growing on rocks or epiphytic or entangled on other algae or invertebrates, particularly gorgonians; also 

reported in coastal lagoons; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena; Bahía de Navachiste to Mazatlán, Sinaloa 

to Jalisco. Eastern Pacific: Santa Barbara, southern California 

to Bahía Magdalena, Baja California Sur; Colima to Guerrero; 

Costa Rica; Colombia; Ecuador; Peru. Central Pacific: Hawaiian 

Islands.

Type Locality. Red Sea.

Remarks. One of the most common species of Hypnea in the Gulf, H. valentiae is reportedly widespread in subtropical and tropical seas.

The taxonomic status of the Gulf of California H. valentiae 

needs further study. For example, the southern California H. californica Kylin (1941; type locality: La Jolla) was considered a synonym of H. valentiae (Dawson, 1961a; Abbott and Hollenberg, 

1976), but others have recognized it as distinct species (e.g., Stout 

and Dreckmann, 1993). Other eastern Pacific species, such as the 

southern California H. valentiae var. gardneri Hollenberg (1972) 

[note: Hollenberg (1972:45, figs. 1–2) also suggested the “Hypneocolax” reported from Bahía Magdalena (Dawson, 1961a: 234, 

pl. 26: fig. 1) were actually reproductive branchlets of H. valentiae 

var. gardneri]. This taxon and those placed in synonymy with the 

Red Sea H. valentiae (Dawson, 1961a), including H. californica

Kylin (1941) and the Isla Guadalupe (Baja California) H. evermannii Setchell et N. L. Gardner (1930), also need to be reexamined and their taxonomic status tested. The southern Gulf of 

California Hypnea marchantae Setchell et N. L. Gardner (1924), 

also reported in southeastern Pacific from Isla Gorgona, Colombia, and Ecuador (Taylor, 1945), was also considered conspecific 

with H. valentiae by Dawson (1944a). However, on the basis of 

their illustrations (Setchell and Gardner, 1924:759, pl. 23: figs. 22, 

23, pl. 42a, pl. 56), H. marchantae appears to be a different species and also needs molecular testing and taxonomic elucidation. 

Yamagishi and Masuda (1997) reported a Hypnea 

charoides-valentiae complex of species in Japan that are in need 

of further clarification. They later concluded on the basis of molecular systematics that the Japanese complex included two species, H. charoides Kützing (1849) and H. flexicaulis Yamagishi et 

Masuda (2000), and presumably does not include H. valentiae.

Hypnea volubilis Searles

Hypnea volubilis Searles in Schneider et Searles, 1976:53, figs. 3–7, 9–10; 

Schneider and Searles, 1991:309, figs. 362–363. 

Algae spreading 5–6 cm; of compressed axes branching 

from the margins; branches spaced irregularly, more or less subdichotomous; branches compressed, 600–750 μm wide, about 

300–375 μm thick (approximately half as thick as wide); ultimate branchlets from less than l to 6 mm long, 160–330 μm 

broad; attached by pads of elongate filaments derived from cortical cells. Central axial cells up to 300(–440) μm long, connected 

to medullary cells by numerous pit connections; no clear distinction between medullary and cortical cells; surface cells isodiametric, 6.0–48 μm in diameter. 

Tetrasporangia zonate, 25–42 μm long, 17–24 μm in diameter; borne in slightly elevated sori mostly surrounding branches 

and branchlets. Gametophytes unknown. 

Habitat. Entangled with other algae and on tidal 

platforms; lowermost intertidal to very shallow subtidal. 

Distribution. Gulf of California: Puerto Peñasco. 

Type Locality. At 23–24 m depths; offshore reef 

(33°30.5′N; 77°24.9′W), R/V Eastwood, Sta. No. 17665 (4 Aug 

1971), North Carolina, USA. 

Remarks. Hypnea volubilis has a very disjunct distribution and was described and reported from very different habitats. In the upper Gulf of California, H. volubilis occurs in the 

lowermost intertidal, whereas the type from North Carolina was 

described from a deepwater offshore reef. It has been reported in 

the western Atlantic from North Carolina, South Carolina, and 

Florida (Schneider and Searles, 1991; Dawes and Matheson, 2008), 

Puerto Rico (Ballantine and Aponte, 1997), and Brazil (Villaca et 

al., 2010). Once Gulf H. volubilis is re-collected, it should be critically compared with the subtidal western Atlantic H. volubilis. 

Dicranemataceae

Dicranemataceae Kylin, 1932:65 [as Dicranemaceae]; Kraft, 1977:223; 

Silva, 1980:82; Kraft and Womersley, 1994:321; Liao et al., 1994:833.

Algae are terete, dichotomously branched, and multiaxial 

in structure. The medulla is wide and composed of thin-walled, 

compacted filaments. Surrounding the medulla is the inner cortical layer of large isodiametric cells and an outer cortex of small 

cells. 

Tetrasporophytes produce zonately divided tetrasporangia. 

Gametophytes are monoecious. The carpogonial branches are 

2- or 3-celled, develop in an outward direction, and lack sterile cells. After fertilization, the diploidized auxiliary cells form a 

small fusion cell that issues multiple gonimoblast initials, and as 

they continue to develop, the gonimoblasts form a web of densely 

compacted small cells that bear the carposporangia. The mature 

cystocarps swelling the fertile branches. Spermatangia are clustered in sunken pits in the outer cortex at the thallus surface. 

Remarks. The Dicranemataceae currently includes 

five genera. The family is represented by one species in the northern Gulf, whose generic status is problematic (Kraft, 1977). 

Dicranema Sonder 

Dicranema Sonder, 1845:56.

Algae are terete, wiry, and repeatedly dichotomously 

branched, with branch internodes that become shorter upward, 

and ultimate branches usually dense. The medulla is a dense 

bundle of compacted filaments. The cortex is two layered, with 

an inner layer of large cells and an outer layer of smaller cells. 
326 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Tetrasporangia are zonately divided, developed within 

prominent nemathecia scattered over the upper axes. Carpogonial branches are two-celled, aggregated around fertile branch 

apices. Carposporophytes are inwardly oriented, and carposporangia are single and terminal on a large mass of compacted cells 

developed from the outer layer of the carposporophyte. Spermatangia are in clusters of separate, sunken pits, clustered in the 

outer cortex. 

Remarks. Carposporophyte development in Dicranema, illustrated by Kraft (1981), is a complex procedure 

that appears to progress in a series of discrete stages that involves much interaction of gametophyte and sporophyte tissue 

(Kraft, 1977). Kraft (1981) regards this unique carposporophyte 

development as arguably the most elaborate and specialized in 

all the red algae. 

One species of Dicranema has been described from the 

northern Gulf of California. 

Dicranema rosaliae Setchell et N. L. Gardner

FIGURE 159

Dicranema rosaliae Setchell et N. L. Gardner, 1924:745, pl. 22: fig. 6; Dawson, 1944a:299; Kylin, 1956:307; Dawson, 1957b:115, figs. 22a, 23a; 

1961a:241, pl. 38: fig. 1; 1961b:430; 1962b:218, fig. 134; 1966a:23; 

Huerta-Múzquiz and Tirado-Lizárraga, 1970:129; Kraft, 1977:233; 

Huerta-Múzquiz, 1978:340; González-González et al., 1996:199; 

CONANP, 2002:139; Pacheco-Ruíz et al., 2008:209; FernándezGarcía et al., 2011:61. 

Algae erect clumps, of slender, terete branches, (125–)250–

450 μm in diameter; more or less dichotomously or irregularly 

branched, almost divaricate near subacute apices; arising directly 

from a small discoid or spreading holdfast. Medulla a small, 

central group of compact, rounded, thin-walled, elongated cells 

surrounded by 2 layers of larger round cells, up to 25 μm in diameter. Inner cortex of small angular cells up to 14 μm in diameter; 

outer cortex a single outer layer of squarish or ellipsoidal cells.

Tetrasporangia and cystocarps unknown for the species. 

Spermatangia in short rows; continuous, covering surface of 

branches. 

Habitat. On rocks and tidal platform, sometimes 

in calm, sandy or muddy habitats; mid to low intertidal; also 

dredged from 4–13 m depths (Dawson, 1961a). 

Distribution. Gulf of California: Puerto Peñasco 

to Topolobampo, Sinaloa; Isla Espíritu Santo. Eastern Pacific: 

Guerrero to Oaxaca; Costa Rica. 

Type Locality. Santa Rosalía, Baja California Sur, 

Gulf of California, Mexico (Dawson, 1961a). Note that the locale was incorrectly stated by Setchell and Gardner (1924:745) 

as “cast ashore, Santa Rosalía, across the bay from Guaymas.” 

Santa Rosalía (east coast of Baja California Sur) is actually 

across the Gulf of California west from Guaymas (coast of Sonora). Today, the Santa Rosalía Ferry offers transport between 

Guaymas and Santa Rosalía.

Remarks. Although most species of Dicranema

are obligate epiphytes on the woody stalks of the sea grass 

Amphibolis C. Agardh (1823), the Gulf of California D. rosaliae

apparently occurs only on rocks. Sporangia or cystocarps of 

Gulf of California Dicranema rosaliae have yet to be found, and 

its taxonomic status remains uncertain. Kraft (1977:233, 235) 

observed similarities in the vegetative transections of Gulf D. 

rosaliae to those of other species of Dicranema but also noted 

its irregular branching pattern and anatomical structure (seen in 

longitudinal sections) were more like those of a Gelidiopsis or 

Wurdemannia Harvey (1853). 

Examination of collections tentatively referred to D. rosaliae from Puerto Peñasco in the upper Gulf revealed superficial 

spermatangia on branches (JN-3263, US Alg. Coll. microscope 

slide 4534), suggesting it is probably dioecious. Thus, it differs 

from Dicranema, which are monoecious and have spermatangia 

in clusters of sunken pits at thallus surface (Kraft and Womersley, 1994). This further supports Kraft’s (1977) suggestion that it 

is probably not a Dicranema. More northern Gulf of California 

collections, particularly the finding of sporophytes and female 

specimens, and molecular DNA testing are needed to elucidate 

the generic status of Gulf D. rosaliae. 

FIGURE 159. Dicranema rosaliae: A. Habit (EYD-10897, US Alg. 

Coll.-7137). B. Transection (after Setchell and Gardner, 1924: pl. 

22: fig. 6). C. Transection showing superficial spermatangia covering branch surface (JN-3263, US Alg. Coll. microscope slide 4534).
NUMBER 96 • 327

Once thought to be a Gulf endemic (Dawson, 1944a), D. rosaliae has since been reported in Costa Rica (Dawson, 1961a) and 

Enewetak Atoll (Eniwetok), Marshall Islands (Dawson, 1957b). 

Records of D. rosaliae from Micronesia (Lobban and Tsuda, 

2003) were later not accepted (Lobban and N’Yeurt, 2006), and 

those from Queensland, Australia, are doubtful (Lewis, 1984).

Dumontiaceae

Dumontiaceae Bory de Saint-Vincent, 1828:197.

Algae are cylindrical to complanate or blade-like. Some 

members are soft and lubricous, others are gelatinous, and 

some are firm. Percurrent main axes are radially to irregularly 

branched. Growth in most is uniaxial, but some are multiaxial. Cortical filaments are developed from whorled laterals and 

branch several times from elongate basal cells; outwardly, the 

cells become smaller and oval to spherical. Cortical filament cells 

lack secondary pit connections.

Tetrasporophytes may be heteromorphic, producing zonately divided tetrasporangia (e.g., Dudresnaya), or isomorphic, 

developing cruciately divided tetrasporangia (e.g., Gibsmithia

Doty, 1963). Nonprocarpic, carpogonial branches of 6–12(–18) 

cells in length, usually with short sterile filaments on lower cells 

of carpogonial branch; carpogonium terminal. Auxiliary cells intercalary in separate branch systems. After fertilization, the carpogonium fuses with 1 or more lower cells of branch, transferring 

diploid nuclei to them from zygote nucleus, and issues connecting 

filaments (tubular connection) that contact successive auxiliary 

cells usually some distance from the carpogonial branch; repeatedly forming gonimoblasts that develop at the junction or from 

cells cut off from auxiliary cells; most gonimoblast cells become 

carposporangia. Spermatangia in clusters on terminal cells. 

Remarks. Some members of the family are known 

to produce antiviral agents, including some that could be used 

for treatment of herpes and other retroviruses (Ehresmann et al., 

1977; Hatch et al., 1979; Neushul, 1990).

The Dumontiaceae is represented in the northern Gulf of 

California by one genus. 

Dudresnaya P. Crouan et H. Crouan

Dudresnaya P. Crouan et H. Crouan, 1835:98.

Algae are erect, soft, mucilaginous, terete to compressed, and 

usually irregularly and repeatedly branched, with the branches 

narrowing in diameter with each branch order. Thalli are uniaxial in structure; the axial filaments may be visible in apical 

regions but is generally obscured below by additional filaments. 

Each axial cell of an axial filament has lateral whorls of (2–)4

(–6) periaxial cells, each of which produces several filaments that 

branch for several orders (forming medulla). Descending rhizoidal filaments are commonly develop from the medullary cells, all 

embedded in a gelatinous matrix. Outermost cortical filaments 

are pigmented. Cells have a single nucleus and ultrastructurally 

possess pit plugs without cap layers.

Life cycles, where known, are triphasic, with isomorphic 

gametophytes and either an isomorphic or heteromorphic tetrasporophyte. Isomorphic tetrasporophytes have zonate tetraspores that are basally attached on the cells of the outer medulla 

or inner cortical filaments. Heteromorphic tetrasporophytes are 

crustose, with cruciately divided tetrasporangia (sometimes irregular cruciate divisions). Gametophytes are monoecious or dioecious. Carpogonial branches are of (5–)10–12(–19) cells. The 

auxiliary cell branch is often long, of 5–20(–43) cells. The auxiliary cell is intercalary and differentiated, usually smaller than 

adjacent cells. After presumed fertilization, the carpogonium divides, contacting and fusing with 1–3 other carpogonial cells. 

Connecting filaments, produced following fusion, contact auxiliary cells on separate branch systems. Gonimoblast initials (2–3) 

are developed at the auxiliary cell of the connecting filaments. 

Cystocarps are immersed within the thallus, with nearly all cells 

developing into small carposporangia. Spermatangia are in clusters; borne either terminal on outer cortical cells or in whorls 

around short, lateral cortical branchlets. 

Remarks. Dudresnaya is usually placed in the Dumontiaceae (Guiry and Guiry, 2011). Phylogenetic studies of 

Tai et al. (2001) and Saunders et al. (2004) found it was closer 

to the Kallymeniaceae. More recently on the basis of molecular 

analysis, D’Archino and Sutherland (2013) included the genus in 

the Dumontiaceae and noted that a multigene phylogeny among 

members of these families would help further elucidate their relationships and familial status. 

One species of Dudresnaya is reported in the northern Gulf 

of California.

Dudresnaya colombiana W. R. Taylor

FIGURE 160

Dudresnaya colombiana W. R. Taylor, 1945:162; Dawson, 1961b:411; 

Norris and Bucher, 1976:8, figs. 7a–c, 8a,b; Mower and Widdowson, 1969:76, fig. 3a–c; Abbott and Hollenberg, 1976:355, fig. 295; 

Eiseman and Norris, 1981:187; Schnetter and Bula-Meyer, 1982:121, 

191, pl. 15: fig. F; Bula-Meyer, 1995:35; González-González et al., 

1996:199; L. Aguilar-Rosas et al., 2000:130; Pacheco-Ruíz et al., 

2008:207; Fernández-García et al., 2011:61.

Algae soft and gelatinous, translucent pink to rose, up to 

7(–14) cm high. Axes 3–5(–10) mm broad, terete to slightly 

compressed, variously branched above a short stipe. Irregularly 

branched to 2–4 orders, with many delicate ultimate branches. 

Branches narrowing with successive orders; ultimate branchlets 

shortest, usually with acute apices. Internally, the axial filament 

cells bearing lateral whorl of periaxial cells, each of these issues 

several branched filaments, the outermost layers form the cortex. 

Axial filament cells 7–16(–20) μm in diameter, whereas broader 

older axes often with wider axial filament cells (45–70 μm in 

diameter). Slender descending rhizoidal filaments (2 μm in diameter) develop from medullary cells. The assimilatory branchlets 

branch dichotomously and gradually taper distally. Cortical cells 

cylindrical, becoming shorter and ovoid toward the thallus surface, with ultimate cells 5–8 μm long and to 4 μm in diameter.
328 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Tetrasporophytes not known in Gulf of California. Gametophytes dioecious. Auxiliary cell branch is a single series of 8–17 

round cells. Cystocarps subspherical, 120–180 μm in diameter; 

borne on an auxiliary cell, usually the third cell from the base of 

the auxiliary cell filament. Spermatangia clustered terminally on 

the outer cells of cortical filaments.

Habitat. On rocks; low intertidal to subtidal, 15–22 m 

depths. 

Distribution. Gulf of California: Santa Teresa 

(Baja California); Isla Mejía and Isla Estanque (Islas de la Cintura). Eastern Pacific: Santa Catalina Island (California Channel 

Islands); Colombia. 

Type Locality. Intertidal; Isla Gorgona (Parque 

Nacional Natural Isla Gorgona), Departamento de Valle del 

Cauca, Pacific Colombia.

Remarks. Apparently rare in the northern Gulf, Dudresnaya colombiana was collected in the subtidal from two of 

the Midriff Islands in spring (April) (Norris and Bucher, 1976) 

and, more recently, in the upper Gulf from the northeast coast of 

Baja California (L. Aguilar-Rosas et al., 2000) in intertidal shallow water during autumn and winter. 

Gigartinaceae*

Gigartinaceae Bory de Saint-Vincent, 1828:149.

The Gigartinaceae contains algae that have erect, simple 

or branched, cylindrical, compressed or blade-like thalli. Many 

are firm and fleshy and bear soft spines (spinous outgrowths) or 

proliferations marginally or on surfaces; others may be smooth. 

Growth is multiaxial. Internally, the medulla is a network of 

interwoven, branched, filiform filaments, and the cortex consists 

of anticlinally branched rows of progressively smaller cells toward the outer pigmented surface layer. Cortical filament cells 

have secondary pit connections. 

Tetrasporangia are cruciately divided and form short rows or 

globose masses internally or are in round to elliptical sori. The 

tetrasporangia are scattered over the thallus surface or associated 

with spinose projections or papillae. Cystocarps are embedded 

within the thallus and either project from its surface on one side or 

* Contributed by James N. Norris and Suzanne Fredericq. S. Fredericq: 

Department of Biology, University of Louisiana at Lafayette, 

Lafayette, Louisiana 70504, USA.

FIGURE 160. Dudresnaya colombiana: A. Habit (JN-5480, US Alg. Coll.-8760). B. Spermatangia at tips of cortical filaments (JN-5680, US Alg. 

Coll. microscope slide-3767). C. Mature carposporophyte on auxiliary cell (arrow) filament (JN-5480, US Alg. Coll. microscope slide 3769). 
NUMBER 96 • 329

are associated with spinose outgrowths. The female reproductive 

apparatus is a procarp, consisting of a three-celled carpogonial filament with its supporting cell lacking sterile filaments. The carpogonium fuses with the supporting cell of the carpogonial branch after 

fertilization, and the supporting cells thus becomes the auxiliary 

cell. The gonimoblast filaments develop toward the interior of the 

thallus, with nearly all cells developing into carposporangia. Spermatangia are in shallow sori or on the surface of the thallus.

There are two genera of the Gigartinaceae in the northern 

Gulf of California.

KEY TO THE GENERA OF GIGARTINACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Cystocarps globose, prominent above the thallus surface or in spinose laterals along margins . . . . . . . Chondracanthus

1b. Cystocarps embedded within inner cortex connected to medulla filaments and protruding above both thallus surface 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mazzaella

Chondracanthus Kützing

Chondracanthus Kützing, 1843:399.

Algae are erect, with one or more cylindrical, compressed, 

or foliose fronds, which arise from a discoid or peg-like holdfast. 

Fronds are entire, dichotomously or pinnately branched, or irregularly divided. The surface generally has papillae or spinose 

outgrowths, but in some it may be smooth. The medulla is composed of colorless interwoven, anastomosing filaments. The cortex consists of anticlinally branched rows of small cells. 

Tetrasporangia are in globose to irregularly shaped sori organized in the inner cortex. Tetrasporangia are cruciately divided, 

transformed exclusively from cells in primary filaments within the 

cortex, and released through pores in the outer wall. Cystocarps 

are globose, with an ostiolate pericarp, and protrude from the 

frond surface or may be borne laterally along the upper axes and 

branch margins. Functional auxiliary cells form a few inwardly 

directed protrusions that bear gonimoblast initials, surrounded 

by a conspicuous persisting envelope composed of secondary 

filaments. Gonimoblast filaments penetrate between cells of the 

envelope, linking to them by secondary pit connections with the 

formation of heterokaryotic cells. Carposporangial chains are 

derived entirely from the gonimoblast filaments, often separated 

by large sterile cells that are not organized into a network. Spermatangia are in irregularly shaped sori on the frond surface. They 

form short, dense rows terminating on the cortical cells. 

There are five species known in the northern Gulf of 

California.

KEY TO THE SPECIES OF CHONDRACANTHUS IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli entangled, forming clumps or irregularly shaped mats; branches slender to narrow, terete or compressed, with 

smooth surfaces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Thalli mostly free (not tightly clumped), semierect to erect; of compressed to flattened, narrow to wide branches; surfaces 

smooth or with spinose proliferations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2a. Branches terete, wire-like, 0.5–0.75 mm in diameter; in irregular mats . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. acicularis

2b. Branches compressed to flattened, 1.0–2.0 mm wide, repent, recurved, densely overlapping; in low growing clumps 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . “C. intermedius”

3a. Branches narrow, 0.5–1.0 mm in diameter; upper portions freely branched; with spinose branchlets . . . . . . . C. tepidus

3b. Branches over 2.0 mm wide, up to 12 mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Axes and branches narrow, mostly 2–4 mm wide, with smooth surfaces; occasionally with short subterete laterals . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. zertuchei

4b. Axes and branches mostly over 4 mm wide; 4–12 mm in width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 

5a. Axes and branches usually less than 6 mm wide; surfaces beset with very short, branched spines throughout . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. squarrulosus (in part)

5b. Main axes and branches wider, over 6 mm, up to 12 mm in width; surfaces smooth or partially to entirely covered with 

spinose outgrowths . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

6a. Blade surface smooth to partly covered; surface usually with spinose outgrowths in between smooth (lacking spines), 

distinct, narrow intramarginal zones . . . . . . . . . . . . . . . . . . . . . . . C. squarrulosus (in part, formerly “C. johnstonii”)

6b. Blade surface with spinose outgrowths usually covering entire surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. squarrulosus (in part, formerly “C. macdougalii”)

Chondracanthus acicularis (Roth) Fredericq

FIGURE 161

Ceramium aciculare Roth, 1806:114, nom. nov. (see Silva et al., 1996a: 

290).

Chondracanthus acicularis (Roth) Fredericq in Hommersand et al., 1993:117 

[as “C. acicularis (Wulfen) Fredericq”]; Silva et al., 1996a:290; Abbott, 1999:131, fig. 31A–D; Pacheco-Ruíz and Zertuche-González, 

2002:467; Pacheco-Ruíz et al., 2008:209. 
330 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Gigartina acicularis (Roth) J. V. Lamouroux, 1813:44; Dawson, 1966a:24; 

1966b:64, fig. 4B; González-González et al., 1996:313.

Fucus acicularis Wulfen, 1803:63, nom. illeg. [non Fucus acicularis Esper, 

1800:172, pl. XCI: figs. 1–2]. 

Algae entangled, forming irregularly shaped, low-lying 

clumps (occasionally solitary), up to 10 cm tall; of cartilaginous, slender, terete (sometimes slightly compressed), irregularly 

branched axes, 500–750 μm (to 1.0 mm) in diameter; reddish 

green to purplish green; repent axes below attached by small 

holdfasts. Branches slightly attenuated near branch origin and 

upward toward apex.

Tetrasporangia in irregularly shaped sori. Cystocarpic and 

spermatangial not seen in Gulf of California specimens. 

Habitat. Occasional, on rocks; mid to low 

intertidal. 

Distribution. Gulf of California: Punta Pelícano, 

Playa Arenosa, and Playa Las Conches (Playa Estación; vicinity 

of Puerto Peñasco) to Puerto Lobos; Bahía de Los Ángeles. Central Pacific: Hawaiian Islands. 

Type Locality. “In variis submarinis corporibus” 

(Wulfen, 1803:63). Lectotype locality: Adriatic Sea (Dixon and 

Irvine, 1977b:237). 

Remarks. Chondracanthus acicularis was first reported in the upper Gulf of California by Dawson (1966a, 

1966b, as “Gigartina acicularis”). The Gulf material is tentatively referred to this species and should be critically compared 

with the European type locality C. acicularis.

Chondracanthus intermedius (Suringar) Hommersand

Gigartina intermedia Suringar, 1868:259; Suringar, 1870:30, pl. 17B; 

Okamura, 1908:172, pl. 35: figs. 1–5; Dawson, 1961a:268 [in 

part; description only, not pl. 54: fig. 2]; Mikami, 1965:205, fig. 14; 

Mendoza-González and Mateo-Cid 1985:28; Mendoza-González et 

al., 1994:107; Fernández-García et al., 2011:62. 

Chondracanthus intermedius (Suringar) Hommersand in Hommersand 

et al., 1993:115; Mateo-Cid et al., 2000:65; L. Aguilar-Rosas et al., 

2000:131; Pacheco-Ruíz and Zertuche-González, 2002:467; PachecoRuíz et al., 2008:209; Hughey and Hommersand, 2008:152 [in part; 

description only]. 

Algae forming low-growing clumps, 2–3 cm high, spreading 

over substratum, purplish red to black with a bluish iridescence; 

of densely overlapping, compressed to flattened, branched cartilaginous axes; firmly attached where branches contact substratum. 

Axes arising from repent axes, 1–2 mm wide; irregularly branched; 

branches 8–12 mm long, mostly 0.5–1.5 mm (sometimes to 2 mm 

or more) in diameter, often adhering to each other by secondary 

attachments, often with short spinose laterals; upward branches 

becoming sublanceolate, recurved, with acute apices.

Tetrasporangia not seen in Gulf material. Cystocarps subglobose, about 1 mm in diameter; sessile, on margins of axes and 

branches. Spermatangia not seen.

Habitat. On rocks and tidal platform; low intertidal.

Distribution. Gulf of California: Santa Teresa to 

Puertecitos (L. Aguilar-Rosas et al., 2000); Playa Los Algodones, northwest of San Carlos (Hughey and Hommersand, 2008); 

Cabo Pulmo (Mateo-Cid et al., 2000); Mazatlán (MendozaGonzález et al., 1994). Eastern Pacific: El Salvador; Islas Juan 

Fernández, Isla San Ambrosio, and Isla San Félix, Chile (Ramírez 

et al., 1994; Silva and Chacana, 2005). Western Pacific: China 

(Tseng, 1983; Xia and Zhang, 1999); Japan (Yoshida, 1998); 

Vietnam (Tsutsui et al., 2005).

Type Locality. Sea of Japan (East Sea), west coast 

of Japan.

Remarks. Some northern Gulf of California specimens are tentatively referred to “Chondracanthus intermedius.” 

Dawson (1961a:268, as “G. intermedia”) based his identification of the Gulf of California specimens on the interpretation of 

“Japanese Gigartina intermedia” by Okamura (1908:172, pl. 35: 

figs. 1–5), but his collections may have included more than one 

species. Later, Abbott (1998, 1999) concluded that the Japanese 

G. intermedia Suringar (1870:29) was a taxonomic synonym of 

Chondracanthus tenellus (Harvey) Hommersand (in Hommersand et al., 1993; basionym: Gigartina tenella Harvey, 1860; 

Dawson, 1959b:22) and that Okamura’s (1908) material identified as “G. intermedia” represented a different species, which 

she described as Chondracanthus okamurae I. A. Abbott (1998). 

On the basis of morphological and molecular studies, the 

phylogenetic analyses of Hughey and Hommersand (2008: figs. 

1, 2) showed their specimens of Japanese C. intermedius and 

northern Gulf of California material were close to each other, 

but both were different from C. tenellus. They concluded C. intermedius (Suringar) Hommersand is a western Pacific species 

and that their Gulf of California specimens from Playa Los Algodones (Sonora) should be tentatively referred to as C. intermedius. Therefore, the taxonomic status of the Gulf of California 

“C. intermedius” needs to be tested and compared with type 

FIGURE 161. Chondracanthus acicularis: Habit (EYD-27263, US 

Alg. Coll.-40576).
NUMBER 96 • 331

materials of Gigartina intermedia Surignar (1868, 1870) and 

C. okamurae I. A. Abbott (=“G. intermedia” sensu Okamura, 

1908, 1936). This will help elucidate the taxonomic status of 

Sonoran Gulf coast “C. intermedius” and clarify the status of C. 

okamurae from Japan. 

There appears to be more than one species among the Gulf 

specimens of “C. intermedius” as interpreted by Dawson (1961a). 

There are two morphologies, which can be separated by habit, 

color, and size. The Gulf of California C. intermedius (sensu 

Hughey and Hommersand, 2008) is characterized by a low pulvinate habit of dense, overlapping, cartilaginous, compressed to 

flattened axes and branches, 1–2 mm in diameter, and purplish red 

to blackish in color. The second Gulf morphology differs in being 

semierect (not in dense clumps), taller, up to 4 cm, with wider, flattened axes, 2–4 mm in width, and greenish red to brownish red in 

color (cf. Dawson, 1961a: pl. 54: fig. 2). The latter is proposed to 

be a new species, Gulf C. zertuchei (described herein).

Chondracanthus squarrulosus (Setchell et N. L. Gardner) 

Hughey, P. C. Silva et Hommersand 

FIGURE 162

Grateloupia? squarrulosa Setchell et N. L. Gardner, 1924:780 [with a generic 

query], pls. 81, 82 [type specimen]; Dawson, 1944a:281; 1954c:258; 

1961b:422; 1966a:25; Littler and Littler, 1981:153; Stewart, 1982:84; 

González-González et al., 1996:219; CONANP, 2002:140; PachecoRuíz and Zertuche-González, 2002:467; Mateo-Cid et al., 2006:51. 

Chondracanthus squarrulosus (Setchell et N. L. Gardner) Hughey, P. C. Silva 

et Hommersand, 2001:1105; Pacheco-Ruíz et al., 2005a:629, figs. 

2–10; Hughey and Hommersand, 2008:141, figs. 28 [type], 29–31; 

Pacheco-Ruíz et al., 2008:209; Pacheco-Ruíz et al., 2011:127.

Gigartina chauviniisensu Setchell and Gardner, 1924:744. pl. 46: fig. b, pl. 70 

[non Gigartina chauvinii (Bory de Saint-Vincent) J. Agardh, 1842:104; 

basionym: Sphaerococcus chauvinii Bory de Saint-Vincent, 1828:165, 

which is now Chondracanthus chauvinii (Bory de Saint-Vincent) Kützing, 1843:399].

Gigartina johnstonii E. Y. Dawson, 1944a:302; 1950d:339, fig. 3; 

1961a:269, pl. 57; 1961b:432; 1966a:24; West and Guiry, 1982:205, 

figs. 1–24; McCandless et al., 1983:177, 180; Norris, 1985d:212, fig. 

16.5; González-González et al., 1996:210.

Chondracanthus johnstonii (E. Y. Dawson) Guiry in Hommersand et al., 

1993:115; L. Aguilar-Rosas et al., 2000:131; Mateo-Cid et al., 2006:56; 

Pacheco-Ruíz et al., 2008:209.

Gigartina macdougalii E. Y. Dawson, 1944a:303, pl. 64: fig. 2; 1950d:338, 

fig. 4; 1961a:271, pl. 58: fig. 2; 1961b:433; Norris, 1973:14; HuertaMúzquiz, 1978:337; González-González et al., 1996:210; PachecoRuíz and Zertuche-González, 2002:467; Pacheco-Ruíz et al., 2008:209. 

Chondracanthus macdougalii (E. Y. Dawson) Guiry in Hommersand et al., 

1993:115; L. Aguilar-Rosas et al., 2000:131.

Gigartina papillata sensu Norris, 1973:14; Pacheco-Ruíz et al., 2008:209 

[non Gigartina papillata (C. Agardh) J. Agardh, 1846: pl. 19, basionym: Sphaerococcus papillatus C. Agardh, 1821: pl. 19, which is now

Mastocarpus papillatus (C. Agardh) Kützing, 1843:298].

Gigartina pectinata E. Y. Dawson, 1944a:302, pl. 64: fig.1 (holotype); 

1950a:339, fig. 6; 1961a:273, pl. 61: fig. 1; 1961b:433; Norris, 

1973:14; Huerta-Múzquiz, 1978:337; Norris, 1985d:212; Barilotti and 

Zertuche-González, 1990:35; Pacheco-Ruíz et al., 1992:263; GonzálezGonzález et al., 1996:211. 

Chondracanthus pectinatus (E. Y. Dawson) L. Aguilar-Rosas et R. AguilarRosas, 1997:155, figs. 1–7; Pacheco-Ruíz and Zertuche-González, 

1999:159; L. Aguilar-Rosas et al., 2000:131; L. Aguilar-Rosas et al., 

2002:234; Pacheco-Ruíz and Zertuche-González, 2002:467. 

Grateloupia johnstonii Setchell et N. L. Gardner, 1924:782, pl. 84; Dawson, 

1944a:281; 1954c:259 [with a generic query]; 1961b:422; GonzálezGonzález et al., 1996:218. 

Algae greenish red, reddish brown to dark purple-red, cartilaginous, up to 40 cm tall, of branched ligulate blades, (3–)5–

15(–20) mm wide; sparsely to repeatedly pinnately to irregularly 

branched to (2–)4–6(–8) orders; attached initially by discoid 

holdfast, later by development of entangled, branched stoloniferous growths; also attached by secondary accessory discs from 

elongated outgrowths on underside of blade surfaces and branch 

apices. Secondary attachment discs may also grow new thalli. 

Axes’ and branches’ surfaces may be smooth, or with surfaces 

and margins partially smooth to entirely covered by short spinose outgrowths or simple to divided proliferations, 5.0–270 

mm long (blades sometimes with a limited intramarginal zone 

without spinose outgrowths). Medulla of filiform filaments, variable in size and shape, sometimes vacuolated, (4–)10–30 μm in 

diameter. Cortex of 4–6 layers; inner cortical cells inflated 20–30 

μm in diameter with prominent interstices; outward giving rise 

to rows of 4–5 small outer cortical cells.

Tetrasporangia aggregated in small sori and embedded near 

the bases of marginal and surface spinulose outgrowths or proliferations. Cystocarps globose, 300–500 μm in diameter, borne on 

or partly associated with spinulose outgrowths, scattered over 

marginal and surface outgrowths. Spermatangia in small sori, 

scattered over blade surface and spines.

Habitat. On rocks, shells, or other hard substratum, 

in crevices, and in tide pools; sometimes entangled with other 

algae or sometimes unattached and freely floating; mid to low 

intertidal, occasionally in shallow subtidal. 

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Bahía Bocochibampo (vicinity of 

Guaymas); Isla Ángel de la Guarda to Isla San Esteban (Islas de 

la Cintura); San Felipe to Puertecitos; Isla Coronado and La Sílica, Bahía de Los Ángeles to Bahía San Francisquito (Baja California); Bahía de Loreto. 

Type Locality. Isla Coronado (Isla Smith), north of 

Bahía de Los Ángeles, Baja California, Gulf of California, Mexico. 

Remarks. Dawson (1961a:273) noted specimens 

of “Gigartina pectinata” showed “puzzling intergrades toward 

those of G. johnstonii.” More recently, on the basis of genetic 

evidence from the analysis of type material, Hughey et al. (2001) 

and Hughey and Hommersand (2008) showed that five Gulf of 

California species, Gigartina johnstonii, Gigartina pectinata, 

Gigartina macdougalii, Grateloupia? johnstonii, and Grateloupia? squarrulosa, were all one species, i.e., Chondracanthus 

squarrulosus.
332 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 162. Chondracanthus squarrulosus: Several thalli showing morphological variability. A. Habit (JN-3690, US Alg. Coll.-159405). 

B. Habit (JN-3690, US Alg. Coll.-159404). C. Habit (previously “Gigartina macdougali”) (JN-3298, US Alg. Coll.-159444). D, E. Portions of 

two thalli (previously “G. pectinata”) (D, JN-3026, US Alg. Coll.-159487; E, JN-2982, US Alg. Coll.-159463).
NUMBER 96 • 333

Chondracanthus squarrulosus is currently recognized as a 

phenotypically highly variable species, exhibiting a wide range 

of size, shape, color, degree of branching, and surface characteristics that were once considered of taxonomic value. In fact, 

the taxa that are now synonyms were separated primarily on 

the basis of these characters. For example, surfaces on blades 

of some specimens are entirely lacking outgrowths on tetrasporangial blades, others may be partially smooth and partly 

covered or entirely covered, and some have surfaces partly lacking spinose outgrowths only within a distinct intramarginal 

zone. The growth and biomass of C. squarrulosus is greatest in spring (Pacheco-Ruíz and Zertuche-González, 1999, as 

“C. pectinatus”).

Chondracanthus tepidus (Hollenberg) Guiry

FIGURE 163

Gigartina tepida Hollenberg, 1945:449, fig. 5; Dawson, 1950d:339; 

1959a:26; 1961a:275, pl. 58: fig. 1; 1961b:433; 1966a:25; Abbott and 

North, 1972:75; Norris, 1973:14; Abbott and Hollenberg, 1976:527, 

fig. 472; Huerta-Múzquiz, 1978:336; Mendoza-González and MateoCid, 1985:28; Mendoza-González and Mateo-Cid, 1986:424; SánchezRodríguez et al., 1989:44; Stewart, 1991:112; González-González et 

al., 1996:211. 

Chondracanthus tepidus (Hollenberg) Guiry in Hommersand et al., 

1993:115; L. Aguilar-Rosas et al., 2000:131; Pacheco-Ruíz and 

Zertuche-González, 2002:467; Hughey and Hommersand, 2008:145, 

fig. 37 [holotype]; Pacheco-Ruíz et al., 2008:209. 

Gigartina teedii sensu Dawson, 1944a:301 [non Gigartina teedii (Mertens ex 

Roth) J. V. Lamouroux, 1813:137; =Chondracanthus teedei (Metens ex 

Roth) Kützing, 1843:399]. 

Algae usually in clumps of irregularly, distichously branched 

thalli, with or without a distinct main axis, usually more or less 

pinnately to irregularly branched, up to 5 cm tall; attached below 

by accessory discs on bladelet apices. Branches subcylindrical to 

flattened, 0.5–2.0 mm wide, with several distichous ultimate 

branchlets, 1.0–5.0 mm in length, surfaces usually smooth; with 

acute apices.

Tetrasporangia in small superficial sori, mostly marginal 

on branches and upper branchlets. Cystocarps globose, about 

500 μm in diameter, mostly on branch margins. Spermatangia in 

small sori, on branchlets. 

Habitat. On rocks and shells in sandy areas of tidal 

flats, in sheltered, shallow waters of bays and estuaries, and occasionally in semiexposed habitats on rocks, tidal platforms, and 

in tide pools; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas; El Coloradito to Islas de Los Gemelos (Bahía de 

Los Ángeles); Sinaloa. Eastern Pacific: northern Washington 

to San Diego, southern California (Hughey and Hommersand, 

2008); San Quintín, Baja California to Bahía Tortugas (inside 

southeast Bahía San Bartolomé), Baja California Sur (MendozaGonzález and Mateo-Cid, 1985).

Type Locality. Balboa, upper Newport Bay, Orange County, southern California, USA.

Remarks. The northern Gulf of California Chondracanthus tepidus is an intertidal species reported from semiexposed 

habitats and shallow waters of protected bays and estuaries (note 

the deep subtidal records, reportedly dredged from 60–80 m depths 

off Bahía San Luis Gonzága [Dawson, 1961a:276]; the depths need 

to be verified by collection of attached growing specimens).

Hughey and Hommersand (2008:145) did not include records of C. tepidus from the Gulf of California or Pacific Baja 

California in their distribution list. Thus, Gulf specimens in 

general morphological agreement are tentatively referred to as 

C. tepidus until the taxonomic status of Gulf specimens can be 

tested by molecular comparisons.

Chondracanthus zertuchei J. N. Norris et Fredericq, sp. nov.

FIGURE 164

Gigartina intermedia sensu Dawson, 1959a:26; 1961a:268 [in part; only 

Gulf of California specimen on pl. 54: fig. 2]; 1966a:24; 1966b:64; 

González-González et al., 1996:210 [non Gigartina intermedia Suringar, 1868:259; Suringar, 1870:30, pl. 17B, which now is

FIGURE 163. Chondracanthus tepidus: A. Habit of clump. B. 

Branch separated from clump showing branching patterns (A, B, 

JN-5451, US Alg. Coll.-159488).
334 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Chondracanthus intermedius (Suringar) Hommersand in Hommersand et al., 1993:115].

Chondracanthus intermedius sensu Hughey and Hommersand, 2008:153, 

fig. 67 [in part; only the Gulf of California material of Dawson, 1961a; 

non Chondracanthus intermedius (Suringar) Hommersand in Hommersand et al., 1993:115].

Latin Description. Thalli formantes caespites 

humiles axium ramosorum, usque ad 4.0 cm alti, atroviridisanguinei usque ad atropurpurei, semicartilaginosi; thallus infimus ramorum repentium compressorum, pro parte maxima 

5–12 mm longa, 1.0–1.5 mm latus affixus per haptera discoidea 

ubi rami inferni contigui substratum. Rami superni formati repentibus infimis ramis; compressi, recurvati, semi-erecti vel repentes, 2–4 cm long., (1.0–)2.0–3.0(–4.0) mm lat.; irregulariter 

ramosi, 2–4 ordinum; plerumque aliquot sublanceolatis, curtis lateralibus ramulis (restrictis ad margines), acutis apicibus; 

ultimi ramuli subteretes, usque ad 1.0 cm long, fere 0.5 mm 

diametro.

Tetrasporangia ignota. Cystocarpia globulosa, cornata, 

usque ad 1 mm diametro, nata secus laminae margines. Spermatangia non visa.

Algae forming low-growing tufts of branched axes, up to 

4.0 cm tall; dark greenish red to purplish red, semicartilaginous; 

lowermost thallus of repent, compressed branches, mostly 5–12 

mm long,1.0–1.5 mm wide; attached by discoid holdfasts where 

lower branches contact substratum. Upper branches developed 

from repent lowermost branches; compressed, recurving, semierect 

or repent, 2–4 cm long, (1.0–)2.0–3.0(–4.0) mm wide; irregularly 

branched, 2–4 orders; usually with few sublanceolate, short lateral 

branchlets (restricted to margins), with acute apices; ultimate 

branchlets, subterete, up to 1.0 cm long, about 0.5 mm in diameter.

Tetrasporangia unknown. Cystocarps globular, cornate, up 

to 1 mm in diameter, borne along blade margins. Spermatangia 

not seen.

Habitat. On rocks and tidal platforms; mid to low 

intertidal. 

Distribution. Gulf of California: Puerto Peñasco 

to Bahía San Francisquito; Isla Las Ánimas (Isla San Lorenzo del 

Norte), southwestern Islas de la Cintura. 

Type Specimen. 24 May 1972, Coll. J. N. Norris, 

JN-3227 (holotype: US Alg. Coll.-159436).

Type Locality. Bahía San Francisquito, Baja California, Gulf of California, Mexico. 

Etymology. Chondracanthus zertuchei is named 

for José Antonio Zertuche-González (Professor, Facultad de 

Ciencias Marinas, Instituto de Investigaciones Oceanológicas, 

Universidad Autónoma de Baja California, Ensenada) in recognition of his contributions to our knowledge on the biology, uses, 

and cultivation of the economic species of marine algae, particularly those of the Gulf of California and Pacific Baja California.

Remarks. The Gulf material referred to “Chondracanthus intermedius” sensu Dawson (1961a) included more 

than one species. Herein one is recognized as a new species, 

C. zertuchei. This new species also includes the Gulf specimen 

of Dawson (1961a: pl. 54: fig. 2, as “Gigartina intermedia”). 

Chondracanthus zertuchei differs from C. intermedius, which 

forms clumps of entangled, repent, flattened narrow axes that 

are 1–2 mm wide and 0.5–1.0 mm wide branches that have short 

spinose laterals (Hommersand et al., 1993; Hughey and Hommersand, 2008), and from C. okamurae I. A. Abbott (1998), 

which has subcylindrical repent axes that are 170–320 μm in 

diameter (see Remarks under C. intermedius).

Uncertain Record:

Chondracanthus canaliculatus (Harvey) Guiry

Gigartina canaliculata Harvey, 1841:409.

Chondracanthus canaliculatus (Harvey) Guiry in Hommersand, Guiry, Fredericq and Leister, 1993:115.

Remarks. Recorded with a taxonomic query from 

Segundo Cerro Prieto, Bahía Kino, Sonora, by MendozaGonzález and Mateo-Cid (1986, as “Gigartina canaliculata?”), 

it is a doubtful record, and the specimens should be reexamined.

Mazzaella G. De Toni 

Mazzaella G. De Toni, 1936b:[4].

Algae are erect, with one or more compressed to flattened 

blades. Blades may be simple, irregularly divided, or dichotomously branched and arise directly from a small stipe above 

the basal holdfast. The medulla is composed of colorless, interwoven longitudinal filiform filaments. The cortex consists of 

anticlinally branched rows of progressively smaller cells toward 

the surface. 

FIGURE 164. Chondracanthus zertuchei: Holotype (JN-3227, US 

Alg. Coll.-159436).
NUMBER 96 • 335

Tetrasporangia are cruciately divided and situated in circular to elliptical sori in the inner cortex or outer medulla within 

the blade; they are borne in branched chains transformed from 

cells in primary cortical filaments or secondary lateral filaments 

cut off from cortical or medullary cells and linked to other 

cells by secondary pit connections. Cystocarps are globose, 

with or without an ostiole, embedded deeply in the blade, and 

scattered over thallus surface, or borne in spinose projections. 

Functional auxiliary cells form numerous lateral and inwardly 

directed protrusions bearing gonimoblast initials that are not 

surrounded by an envelope. The gonimoblast filaments are 

compact and short celled and displace the filiform primary and 

secondary medullary filaments, often linking them via terminal 

tubular cells. Inner gonimoblast cells expand, becoming broad. 

Carposporangia are borne in chains. Spermatangia are in sori, 

on the blade surface.

There are three species that were described from the northern Gulf of California.

KEY TO THE SPECIES OF MAZZAELLA IN THE NORTHERN GULF OF CALIFORNIA

1a. Blades 10–20 cm tall, broadly expanded, 5–8(–12) cm wide, usually more or less dichotomously divided, with acute 

tips . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. hancockii

1b. Thalli palmately divided or strap-like; shorter, mostly 4–6 cm tall; much narrower, less than 1.0 cm wide . . . . . . . . . . 2

2a. Fronds palmate, usually less than 4 cm tall, 5–9 mm wide; dichotomously divided 2–4 times; ultimate apices acute or 

blunt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. digitata

2b. Fronds strap-like, up to 6 cm tall; much narrower, 1.5–2.5 mm in width; irregularly branched, sometimes more or less 

subdichotomously; segments with acute apices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . M. diffusa

Mazzaella diffusa (E. Y. Dawson) J. N. Norris et Fredericq, 

comb. nov.

FIGURE 165

Rhodoglossum diffusum E. Y. Dawson, 1961a:257, pl. 49: fig. 3; 1961b:434; 

González-González et al., 1996:265; Pacheco-Ruíz and ZertucheGonzález, 2002:467; Pacheco-Ruíz et al., 2008:209. 

Gigartina diffusa (E. Y. Dawson) D.-H. Kim, 1976:44. 

Algae of a few erect, narrow, strap-like axes, up to 6 cm 

high and 1.5–2.5 mm wide, irregularly, diffusely branched; 

above a common discoid holdfast. Flattened axes irregularly 

subdichotomously branched at 3–17 mm intervals, often broadening upward, and tapering to branch origin; older fronds sometimes with few pinnate branchlets; ultimate branches with acute 

to rounded apices. Upper portions, 170–250 μm thick. Medulla 

dense, of slender filiform filaments. Cortex of inner cortical cells, 

decreasing in size to outer cortical layer of small, pigmented cells 

in anticlinal rows; outermost layer of elongated cells.

Tetrasporangia not seen. Cystocarps ellipsoidal, 600–900 

μm in diameter; embedded in medulla and bulging equally on 

both blade surfaces; scattered throughout middle to upper portions of blades. Spermatangia not seen. 

Habitat. On rocks, low intertidal to subtidal, down 

to 17 m depths. 

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda; Isla La Ventana, offshore of Bahía de 

Los Ángeles. 

FIGURE 165. (Right) Mazzaella diffusa: A. Habit (JN-2999, US 

Alg. Coll.-160802). B. Transection of thallus (JN-2999, US Alg. 

Coll. microscope slide 5340).
336 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Type Locality. Intertidal rocky shore; Puerto Refugio, Isla Ángel de la Guarda (Islas de la Cintura), Gulf of California, Mexico. 

Remarks. Endemic to the northern Gulf of California, Mazzaella diffusa was previously known only from one island of Islas de la Cintura and is now reported off the central 

Gulf coast of Baja California from Isla La Ventana (JN-2999, 

US Alg. Coll.). Although these subtidal specimens are in general 

agreement with M. diffusa, they differ in having mostly rounded 

to blunt apices and lack marginal laterals (Figure 165A) compared to the intertidal type of Dawson (1961a: pl. 47: fig. 3).

Dawson (1961a:258, as “Rhodoglossum diffusum”) suggested M. diffusa may have been remotely derived from the 

M. affinis complex. An eastern Pacific species, the Monterey, 

California, M. affinis (Harvey) Fredericq (in Hommersand et al., 

1993; basionym: Chondrus affinis Harvey, 1841:408) is known 

from Alaska to Baja California (Abbott and Hollenberg, 1976; 

Scagel et al., 1989; Stewart, 1991) and Chile (Ramírez, 1982; 

Ramírez and Santelices, 1991). Further collections of Gulf of 

California M. diffusa are needed to test Dawson’s hypothesis of 

its origin and possible phylogenetic relationship to M. affinis. 

Mazzaella digitata (E. Y. Dawson) J. N. Norris et Fredericq, 

comb. nov.

FIGURE 166

Rhodoglossum digitatum E. Y. Dawson, 1961a:258, pl. 45: fig. 3; 1961b:434; 

González-González et al., 1996:265; Pacheco-Ruíz et al., 2008:209. 

Gigartina digitata (E. Y. Dawson) D.-H. Kim, 1976:44, 92.

Algae of a few, erect, flattened, palmately divided blades, up 

to 3.5 cm high, arising from a short, terete stipe, 1–3 mm long; 

attached below by a small common discoid holdfast. Blades 2–4 

times dichotomously to subdichotomously divided; widening 

upward above stipe region, 6–16 mm long and 5–9 mm wide; 

ultimate divisions divaricate, short, terminally blunt or acute.

Tetrasporangial sori irregularly shaped masses, 400–1000 

μm in diameter; scattered in upper portions of blades; tetrasporangia embedded in medulla and inner cortex. Cystocarps elliptical, 0.9–2.0 mm in diameter, embedded in medulla and inner 

cortex; scattered over and bulging from both sides of blades. 

Spermatangia unknown. 

Habitat. On rocks, low intertidal. 

Distribution. Gulf of California: Isla Partida and 

Isla Rasa (Isla Raza), southwestern Islas de La Cintura. 

Type Locality. On rocky shore in lower intertidal; 

Isla Partida (Islas de la Cintura), east of Bahía de Las Ánimas, 

Gulf of California, Mexico. 

Remarks. Mazzaella digitata is a northern Gulf of 

California endemic, apparently with a very restricted range, currently only known from two islands of Islas de la Cintura (Dawson, 1961a, as Rhodoglossum digitatum).

Mazzaella hancockii (E. Y. Dawson) Fredericq

FIGURE 167

Rhodoglossum hancockii E. Y. Dawson, 1944a:304, pl. 71: fig. 1 [type 

specimen]; 1949a:236; 1959a:26; 1961a:259, pl. 61: fig. 2; 1961b:434; 

Dawson et al., 1964:70, pl. 65; D.-H. Kim, 1976:15–16; Norris and 

Bucher, 1976:17, fig. 13; Huerta-Múzquiz, 1978:338; GonzálezGonzález et al., 1996:265. 

Mazzaella hancockii (E. Y. Dawson) Fredericq in Hommersand et al., 

1993:110. 

FIGURE 166. Mazzaella digitata: A. Habit of several fronds (paratypes) (EYD-1045, US Alg. Coll.-12964). B. Transection of paratype (EYD46-983, US Alg. Coll. microscope slide 893).
NUMBER 96 • 337

Gigartina hancockii (E. Y. Dawson) D.-H. Kim, 1976:15–16, 44, 92, figs. 

46–52, 61, 62, 128.

Algae of 1 to several erect, broadly expanding foliose blades, 

up to 20 cm high, 5–8(–12) cm wide; above a short terete stipe, 

1.0–1.5 mm long, 1 mm in diameter, attached below by a discoid 

holdfast. Blades with subdichotomous divisions in upper portions; narrowing upward to an acute tip; margins entire, smooth; 

thin in cross section, only 200–300 μm thick. Medulla of filiform 

filaments. Cortex of 3–5 layers of small cells, 5–7 μm in diameter, with conspicuous intercellular connections; outer layer cells 

usually elongated anticlinally.

Tetrasporangia in sori, 500–700 μm in diameter, scattered 

throughout blades (but absent near blade tips), developed in the 

inner cortex and outer medulla, embedded within thallus. Carpogonial branches 3-celled; supporting cell serves as generative 

auxiliary cell. Cystocarps 500–900 μm in diameter, completely 

embedded internally, scattered throughout blade but absent near 

apices. Spermatangia not seen. 

Habitat. On rocks; low intertidal to 10 m depths. 

Distribution. Gulf of California: Isla Patos (off 

north end of Isla Tiburón) to Isla San Pedro Nolasco; Isla San 

Esteban. Eastern Pacific: Peru.

Type Locality. On rocks, low intertidal; Isla San 

Esteban (Islas de la Cintura), Gulf of California, Mexico. 

Remarks. Mazzaella hancockii may be an endemic 

species in the Gulf of California. The South American record 

from Peru (Dawson et al., 1964; Ramírez and Santelices, 1991) 

should be reexamined to verify its identification. 

Uncertain Record:

Mazzaella affinis (Harvey) Fredericq

Chondrus affinis Harvey, 1841:408.

Mazzaella affinis (Harvey) Fredericq in Hommersand, Guiry, Fredericq, and 

Leister, 1993:110.

Rhodoglossum affine (Harvey) Kylin, 1928:49.

Remarks. Mazzaella affinis has been recorded from 

Roca Rojo, Bahía Kino, by Mendoza-González and Mateo-Cid 

(1986, as “Rhodoglossum affine”). Its presence in the northern 

Gulf needs to be verified.

Uncertain Record:

Mazzaella leptorhynchos (J. Agardh) Leister

Gigartina leptorhynchos J. Agardh, 1885:28.

Mazzaella leptorhynchos (J. Agardh) Leister in Hommersand, Guiry, Fredericq, and Leister, 1993:110.

Remarks. Recorded with uncertainty as to its identification by Mendoza-González and Mateo-Cid (1986, as “Gigartina 

leptorhynchos?”) from Roca Rojo, Bahía Kino. Their northern 

Gulf specimens should be reexamined to identify the species.

FIGURE 167. Mazzaella hancockii: Habit (JN-5563, US Alg. Coll.-160803).
338 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Kallymeniaceae

Kallymeniaceae (J. Agardh) Kylin, 1928:56.

Algae are erect, strongly compressed, ligulate to foliose, and 

usually branched, divided, lacerate, or lobed from a few to several times, but may occasionally be simple. Blades are slippery 

in texture and may be entire, or some species are perforated. 

Thallus construction is multiaxial, with a thin cortex of anticlinal filaments, two to four cells long. Medulla is generally wide, 

pseudoparenchymatous in some members, with large, loosely 

arranged ovoid cells surrounded by slender filaments, whereas 

others have a filamentous medulla of mostly periclinal filaments, 

often intermixed with large refractive stellate cells.

 Life histories involve isomorphic gametophytes and sporophytes. Tetrasporangia are cruciately divided, embedded in the 

cortex, and scattered over blade surfaces. Gametophytes are most 

often dioecious, but one genus can be monoecious (i.e., Euthroa

J. Agardh, 1847). The carpogonial branch is three-celled, and 

species may be monocarpogonial or polycarpogonial. Species are 

procarpic or nonprocarpic. In procarpic species, the carpogonial 

branch and its subsidiary cells develop on a large supporting cell 

that also functions as the auxiliary cell. In nonprocarpic species 

the carpogonial branch is similar to this, but the auxiliary cell 

is the supporting cell of a distant branch system. Auxiliary cell 

branches also bear several one- to two-celled chains of ovoid 

to lobed subsidiary cells that may function as nutritive cells for 

the developing carposporophyte. After fertilization, the carpogonial fusion cell produces connecting filaments for transfer of the 

diploid nucleus to auxiliary cells in nonprocarpic genera. Cystocarps are globose and may be large and are often surrounded by 

a thin filamentous involucre. Spermatangia develop in patches, 

cut off from outer cortical cells. 

Remarks. Two genera of the Kallymeniaceae are 

found in the northern Gulf of California.

KEY TO THE GENERA OF KALLYMENIACEAE AND CROSSOCARPACEAE 

IN THE NORTHERN GULF OF CALIFORNIA

1a. Blade medulla of large pseudoparenchymatous-like cells surrounded by branching, slender filaments of short, pigmented 

cells; cortex mostly of 2–3 cell layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pugetia

1b. Blade medulla filamentous; of interwoven, mostly periclinal filaments, intermixed with some, usually conspicuous, refractive cells; cortex mostly of 3–4 cell layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Medulla with elongate, branched, spiniferous, refractive cells (not stellate) . . . . . . . . . . . . . . . . . . . . . . Kallymeniopsis

2b. Medulla with stellate refractive cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kallymenia

Kallymenia J. Agardh

Kallymenia J. Agardh, 1842:98

Algae are simple to lobed foliose blades, with a firm but 

slippery texture, sometimes spinose. Blades may be intact or 

perforated by holes of various shapes and sizes. The medulla is 

composed of loosely interwoven filaments, most of which are 

periclinally directed. Interspersed among these medullary filaments are large stellate (arachnoid) or giant cells with long extensions. These stellate cells contain highly refractive contents 

and stain deeply. The cortex is composed of (2–)3–4 small, pigmented cells, in more or less anticlinal rows, decreasing in size to 

the thallus surface. 

Tetrasporophyte and gametophytes are isomorphic. Tetrasporangia are cruciately divided and scattered in the cortex over 

the blade. Carpogonial branches are three-celled, either monocarpogonial or polycarpogonial, and borne on a supporting cell 

bearing subsidiary cells. Auxiliary cells are ovoid, surrounded by 

three to eight subspherical to ovoid subsidiary cells, and borne 

on separate filaments distant from the carpogonial branches. 

After presumed fertilization, the carpogonial fusion cell develops and initiates connecting filaments that grow to auxiliary 

cells. When the connecting filaments contact auxiliary cells, the 

diploid nucleus is transferred, and gonimoblast tissue develops, 

and carposporangia are produced. Cystocarps are globose, often 

large, and surrounded by loose filaments. Spermatangia are in 

irregular superficial patches. 

Remarks. Currently there are four species known in 

the Gulf of California. One of which, Kallymenia norrisii Hollenberg et I. A. Abbott (1965), was recently reported in the southern 

Gulf from off Isla San José and Isla Santo Espíritu (HernándezKantún et al., 2010). 

There are three species of Kallymenia, all endemic, known 

in the northern Gulf of California. 

KEY TO THE SPECIES OF KALLYMENIA (KALLYMENIACEAE) AND KALLYMENIOPSIS

(CROSSOCARPACEAE) IN THE NORTHERN GULF OF CALIFORNIA

1a. Blades of various shapes, mostly more or less round or oval to irregular; distinctively and thoroughly perforated with 

numerous holes 2–4(–10 cm) in diameter; not lacerated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kallymenia pertusa

1b. Blades usually entire, cuneate to broadly lobed, or lacerated; without perforations (or if present, only with very few 

holes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Blades lacerated to within 3 cm of holdfast; 200–270 μm thick; cracking upon drying . . . . . . . . . . . Kallymenia bleckii

2b. Blade segments broadly lanceolate to lobed or deeply lacerated; not cracking upon drying . . . . . . . . . . . . . . . . . . . . . 3
NUMBER 96 • 339

3a. Blade wider than tall; segments narrow, deeply, palmately lacerate down to within 1 cm of holdfast; 250–300 μm thick; 

medulla with stellate refractive cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kallymenia baldwinii

3b. Blades broadly lanceolate or broad with cuneate divisions (not lacerated); generally thinner, 100–250 μm thick; medulla 

with elongate, branched, spiniferous refractive cells (not stellate) . . . . . . . . . . . . . . . . . . . Kallymeniopsis oblongifructa

Kallymenia baldwinii E. Y. Dawson

FIGURE 168A

Kallymenia baldwinii E. Y. Dawson, 1966b:62, fig. 3A; Abbott, 1968:196; 

González-González et al., 1996:230. 

Blades erect, dull rose in color; solitary; broader than tall, 

up to 14 cm tall and 24 cm wide; blade deeply, palmately lacerated (to within 1 cm of holdfast) into narrow segments, mostly 

3–20 mm wide; without a stipe, attached by small discoid holdfast. Lowermost portion of blade, with faint, palmate, vein-like 

thickenings, about 1 cm long, extending into lacerate segments. 

Blades 250–300 μm thick. Medulla of slender filaments, outwardly joining large stellate cells, 40–50 μm in diameter. Inner 

cortex of rotund cells, about 20 μm in diameter; outer cortex 

of branched anticlinal filaments of 2–3 cells; outermost cortical 

cells about 5 μm in diameter.

Tetrasporangia not known. Cystocarps about 500 μm in diameter, bulging on either side of blade surface; scattered in upper 

portions of blade, 6–7 cm from base. Spermatangia not known.

Habitat. On rocks; subtidal, down to 20 m depths.

Distribution. Gulf of California: Islas Santa Inez 

(Bahía Concepción). 

Type Locality. Off Islas Santa Inez (Bahía Concepción), Baja California Sur, Gulf of California, Mexico. 

Remarks. Although currently known only from the 

type, more subtidal collecting should find Kallymenia baldwinii

elsewhere in the Gulf.

Kallymenia bleckii E. Y. Dawson

FIGURE 168B

Kallymenia bleckii E. Y. Dawson, 1966b:59, fig. 3B; Abbott, 1968:196; 

González-González et al., 1996:230. 

Blades erect, brownish rose to dark rose (becoming brittle 

and cracking on drying); apparently solitary; up to 24 (or more) 

cm tall and 28 (or more) cm wide; blade irregularly lacerated 

(to within 3 cm of base) into broad lobed segments; with only a 

few perforations, 2–5 mm in diameter; without a stipe, attached 

by small holdfast. Lowermost portion of blade with faint, divided “veins” in 3–4 cm radius around base (not seen beyond 

this area). Blades 200–270 μm thick in outer portions; inner medulla of slender filaments, outwardly joining 1–2 irregular layers 

of stellate cells, 15–25(–40) μm in diameter; cortex of anticlinal 

rows of 2–3 small pigmented cells; outer cortical cells, 4–8 μm 

in diameter. 

Tetrasporangia not known. Cystocarps about 600 μm in diameter, conspicuously bulging on either side of blade; scattered 

in upper half of blade. Spermatangia not known.

Habitat. On rocks; subtidal, down to 15 m depths.

Distribution. Gulf of California: Isla San Pedro 

Nolasco (off Guaymas); Punta Púlpito (east of the southern end 

of Bahía Concepción on coast of Baja California Sur).

Type Locality. Punta Púlpito (El Púlpito), Baja 

California Sur, Gulf of California, Mexico. 

Kallymenia pertusa Setchell et N. L. Gardner

FIGURE 169

Kallymenia pertusa Setchell et N. L. Gardner, 1924:746, pl. 49: fig. b; Dawson, 1944a:287; 1954c:303; 1961b:425 [with generic query]; Norris and Norris, 1973:71, figs. 1–5; Norris and Bucher, 1976:11, fig. 

9; González-González et al., 1996:231; Riosmena-Rodriguez et al., 

1998:28; Pacheco-Ruíz et al., 2008:208; Hernández-Kantún et al., 

2010:2. 

Blades of various shapes, rose red, mostly round or oval to irregular in outline, up to 50 cm long and 30 cm wide, 300–370 μm 

thick, with numerous conspicuous perforations; margins slightly 

undulate; attached at 1 or more points by small, swollen holdfasts 

on blade margins. Perforations initially small and round, becoming 

larger and irregular in shape as they merge together, (3.0–)5.0–40(–

100) mm in diameter. Medulla of loosely interwoven filaments, and 

abundant large branched, highly refractive stellate cells. Cortex of 

anticlinal rows of 2–4 small, elongated pigmented cells.

Tetrasporangia cruciately divided, 24–30 μm long and 16–22 

μm in diameter; embedded in the cortex and scattered over thallus surface. Carpogonial branches polycarpogonial, with up to 7 

carpogonial branches on 1 supporting cell. Auxiliary cell system 

with several 1- to 2-celled subsidiary branches. Cystocarps 0.5–

1.0 mm in diameter, surrounded by a thin involucre of narrow 

filaments, lacking an ostiole, and immersed and scattered over 

blade. Spermatangia 2.5–5.0 μm, with 1 or 2 developed from 

each outer cortical cell, forming superficial patches. 

Habitat. On rocks, large shells, or rhodoliths or epiphytic or entangled with other algae; subtidal, from 6 to 27 m 

depths. 

Distribution. Gulf of California: Isla Mejía (northwest side of Puerto Refugio, Isla Ángel de la Guarda); Canal de 

Ballenas (between west coast of Isla Ángel de la Guarda and east 

coast of Baja California); Punta La Gringa (Bahía de Los Ángeles); Isla San Esteban; Isla San Pedro Mártir; Isla San José. 

Type Locality. Isla San Pedro Mártir (about 35 km 

south of Punto de Monumento on southern end of Isla Tiburón), 

southeastern Islas de la Cintura, Gulf of California, Mexico. 

Remarks. On the basis of the finding of cystocarpic 

material, Norris and Norris (1973) clarified the taxonomic position of Kallymenia pertusa. Subtidal collections from the R/V 

Dolphin cruise have shown K. pertusa not to be as rare as previously thought (Norris and Bucher, 1976). Though occasional in 

distribution, K. pertusa can be abundant where found and was 

particularly common at 20–27 m depths, off Isla Mejía and off 

Roca Blanca, Puerto Refugio, Isla Ángel de la Guarda. Diving 

observations suggest that K. pertusa develops subtidally at these 

depths, attached to rocks and large pieces of shells. It has also 
340 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 168. Two Gulf of California endemic species of Kallymenia. A. Kallymenia baldwinii: Holotype specimen (EYD-25819, US Alg. Coll.-

40928). B. Kallymenia bleckii: Holotype specimen (EYD-25919, US Alg. Coll.-40927).
NUMBER 96 • 341

FIGURE 169. Kallymenia pertusa: Habit, showing the characteristic perforated blade (JN-5667, US Alg. Coll.-217346).
342 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

been reported in subtidal rhodolith beds (Hernández-Kantún et 

al., 2010). Large blades of K. pertusa, such as those found at Isla 

San Esteban and Punta La Gringa (Bahía de Los Ángeles), can 

become unattached or torn, perhaps because of age or size or possibly from grazing or prevailing currents, with blade fragments 

then drifting and becoming entangled with other algae at shallower depths (6–15 m), where they appear to continue growing. 

Pugetia Kylin 

Pugetia Kylin, 1925:30; Norris, 1957:263, 266, figs. 3A–G, 4A–E, 5A–D 

[details of generitype P. fragilissima Kylin]; Clarkston and Saunders, 

2012:43.

Algae are erect foliose blades, lack a midrib, and may be circular to wider than tall, palmately or irregular divided, or lobed. 

Most are entire, but at least one has holes in the surface. Blades 

either lack or arise above a short stipe and are attached below by 

one or more small discoid holdfasts. Multiaxial in structure, the 

medulla is pseudoparenchymatous, composed of large, round 

to oval, unpigmented cells that are interspersed with branching, 

slender filaments composed of small pigmented cells. The cortex is thin, consisting of two to three cells, with cells becoming 

smaller toward the surface.

Tetrasporophyte and gametophytes are isomorphic. Tetrasporangia are cruciately divided, embedded in the cortex, and 

scattered over the blade. Carpogonial branches are composed of 

three, round, oval or slightly lobed cells on a supporting cell, and 

usually with one or more subsidiary cells. Thalli are nonprocarpic, and the auxiliary cell systems are separate and distant from 

the carpogonial branch. After fertilization the dipoloid nucleus 

of the carpogonium is transferred to the supporting cell, which 

enlarges and produces lobed protuberances that issue connecting 

filaments to separate auxiliary cells, which in turn generate the 

gonimoblast filaments with terminal carposporangia. Cystocarps 

are relatively small, develop within the medulla and cortex, and 

when mature, they bulge on one side of the blade. Spermatangia 

are superficial on the outer cortical cells.

Remarks. Molecular, morphological, and anatomical analyses by Clarkston and Saunders (2012) revealed that one 

new species of Pugetia grouped with the generic type (P. fragilissima Kylin, 1925) whereas other species previously considered 

to be “Pugetia” were in two divergent clusters of the Kallymeniaceae. Some belonged in a new genus, Salishia Clarkston et G. 

W. Saunders, and one was a new species of Beringia Perestenko 

(1975) that grouped with Erythrophyllum delesserioides and 

Kallymeniopsis oblongifructa.

One species of Pugetia is known in the northern Gulf of 

California.

Pugetia mexicana E. Y. Dawson

FIGURE 170

Pugetia mexicana E. Y. Dawson, 1966b:62, fig. 6G,H; Norris, 1973:10; 

Norris and Bucher, 1976:13, fig. 10; Ramírez, 1982:12, figs. 1, 

18; Ramírez and Santelices, 1991:244; González-González et 

al., 1996:264; Pacheco-Ruíz and Zertuche-González, 2002:467; 

Pacheco-Ruíz et al., 2008:208.

Algae membranous blades, up to 20 cm tall and to 15–35 

cm wide, soft and slippery in texture, rose red in color; blades 

(170–)250–300 μm thick, subdichotomously divided 2–5 times; 

upper portions often more or less palmate or sometimes irregularly to deeply divided; with entire to irregular or lobed margins 

and rounded terminal portions (3–5 mm wide); blades sometimes overlapping with portions often attached to each other; 

lowermost portion occasionally partially prostrate, attached by 

1 or more small discoid holdfasts. Medulla pseudoparenchymatous; of 2(–3) layers of large parenchyma-like cells, 60–100 μm 

or more in diameter, and slender filaments of small, mostly elongated, pigmented cells interspersed among the large medullary 

cells. Cortex of 2–3 cell layers; of very small rounded cells; in 

surface view, about 2–3 μm in diameter; in transection oval to 

slightly elongate, 3–5 μm in diameter.

Tetrasporangia cruciately divided, 24–27(–30) μm long, 

12–15 μm in diameter; embedded in the cortex, scattered in 

upper portions of blade. Cystocarps to 700 μm in diameter, without ostioles; scattered, embedded, and bulging on both surfaces. 

Carposporangia (10–)12–15 μm in diameter. Spermatangia superficial, derived from outer cortical cells on upper portion of 

thallus; spermatia about 2 μm in diameter. 

Habitat. On rocks, mollusk shell fragments, and hydroids; sudtidal, 4.5–22 m depths (also dredged from 19–30 m 

depths; Dawson, 1966b). 

Distribution. Gulf of California: Isla Mejía, Roca 

Blanca and Puerto Refugio, Isla Ángela de la Guarda, Isla Estanque, Isla San Esteban, and Isla San Lorenzo (Islas de la Cintura); Punta La Gringa, Bahía de Los Ángeles, to Bahía San 

Francisquito (Baja California). Eastern Pacific: northern Chile.

Type Locality. Off Isla San Lorenzo (Isla San Lorenzo Sur), largest of the Islas de San Lorenzo off the east coast 

of Baja California, southwestern Islas de la Cintura, Gulf of California, Mexico. 

Remarks. There are two morphs of Pugetia mexicana in the northern Gulf. The subtidal specimens of Norris and 

Bucher (1976: fig. 10) tentatively referred to P. mexicana were 

much larger and subdichotomously to palmately divided, differing from the type specimen, a smaller irregularly shaped blade 

with irregular lobed margins and occasional long extensions 

(Dawson, 1966b: fig. 6G, H). However, both morphs have the 

same female reproductive systems (R. E. Norris, Friday Harbor 

Marine Laboratories, personal communication). Tetrasporangia (JN-5604, US Alg. Coll. microscope slide 4358) and spermatangia (JN-5427, US Alg. Coll. microscope slide 4242) are 

now reported for the larger, subdichotomously divided morph of 

P. mexicana. The type specimen described by Dawson (1966b) 

could possibly have been a fragment of a larger thallus, as similar morphologies were observed on upper parts of a Punta La 

Gringa specimen referred to P. mexicana (JN-5427, US Alg. 

Coll.-160776). The morphological differences and phylogenetic 

relationships of these morphs and the type need to be further 
NUMBER 96 • 343

FIGURE 170. Pugetia mexicana: A. Habit, a large blade (JN-5668, US Alg. Coll.-217349). 

B. Small blade with scattered cystocarps (JN-5362, US Alg. Coll.-160774). 
344 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

tested and molecular analyses performed when more material of 

each is collected. 

Pugetia mexicana, a northern Gulf species, has also been 

reported from Antofagasta, Chile (Ramírez, 1982; Ramírez and 

Santelices, 1981). 

Uncertain Record:

Callophyllis violacea J. Agardh

Callophyllis violacea J. Agardh, 1885:34; Mendoza-González and MateoCid, 1986:423; Gonzáles-González et al., 1996:211(in part).

Remarks. Callophyllis violacea was mistakenly reported from the northern Gulf (Norris, 1973). The specimen (JN369) was a gift, but the locality was apparently mislabeled and it 

is not from Bahía Bocochibampo. It was subsequently recorded 

from Guaymas (Mendoza-González and Mateo-Cid, 1986), but 

since then has not been reported in the northern Gulf. These specimens need to be reexamined before its presence can be verified.

Crossocarpaceae

Crossocarpaceae Perestenko, 1975:1679.

Algae have entire margins and mostly simple to divided 

blades, with a few having stalked proliferations. Medulla is composed of large cells, relatively short-celled filaments, and slender 

filaments, with elongate, branched, and spinulose refractive cells. 

Cortex is relatively thin, with cortical cells becoming progressively smaller toward the thallus surface.

Tetrasporophytes and gametophytes, where known, are 

isomorphic. Tetrasporangia are irregularly cruciately divided; 

scattered in the cortex, attached laterally to outer cortical 

cells. Female reproductive structures develop within the blades 

or in marginal or surface proliferations (i.e., Erythrophyllum

J. Agardh, 1872). Carpogonial branches are three-celled and 

borne on a clavate to lobed supporting cell along with up to four 

clavate to lobed subsidiary cells. Auxiliary cells, with up to four 

subglobose subsidiary cells, develop on a different branch system. After fertilization, the carpogonial fusion cell develops from 

the carpogonium, supporting cell, and subsidiary cells, initiating 

branched, connecting filaments that contact both auxiliary cells 

and specialized vegetative accessory filaments. Gonimoblast filaments appear to develop from the accessory filaments. Carposporangia are produced in clusters at the apices of gonimoblast 

filaments, and an embedded, large, diffuse cystocarp forms without an ostiole. Spermatangia are unknown.

Remarks. The status of the family Crossocarpaceae 

has been under contention (Lobban and Wynne, 1981; Selivanova, 2002). Hansen and Lindstrom (1984; Scagel et al., 1989) 

treat it as a subgroup of the Kallymeniaceae, whereas others 

have accepted the family (Perestenko, 1986, 1996; Zinova and 

Gussarova, 1977; Schneider and Wynne, 2007; Guiry and Guiry, 

2008–2010). The phycocolloid composition of some species of 

Crossocarpaceae were heterogeneous, indicating the need for 

their taxonomic reexamination (Chopin et al., 1999). 

One genus is reported in the northern Gulf of California.

Kallymeniopsis Perestenko

Kallymeniopsis Perestenko, 1977:398; Perestenko, 1996:103, pl. 10: figs.13–

21, pl. 31: fig. 6.

Kallymeniopsis Perestenko, 1975:1679, nom. invalid.

Foliose algae that are obovate, orbiculate, reniform, or circinate in shape, growing from a short stipe and a fleshy a discoid 

holdfast. Blades may be entire, lobed, or lacerated into broadly 

lanceolate to wedge-shaped segments; with smooth margins and 

a blade surface that may be smooth, undulate, or sometimes verrucose. Internal structure is composed of a filamentous medulla, 

with elongate, branched spiniferous refractive cells. The cortex is of 

mostly isodiametric cells that become smaller toward the surface. 

Tetrasporophytes and gametophytes, where known, are isomorphic. Tetrasporangia are cruciately divided and scattered in 

the cortex over the blade. Carpogonial branch is 3-celled; each 

carpogonial branch is borne on the supporting cell together with 

up to 4 subsidiary cells. After presumed fertilization, the fusion 

cell develops from the carpogonium, supporting cell, and subsidiary cells. Auxiliary cells are borne on separate branch systems. 

Cystocarps are immersed to protruding, with sterile filaments interspersed among groups of carposporangia. Spermatangia occur 

in large soral areas scattered over the surface of the blade. (G. I. 

Hansen, Oregon State University, personal communication).

Remarks. The generic status of Kallymeniopsis

Perestenko may require further elucidation. Although Hansen 

(1997) has accepted the genus, Lindstrom (in Guiry and Guiry, 

2009) suggested the genus may be congeneric with Kallymenia. 

Molecular analysis by Clarkston and Saunders (2010: fig. 2) revealed British Columbia Kallymeniopsis oblongifructa to be in a 

clade with another member of the Kallymeniaceae, Erythrophyllum delesserioides J. Agardh (1872; generitype; type locality: 

Vancouver Island), and also with Hommersandia palmatifolia (Tokida) Perestenko ex O. N. Selivanova et G. G. Zhigadlova (1997; basionym: Pugetia palmatifolia Tokida, 1948:37; 

type locality: Higasi-soya, Saghalien, Japan). This clade was 

distinct from a clade with the generitype of Kallymenia, i.e., 

K. reniformis (Turner) J. Agardh (1842; type locality: Isle of 

Wight, SE England, UK) and supports the generic separation of 

Kallymeniopsis. 

Perestenko (1977) treated Kallymeniopsis as a member of 

the family Crossocarpaceae. Although this placement of the genus 

has been accepted by some (Perestenko, 1986, 1996; Zinova and 

Gussarova, 1977; Schneider and Wynne, 2007), others contend it 

should be treated in the Kallymeniaceae (e.g., Hansen and Lindstrom, 1984; Scagel et al., 1989; Clarkston and Saunders, 2012). 

In Clarkston and Saunders (2010) the Kallymeniopsis clade is 

basal in the Kallymeniaceae tree, suggesting it could be treated 

either way. Herein, it is tentatively treated in the Crossocarpaceae 

until the generitype, Kallymeniopsis lacera (Postels et Ruprecht) 

Perestenko (1977; basionym: Iridaea lacera Postels et Ruprecht, 

1840), can be further morphologically and molecularly tested. 

Kallymeniopsis is primarily a subboreal to cold-temperate 

genus known in the North Pacific from the Kuril Islands 
NUMBER 96 • 345

(“Kurile”) and Okhotsk Sea (Russia) to Alaska (Perestenko, 

1996). One species, Kallymeniopsis oblongifructa, recorded 

from Alaska to northern California in the northeastern Pacific 

(Scagel et al., 1989; Hansen, 1997), was recently reported in the 

northern Gulf of California (Hernández-Kantún et al., 2010, as 

Kallymenia oblongifructa). 

Kallymeniopsis oblongifructa (Setchell) G. I. Hansen

Iridaea oblongifructa Setchell, 1901:123; Setchell and Gardner, 1903:300.

Kallymeniopsis oblongifructa (Setchell) G. I. Hansen, 1997:194; Clarkston 

and Saunders, 2010:129, tbl. 1, figs. 1, 2; Clarkston and Saunders, 

2012: figs. 1–4.

Kallymenia oblongifructa (Setchell) Setchell, 1912:234 [as “Callymenia oblongifructa”]; Abbott, 1968:197; Abbott and Hollenberg, 1976:454, 

fig. 402; Lindstrom, 1977:177; Scagel et al., 1989:203; HernándezKantún et al., 2010:2, fig. 3A–D.

Algae foliose; single or in clusters of several erect blades, 

10–15(–30) cm tall; simple, obovate or broadly lanceolate and 

often lobed, with smooth margins; blades 100–250 μm thick; 

short stipe above a fleshy discoid holdfast. Medulla of periclinal 

filaments, 3–4 μm in diameter, and some elongate, spiniferous 

refractive cells running parallel to the periclinal medullary filaments. Cortex of 3–4 layers of cells, decreasing in size outwardly; 

inner cortical cells up to 45 μm in diameter, with projections 

or stellate-like extensions (as the thallus expands, subcortical 

cells become stretched between pit connections to form these 

stellate-like cells; G. I. Hansen, Oregon State University, personal 

communication); outer cortical cells mostly 4 μm in diameter 

(description after Hernández-Kantún et al., 2010). 

Tetrasporangial, cystocarpic, and spermatangial thalli not 

known in Gulf of California.

Habitat. Epiphytic on rhodoliths (crustose coralline 

nodules); rhodolith beds in subtidal channels with strong currents; 13–20 m depths.

Distribution. Gulf of California: Isla San Pedro Nolasco. Eastern Pacific: Bering Sea and Aleutian Islands, Alaska to 

Mendocino County, northern California. Western Pacific: Russia.

Type Locality. Cast ashore, on stipes of kelp; 

Whidbey Island (“Whidby”), Island County, Puget Sound, Washington, USA.

Remarks. Kallymeniopsis oblongifructa was recently reported in the warmer subtidal waters of the northern 

Gulf of California by Hernández-Kantún et al. (2010, as Kallymenia oblongifructa). Their specimens were described as “cuneately divided,” a character of Kallymeniopsis lacera (Postels 

et Ruprecht) Perestenko (1977; G. I. Hansen, Oregon State University, personal communication, 2010). This is a remarkable 

find since K. oblongifructa was previously known only in the 

colder subtidal waters of the northeast Pacific (Alaska to northern California). The northern Gulf Kallymeniopsis oblongifructa needs to be further studied and compared molecularly 

with type locality materials of K. oblongifructa and K. lacera

and with other Gulf members of the Kallymeniaceae to elucidate 

their relationships.

Phyllophoraceae*

Phyllophoraceae Rabenhorst, 1863:281.

The Phyllophoraceae is a small family composed of erect, 

cylindrical to compressed thalli, which are mostly dichotomously 

branched. Most members are rather firm in texture. They are 

multiaxial, with growth occurring from marginal or apical meristems. Internal structure is usually pseudoparenchymatous, with 

a medulla that is composed of large compacted isodiametric cells 

or slender parallel longitudinal filaments and a cortex of similar 

but much smaller cells. 

This family exhibits a wide diversity of reproductive adaptations and life histories, which can be isomorphic, heteromorphic, 

apomictic, or tetrasporoblastic. Members can be isomorphic, 

with erect tetrasporophytes and gametophytes; or distinctly 

heteromorphic, with erect gametophytes and crustose tetrasporophytes; or erect gametophytes (without separate tetrasporophytes) that produce tetrasporangia in nemathecia. There is also 

one genus that is parasitic. In all cases the tetrasporangia are 

cruciately divided and either develop in bead-like chains on an 

isomorphic tetrasporophyte or within nemathecia developed on 

a monoecious gametophyte or in a crustose thallus of those with 

heteromorphic tetrasporophytes and gametophytes. The female 

reproductive apparatus is a procarp consisting typically of a 

three-celled filament with a supporting cell also bearing a sterile 

filament. This supporting cell becomes the auxiliary cell. Cystocarps are embedded within the thallus, often filling the entire 

cross section of the branch. The gonimoblast filaments develop 

small carposporangia that are formed in dense, crowded compartments among sterile tissue. Spermatangia, where known, are 

developed in superficial sori but have not been convincingly described for many of the species. 

There are three genera of the Phyllophoraceae represented 

in the northern Gulf of California.

KEY TO THE GENERA OF PHYLLOPHORACEAE IN THE GULF OF CALIFORNIA

1a. Thalli of distinctly flat, narrow blades; isomorphic; tetraspores cruciately divided, in chains within nemathecia . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Petroglossum

1b. Thalli terete or compressed to flattened branches; heteromorphic or tetrasporoblastic; tetrasporangia cruciately divided, 

in chains in crustose thalli, or irregularly divided in large nemathecia on branch surfaces . . . . . . . . . . . . . . . . . . . . . . 2

* Contributed by James N. Norris and Suzanne Fredericq. S. Fredericq: 

Department of Biology, University of Louisiana at Lafayette, Lafayette, 

Louisiana 70504, USA.
346 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

2a. Erect gametophytes of narrow terete to compressed branches, 0.5–2.5 mm wide; life history heteromorphic, tetrasporophytes a separate crustose phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ahnfeltiopsis

2b. Erect gametophytes of terete, compressed, or flattened branches; life history tetrasporoblastic, monoecious gametophyte 

with gonimoblasts (“tetrasporoblasts”) developed from auxiliary cells within the medulla that grow outward to produce 

tetrasporangia within conspicuous, large, external nemathecia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gymnogongrus

Ahnfeltiopsis P. C. Silva et DeCew

Ahnfeltiopsis P. C. Silva et DeCew, 1992:576.

Gametophytes are upright, slightly to very rigid, of narrow, 

terete to flattened axes that are infrequently to repeatedly dichotomously, subdichotomously, or irregularly branched. They 

arise above discoid holdfasts, which are often covered with terete, rhizome-like, lowermost, prostrate branches. The medulla 

is pseudoparenchymatous, composed of slender, parallel longitudinal filaments. The cortex is composed of small cells in anticlinal rows. 

Life histories are heteromorphic, with erect gametophytes 

and a fleshy crustose tetrasporophyte (Masuda et al., 1979; Masuda, 1981; DeCew and West, 1981; Fredericq and Ramírez, 

1996; Masuda and Kogame, 1998; Fredericq and Lopez-Bautista, 

2002; Fredericq et al., 2003). A direct life history in which the 

female gametophytes apomictically produce carposporophytes is 

also known for some species (DeCew and West, 1981; Masuda 

and Norris, 1994). Tetrasporophytic crusts produce cruciately 

divided tetrasporangia in intercalary chains. Erect female gametophytes develop a three-celled carpogonial branch on a supporting cell that is functionally an auxiliary cell. The first cell of the 

carpogonial branch bears a sterile cell. Cystocarps are produced 

internally, as they develop within the medulla the cortex thickens 

and protrudes, and pores (carpostomes) of short periclinal filaments are formed from the anticlinal cortical cells. Carpospores 

are released through the carpostomes. Spermatangia are elongate, four to five times longer than in diameter, and develop in 

pairs in superficial sori. 

There are four species known in the northern Gulf of 

California.

KEY TO THE SPECIES OF AHNFELTIOPSIS IN THE NORTHERN GULF OF CALIFORNIA

1a. Branched infrequently, subdichotomously, 1–3 orders; branches simple, terete to slightly compressed below, above flattened, strap shaped, up to 2.5 mm wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. serenei

1b. Branched repeatedly dichotomously to subdichotomously, up to 4–8 (or more) orders . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Branches compressed to flattened, less than 1 mm wide; margins without lateral proliferations; apices forked to digitate

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A. hancockii

2b. Branches compressed to flat, wider than 1 mm, up to 2–3 mm wide; apices simple to divaricate . . . . . . . . . . . . . . . . . 3

3a. Branches flattened throughout (except the very short stipe); mostly 2.0–3.0 mm wide; with few to many lateral proliferations, up to 1 cm long; branch apices divaricate, much narrowed in width, with pointed tips . . . . . . . . . . A. divaricata

3b. Branches initially compressed, becoming markedly flattened upward narrower; 1.0–1.5 mm wide . . . . . . A. leptophylla

Ahnfeltiopsis divaricata (Holmes) Masuda

Gymnogongrus divaricatus Holmes, 1896:255, pl. 8: fig. 3a,b; Okamura, 1934a:16, pl. 310: fig. 105; Dawson, 1944a:301, pl. 71: 

fig. 2 [two specimens on right]; Masuda, 1987:55, figs. 10A–C 

[holotype], 11A–H, 12A–G; González-González et al., 1996:

220.

Ahnfeltiopsis divaricata (Holmes) Masuda, 1993:2; Masuda et al., 1994:168, 

figs. 6, 20, 21, 32; Yoshida, 1998:776; Abbott, 1999:160, fig. 39F.

Algae erect, up to 3(–5) cm tall, repeatedly dichotomously 

branched at wide angles, up to 5 or more orders; branches mostly 

2.0–3.0 mm wide; initial axis more or less terete above basal attachment disc, abruptly becoming compressed upward; branches 

without or with few to many lateral proliferations; branch apices narrowed to about 1.0 mm wide; uppermost tips divaricate, 

pointed, about 5 mm wide. Medulla of large colorless cells; cortex of small, pigmented cells in anticlinal rows.

Tetrasporophytes not known in Gulf. Reproductive structures 

develop on margins and surfaces of upper branches and lateral proliferations. Cystocarps prominent, 550–750 μm tall, 500–1000 μm 

wide; with several carpostomes. Spermatangia in sori near branch 

apices; 1–2 develop from spermatangial parent cell; spermatia elongated, 10–12 μm tall, 2–3 μm wide (after Masuda, 1987). 

Habitat. On rocks; low intertidal. 

Distribution. Gulf of California: Puerto Lobos; 

Isla Turner (off SE end of Isla Tiburón). Central Pacific: Hawaiian Islands. Western Pacific: Japan; Philippines. 

Type Locality. Shimoda, southern Izu Peninsula, 

Shizuoka Prefecture, central Japan (Masuda, 1987:54).

Remarks. Specimens of the northern Gulf are tentatively referred to Ahnfeltiopsis divaricata. These may sometimes 

be confused with some smaller forms of Gymnogongrus johnstonii. Although Dawson (1961a, as G. johnstonii) thought the 

Gulf material of these represented only one species, there appears to be two species among his collections. 

The most obvious difference between them is a generic 

character, which can be seen in life history studies: Ahnfeltiopsis has a heteromorphic life history (erect gametophytes 

and crustose tetrasporophytes), whereas Gymnogongrus has a 
NUMBER 96 • 347

tetrasporoblastic type of life history (tetrasporangia produced 

in wart-like nemathecia). Thus, reproductive characters of 

some similar-looking specimens of Gulf Ahnfeltiopsis divaricata will have cystocarps, and those of smaller Gymnogongrus 

johnstonii will have nemathecia with tetraspores. Gulf material 

referred to A. divaricata should be molecularly compared with 

those from Japan as well as with the Gulf G. johnstonii to test 

its taxonomic status. 

Specimens of A. divaricata from Peru (Acleto O., 1973:57, 

as “G. divaricatus,” fig. 197) are probably a different species. 

On the basis of rbcL sequence analysis, Ahnfeltiopsis divaricata

from Hawaii was found to be a distinct species from G. johnstonii (Fredericq and Lopez-Bautista, 2002).

Ahnfeltiopsis hancockii (E. Y. Dawson) J. N. Norris et 

Fredericq, comb. nov.

FIGURE 171

Gymnogongrus hancockii E. Y. Dawson, 1944a:300, pl. 71: fig. 2 [upper 

left]; 1950b:337 [in part], fig. 1 [left large specimen only]; GonzálezGonzález et al., 1996:221; Fernández-García et al., 2011:62.

Gymnogongrus johnstonii sensu Dawson, 1961a:250 [in part, only small 

“depauperate forms”], pl. 43 [lower left insert only] [non Gymnogongrus johnstonii (Setchell et N. L. Gardner) E. Y. Dawson, 1954c:294; 

basionym: Callophyllis johnstonii Setchell et N. L. Gardner, 1924:746].

Algae usually in clumps, 2.0–4.5 cm tall, of compressed to 

flattened, narrow branches, 1–3 mm wide; branching subdichotomously, often widely divaricate, at 2–5 mm intervals; branches 

about 300 μm in thickness, with smooth surfaces, margins usually without lateral proliferations or, if present, sparse and short, 

usually less than 2 mm in length, and with slightly pointed apices; branch tips divided 2 times (forked) or 3–4 times (digitate).

Tetrasporangia more or less cruciately divided; within large, 

irregularly shaped, globose nemathecia, up to 1.0 mm in diameter, mostly on margins, sometimes on surfaces in upper portions 

of the branches. Cystocarps about 450 μm in diameter; partly 

embedded within frond surface and protruding about 200–300 

μm above surface; with several carpostomes. 

Habitat. On rocks; mid to low intertidal.

Distribution. Gulf of California: San Felipe to 

Santa Rosalía; Bahía San Francisquito; Mazatlán. Eastern Pacific: Costa Rica.

Type Locality. “Point approximately 3 miles [~4.8 

km] north of Kino” (Dawson, 1944a); probably in the vicinity 

of Kino Nuevo (north of Kino Viejo), Bahía Kino, Sonora, Gulf 

of California. 

Remarks. Although the combination Ahnfeltiopsis 

hancockii is proposed, it is with some reservation that this species is reinstated. The Gulf A. hancockii seems to be close to 

A. divaricata, differing mostly in being sparsely branched and 

usually without lateral proliferations. Specimens of A. hancockii

need to be critically compared with Gulf material referred to 

A. divaricata and to type material from Japan (cf. Masuda, 1987, 

1993). Although Dawson (1961a, as Gymnogongrus hancockii) 

without comment considered Ahnfeltiopsis hancockii to be a 

FIGURE 171. Ahnfeltiopsis hancockii: A. Habit (EYD-405, US Alg. Coll.-208111). B. Tetrasporangial nemathecia, mostly borne on margins 

(JN-3228, US Alg. Coll.-159896).
348 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

“depauperate form” conspecific with G. johnstonii, herein these 

two are separated on their habit and reproductive morphology 

(cystocarps in A. hancockii and nemathecia with tetrasporangia 

in G. johnstonii). Other Pacific Mexico records of “depauperate forms” of G. hancockii sensu Dawson (1961a) from Jalisco, 

Guerrero, Oaxaca, and Isla Socorro (Islas Revillagigedo) may 

also be A. hancockii.

Ahnfeltiopsis leptophylla (J. Agardh) P. C. Silva et DeCew

Gymnogongrus leptophyllus J. Agardh, 1876:211; Kylin, 1941:26; Smith, 

1944:273, pl. 65: fig. 1; Dawson, 1945c:61; Dawson et al., 1960a:64, 

pl. 32: fig. 1; Dawson, 1961a:251, pl. 40: fig. 3; 1961b:431; Abbott and 

Hollenberg, 1976:506, fig. 453; DeCew and West, 1977b:118; Silva, 

1979:322; DeCew and West, 1981:242, figs. 17–34; L. Aguilar-Rosas 

et al., 1982:56; Pacheco-Ruíz and Aguilar-Rosas, 1984:77; HuertaMúzquiz and Mendoza-González, 1985:50; Mendoza-González and 

Mateo-Cid, 1986:424; Scagel et al., 1989:190; R. Aguilar-Rosas et al., 

1990:125; Stewart, 1991:107; Mateo-Cid and Mendoza-González, 

1992:21; Mendoza-González and Mateo-Cid, 1992:19; ServiereZaragoza et al., 1993a:483; R. Aguilar-Rosas and Aguilar-Rosas, 

1994:522; Mateo-Cid and Mendoza-González, 1994b:40; GonzálezGonzález et al., 1996:221, 396; Hernández-Herrera et al., 2005:148.

Ahnfeltiopsis leptophylla (J. Agardh) P. C. Silva et DeCew, 1992:578; Stout 

and Dreckmann, 1993:11.

Algae in clumps, up to 6 cm tall, dark reddish brown; of few 

to several erect, rigid, entangled, slender, branched main axes, 

initially cylindrical to subcylindrical, 0.5 to 1.0 mm wide, becoming compressed to flattened and shorter upward, 0.5–1.25 mm 

wide; dichotomously to subdichotomously branched, up to 5 (or 

more) orders in more or less 1 plane; branch intervals longer in 

lower portions, much less in upper portions; above a spreading, 

discoid attachment base.

Life histories of this species are known to be heteromorphic 

or apomictic (DeCew and West, 1981; Silva and DeCew, 1992). 

Cystocarps initially develop immersed within the branches and, 

later, as they mature, protrude on both sides of surface; vertical 

elliptical in shape, about 900–1000 μm long. Spermatangia in a 

continuous layer, 20–25 μm thick, on surface of upper branches; 

spermatia borne on slender, anticlinally elongated, spermatangial parent cells (after Dawson, 1961b).

Habitat. On rocks and tidal platforms; intertidal.

Distribution. Gulf of California: Punta Chueca 

(Socaaix in the language of the Seri) to Segundo Cerro Prieto, 

Bahía Kino; Isla Pelícanos and Roca Rojo (both in Bahía Kino); 

Nayarit to Jalisco. Eastern Pacific: Alaska to Playa Los Cerritos 

(south of Todos Santos), Baja California Sur; Islas Todos Santos 

(off Ensenada), Baja California; Colima to Michoacán.

Type Locality. Santa Cruz, Santa Cruz County, 

California, USA.

Ahnfeltiopsis serenei (E. Y. Dawson) Masuda

FIGURE 172

Gymnogongrus serenei E. Y. Dawson, 1954a:5, pl. 3: fig. 6; 1954b:441, 

fig. 52d [type specimen]; 1961a:252, pl. 39: fig. 2; 1961b:431; PhạmHoàng, 1969:201, fig. 2.132; Huerta-Múzquiz and Tirado-Lizárraga, 

1970:129; Serviere-Zaragoza et al., 1993a:483; González-González et 

al., 1996:221, 396.

Ahnfeltiopsis serenei (E. Y. Dawson) Masuda, 1993:3, figs. 4–6; Masuda 

et al., 1994:177, fig. 5; González-González et al., 1996:382; Xia 

and Zhang, 1999:102, fig. 60, pl. 5: fig. 5; Serviere-Zaragoza et al., 

2007:9.

Algae of several, cartilaginous, narrow, axes; sparsely, dichotomously branched up to 3 orders; initially terete, 1.0–1.2 

mm in diameter, becoming compressed to flattened upward, 

1.5–2.5 mm wide, 250–350(–400) μm thick; arising from a discoid attachment. Branch surfaces smooth; margins entire; apices 

blunt. Medulla in transection of rounded cells, 30–50 μm in diameter; lowermost portion composed of 14–18 medullary cells, 

upper portions of 10–12 cells; in longitudinal section of elliptical 

cells, with intercellular connections. Cortex in lowermost terete 

portion of 14 (or more) cortical cell layers thick; in upper flattened portions of 3–6 small, more or less rectangular cells, 4–5 

μm in diameter, in anticlinal rows (after Masuda, 1993).

Tetrasporophyte unknown in the Gulf of California. Cystocarps central within medulla, developing outward, becoming hemispherical, 600–800 μm (or more) in diameter; markedly prominent, 

protruding up to 550 μm above blade surface; with multiple carpostomes in thickened cortex of 14–18 anticlinal rows of cells; 

8–10 rows of cells on opposite side. Spermatangia 8–10 μm long, 

2.0–2.5 μm in diameter; within elongated sori on surface of upper 

portion of branches (reproduction after Masuda et al., 1994).

Habitat. On wave-exposed offshore rocks; low 

intertidal.

Distribution. Gulf of California: Cabo San Lucas; 

Nayarit to Jalisco. Eastern Pacific: Isla San Benedicto (Islas Revillagigedo); Oaxaca. Western Pacific: China; Vietnam.

 FIGURE 172. Ahnfeltiopsis serenei: Part of a tufted plant (EYD12058; after Dawson, 1954: pl. 3: fig. 6, as Gymnogongrus serenei). 
NUMBER 96 • 349

Type Locality. On “roches noires” (ryolite rock); 

north end of Con Se Tre Island (Île de Tre), off Nha Trang, 

Khanh Hoa Province, south central Vietnam.

Remarks. Described from south Vietnam, Ahnfeltiopsis serenei has been reported in Pacific Mexico and the southern Gulf of California; it is included since it may occur northward 

in the Gulf. The taxon Gymnogongrus serenei was published 

twice in 1954, first validly published by Dawson (1954a [“17 

September 1954”]) and then again invalidly by Dawson (1954b 

[“October 1954”]).

Gymnogongrus Martius

Gymnogongrus Martius, 1833:27.

Gametophytes are erect, solitary or in clumps, and dichotomously branched (usually in one plane) above a lower terete 

region that usually extends only to the first or second branch 

dichotomy and then becomes subcylindrical to compressed upward; margins are with or without lateral proliferations and are 

attached by a discoid to expansive crustose base. The pseudoparenchymatous medulla is dense, composed of both large and 

small angular cells, often with rounded corners. The cortex consists of radial rows of compacted smaller cells.

Tetrasporangia, where known, are irregularly cruciate and 

found in protruding nemathecial pustules that are scattered and 

usually lateral on branches on the erect gametophytes. The female reproductive apparatus is a procarp consisting of a threecelled carpogonial branch. Cystocarps are globose, embedded in 

the branches, and have more than one ostiole. Spermatangia are 

superficial on the upper branches.

Three species are known in the Gulf of California, including 

one of questionable generic status. 

KEY TO THE SPECIES OF GYMNOGONGRUS IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli somewhat flattened; mostly more or less subdichotomously or sometimes irregularly branched; branches 1.0–1.5 

mm wide, without lateral proliferations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G.? carnosus

1b. Thalli distinctly flattened, with wider branches, 1.5 mm to more than 2 mm in width; with or without lateral proliferations 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Thalli mostly 1.5 mm wide, divaricately, dichotomously branched, mostly from lower portions of branch segments . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. guadalupensis

2b. Thalli dichotomously to subdichotomously branched; branches wider, 2–5 mm in width, with few to numerous simple or 

forked lateral proliferations, up to 1.2 cm long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. johnstonii

Gymnogongrus? carnosus Setchell et N. L. Gardner

Gymnogongrus carnosus Setchell et N. L. Gardner, 1924:745, pl. 22: fig. 1, 

pl. 47a [type specimen]; Dawson, 1944a:299; 1961a:248; 1961b:431; 

González-González et al., 1996:220.

Alga erect, up to 10 cm tall, slightly cartilaginous; purplish 

red, compressed throughout; main axis 3–5 mm wide, irregularly and more or less subdichotomously branched, 3–5 orders; 

branches 2–4(–5) mm wide; above a short stipitate region (to 

about 5 mm long), attached below by a small discoid holdfast. 

Medulla in transection of large, rounded, rectangular to oval, 

thick-walled cells; outward grading into smaller, subspherical 

cells of inner cortex that merge to small, thick-walled cortical 

cells in anticlinal rows of 6–9.

Tetrasporangia and spermatangia unknown. Cystocarps 

relatively small; immersed within frond (after Setchell and Gardner, 1924).

Habitat. Known only from beach drift.

Distribution. Gulf of California: Isla San Pedro 

Mártir.

Type Locality. Cast ashore; Isla San Pedro Mártir, 

Islas de la Cintura, Gulf of California, Mexico.

Remarks. A northern Gulf endemic, Gymnogongus?

carnosus has not again been collected and remains known only 

from the type collection. Setchell and Gardner (1924:745) noted 

that the cell walls of G.? carnosus were of a “very gelatinous 

nature” (“gelatinizing readily in freshwater after drying”) and 

that the “combination of characters of this species” make it uncertain that it is a Gymnogongrus. More collections are needed 

to determine the generic status of G.? carnosus (herein with a 

taxonomic generic query).

Gymnogongrus guadalupensis E. Y. Dawson

Gymnogongrus guadalupensis E. Y. Dawson, 1961a:249, pl. 24: fig. 3, pl. 

45: fig. 1 [type specimen]; 1961b:431; 1966b:64; Stewart and Stewart, 

1984:143; Mendoza-González et al., 1994:107; González-González et 

al., 1996:220.

Algae erect, bushy, of 1 to few branched axes, 4–5 cm tall, 

each becoming compressed to flattened, up to 1.5 mm wide, 

above a short, cylindrical stipe, 2–4 mm long; attached by a 

small discoid holdfast. Branching divaricately, dichotomously at 

intervals of 3–12 mm; become slightly twisted in various planes; 

branches 1.5 mm wide, about 350 μm thick, of more or less uniform width throughout, tending to narrow to 1.0 mm in width in 

ultimate branches, with blunt rounded apices. Medulla of thickwalled, elliptical cells, 45–70 μm in middle of medulla, becoming 

smaller outward, 18–25 μm.

Sporophytes unknown. Cystocarps bulging, elliptical domelike, 0.8–1.0 mm in diameter, about 500 μm tall; scattered on 

axes in middle and upper portions. Spermatangia not known.

Habitat. On rocks and in tide pools; intertidal.

Distribution. Gulf of California: Cabeza Ballena; 

Mazatlán. Eastern Pacific: Isla Guadalupe.
350 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Type Locality. Outer reef and pools; southernmost 

tip of Isla Guadalupe, off Baja California, Pacific Mexico. 

Remarks. Gymnogongrus guadalupensis is reported 

in the southern Gulf. It is included here because of its resemblance to some of the Gulf Ahnfeltiopsis divaricata. More collections are needed to test their relationship and elucidate its 

generic status of the type.

Gymnogongrus johnstonii (Setchell et N. L. Gardner) E. Y. 

Dawson

FIGURE 173

Callophyllis johnstonii Setchell et N. L. Gardner, 1924:746, pl. 51: figs. A,B.

Gymnogongrus johnstonii (Setchell and N. L. Gardner) E. Y. Dawson, 

1954c:294; 1959a:26, fig. 6A; 1961a:250 [in part; excluding “depauperate form”], pl. 43 [larger right specimen only]; 1961b:431; Norris, 

1973:13; Huerta-Múzquiz, 1978:338; Norris, 1985d:212; ServiereZaragoza et al., 1993a:483; Mendoza-González et al., 1994:107; 

González-González et al., 1996:221; Mateo-Cid et al., 2000:65; 

L. Aguilar-Rosas et al., 2000:131; Pacheco-Ruíz and ZertucheGonzález, 2002:468; Serviere-Zaragoza et al., 2007:10; Pacheco-Ruíz 

et al., 2008:209; Bernecker, 2009:CD-Rom p. 63; Fernández-García et 

al., 2011:62.

Algae bushy, up to 25 cm tall, variable in branching and 

size; of few to several erect, complanate branches, 2–4(–5) mm 

wide; attached below by a small pseudoparenchymatous holdfast. Branching somewhat divaricate (much less so in larger 

thalli), much more or less dichotomously or subdichotomously 

branched at 3.0–12 mm intervals, secondary branches pinnate. 

Branches with few to numerous simple to forked lateral branchlets, mostly at 1–2 mm intervals, 3.0–11 mm long. Medulla of 

thick-walled cells, about 100 μm in diameter; subcortex of 3–4 

layers of smaller cells, 20–25 μm in diameter; outer cortex of 

anticlinal rows of branched filaments of 4–5 cells, 5 μm in diameter; inner cells of cortical filament rows spherical, outermost 

cells elongated.

Tetrasporangia within nemathecia up to 1 mm in diameter; 

scattered over blade surface. Cystocarps globose, 700–800 μm 

in diameter, embedded within and bulging on one blade surface; 

scattered throughout upper portions of blade. Spermatangia superficial, covering upper portion of blade surfaces.

Habitat. On rocks; mid intertidal to shallow subtidal.

Distribution. Gulf of California: San Felipe to 

Santa Rosalía; Punta Arena to Cabo Pulmo; Mazatlán, Sinaloa 

to Nayarit. Eastern Pacific: Isla Socorro (Islas Revillagigedo); El 

Salvador; Costa Rica.

Type Locality. Isla de Tortuga, about 24.1 km (15 

miles) northeast of Isla Marcos, off Puerto Santa Rosalía, Baja 

California Sur, Gulf of California, Mexico.

Remarks. Gymnogongrus johnstonii is especially 

abundant in the spring, exhibiting highly variable morphologies. 

The largest specimens of G. johnstonii are quite distinct and are 

mostly found in the central Gulf, particularly on Islas de la Cintura (Midriff Islands).

Petroglossum Hollenberg

Petroglossum Hollenberg, 1943:571, figs. 1–6; Schotter, 1968:75, figs. 46–

50; Abbott, 1969:47.

Algae are erect and may be singular but usually have a few 

to several small, flat, narrow, cartilaginous, ligulate blades arising from a spreading encrusting or stoloniferous base. Each narrow blade is above a short stipe or a very narrowed basal region. 

Blades may be simple (unbranched) or irregularly subdichotomously branched and are with or without lateral or terminal 

proliferations. Medulla is composed of large, thick-walled cells 

and a cortex of one to two layers of smaller cells.

Tetrasporangia are cruciately divided and arranged in distinct anticlinal rows within nemathecia that are single in center 

of a blade. Gametangial structures are usually singular in the 

center of a blade, but cystocarps may also be on short laterals, 

and spermatangia may also be central or toward branch apices. 

Cystocarps are prominent, protruding on both sides of blades, 

with or without an ostiole. Carpospores are in groups that are 

separated by sterile cells. Spermatangial parent cells produce 

spermatangia within sori that are flush with the branch surface. 

One species of Petroglossum is reported in the northern 

Gulf of California.

Petroglossum parvum Hollenberg

FIGURE 174

Petroglossum parvum Hollenberg, 1945:450; Dawson, 1949c:229; 

1961a:244, pl. 40: fig. 2 [type specimens]; 1961b:431; 1966b:64, 

fig. 6D,E; Abbott and Hollenberg, 1976:511, fig. 458; Stewart, 

1991:108; González-González et al., 1996:246; Pacheco-Ruíz and 

Zertuche-González, 2002:468; Pacheco-Ruíz et al., 2008:209.

Algae of small, narrow, ligulate blades, 1–3 cm tall, mostly 

strap-like 2.0–3.0(–4.0) mm wide; simple (unbranched) or divided once dichotomously (or occasionally subdichotomously) 

or rarely divided in threes from upper end; with rounded apices; 

arising from spreading prostrate axes and may also sometimes be 

attached by secondary discs developed along margins of prostrate 

growing blade (Figure 174A,B). A few blades gradually narrowing toward base; some with few short laterals. Internally of few 

cell layers; central portions of blade 180–190 μm thick; medulla 

of 1–2 large cells (Figure 174C,D); subcortex of 1–2 smaller cells; 

outer cortex of single layer of small, pigmented cortical cells.

Reproduction not known in the northern Gulf. Reproductive structures as reported in California (Abbott and Hollenberg, 

1976) occur in center of blades. Tetrasporangia in anticlinal rows 

of 3–5 (Abbott and Hollenberg, 1976: fig. 458), within small 

rounded nemathecia, usually 1 per blade, protruding from both 

surfaces. Cystocarps with small, single ostiole. Spermatangia in 

small rounded, nemathecia.

Habitat. On rocks, pebbles, coralline rubble, and 

debris; subtidal, 13–18 m depths.

Distribution. Gulf of California: Isla Salsipuedes 

(NW of Isla Las Ánimas), Islas de San Lorenzo (SW Islas de la 
NUMBER 96 • 351

FIGURE 173. Gymnogongrus johnstonii, two thalli to show variation in density of spinulose branchlets: A. Specimen bearing a few short, lateral, spinulose branchlets (JN-6205, US Alg. Coll.-159912). B. Specimen with numerous spinulose branchlets (JN-5736, US Alg. Coll.-159906). 
352 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Cintura). Eastern Pacific: Santa Barbara to Laguna Beach, California; Isla Cedros, Baja California.

Type Locality. Intertidal; Laguna Beach, Orange 

County, southern California, USA.

Remarks. The subtidal Gulf specimens of Petroglossum parvum are thicker, 180–190 μm, but of only 1–2 layers of 

very large medullary cells in transection, whereas those of the 

intertidal southern California specimens are thinner, 60–120 μm 

thick, with 3–4 layers of comparatively smaller medullary cells. 

Once reproductive specimens are found in the Gulf of California, 

they can be compared morphologically and molecularly to type 

locality specimens.

Solieriaceae

Solieriaceae J. Agardh, 1876:502.

Algae of this family are mostly erect and usually large, cylindrical, compressed, flattened or foliose, and simple, branched, 

or lobed, attached by a discoid to crustose holdfast. One genus 

is a minute parasite. Thalli are multiaxial in construction with 

secondary pit-connections between adjacent cells. The medulla is 

composed of loose to dense parallel longitudinal filaments, surrounded by a subcortical layer of large cells, which grade into 

successively smaller, usually stellate cells outward to the outer 

cortex, which is composed of files of small cells at right angles 

to the axis.

Life histories are triphasic, with isomorphic gametophytes 

and sporophytes. Tetrasporangia are zonate, developed from 

outer cortical cells, and scattered over the thallus surface. 

Carpogonial branches are three (to four) celled, scattered and 

borne on large supporting cells in the inner cortex. Carpogonial 

branches are on separate cortical branches from auxiliary cells. 

Auxiliary cells are also scattered and borne in a similar location. 

The auxiliary cell systems can be identified prior to or aften 

diploidization (Guimarães and Oliviera, 1996). Cells surrounding auxiliary cells divide prior to gonimoblast development, and 

the gonimoblast filaments, at least at first, grow inward into 

the medulla. Cystocarps have large central fusion cells or a center of small-celled vegetative tissue and are embedded within or 

protruding from thallus surface, with a pericarp and an ostiole. 

Carposporangia develop from most or only distal gonimoblast 

cells. Spermatangia are in sori on thallus surface or in isolated 

clusters.

Remarks. There are also two genera of the Solieriaceae, both minute and parasitic: Gardneriella Kylin (1941) and 

Tikvahiella Kraft et P. W. Gabrielson (1983). Gardneriella tubifera Kylin on Sarcodiotheca gaudichadii is recorded in the eastern Pacific from central California to northern Baja California 

(Dawson, 1961a; Goff and Hommersand, 1982; Pacheco-Ruíz 

and Aguilar-Rosas, 1984).

Four macrophyte genera of the Solieriaceae are found in the 

northern Gulf of California.

FIGURE 174. Petroglossum parvum: A, B. Habit variation (EYD-26138, US Alg. Coll.-78080). C. Transection through blade. D. Transection 

through thallus margin (C, D, EYD-26138, US Alg. Coll. microscope slide 783).
NUMBER 96 • 353

KEY TO THE GENERA OF SOLIERIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Axes and branches compressed to flattened . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sarcodiotheca (in part)

1b. Axes and branches terete to slightly compressed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Thallus terete to slightly compressed, wiry; less than 250 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . Wurdemannia

2b. Thallus terete, turgid to cartilaginous; much wider in diameter, greater than 1.0 mm (mostly 2–7 mm) . . . . . . . . . . . . 3

3a. Axes and branches with numerous conspicuous short spinose or spur-like protuberances on most surfaces; broader, 

4–7(–10) mm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tacanoosca

3b. Axes and branches, 1–4 mm in diameter; with smooth surfaces (without spinose or spur-like protuberances); often with 

short lateral branchlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Axes narrow, mostly less that 2 mm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Agardhiella

4b. Axes wider, mostly 2–4 mm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sarcodiotheca (in part)

Agardhiella F. Schmitz

Agardhiella F. Schmitz in Schmitz et Hauptfleisch, 1896:371; Gabrielson and 

Hommersand, 1982:46.

Algae are erect, with one to many terete to slightly compressed axes, radially, distichously, unilaterally, or irregularly 

branched, and attached below by a discoid holdfast. Medulla is 

composed of parallel longitudinal filaments. Cortex is composed 

of rounded or angular, large cells in the inner cortex, which outwardly become successively smaller toward the surface. 

Tetrasporangia are zonately divided, embedded in the cortex and scattered over branch surfaces. Cystocarps are large, embedded in the cortex and protruding beyond the branch surface, 

and are internally composed of a group of sterile cells, with the 

carposporangia formed in a ring at the periphery. Spermatangia 

are in small sori on branch surfaces. 

One endemic species of Agardhiella is found in the northern 

Gulf of California. 

Agardhiella mexicana E. Y. Dawson

Agardhiella mexicana E. Y. Dawson, 1944a:288, pl. 69: fig. 1 [type collection]; González-González et al., 1996:168.

Agardhiella tenera sensu Dawson, 1961a:231 [in part; Gulf of California 

specimens only], pl. 34, fig. 1 [non Agardhiella tenera (J. Agardh) 

Schmitz in Schmitz et Hauptfleisch, 1897a:371, which is now Agardhiella subulata (C. Agardh) Kraft et M. J. Wynne, 1979:329; see also 

Gabrielson, 1982:93; Gabrielson, 1985:278].

Algae erect, of 1 to few terete, branched axes, up to 15 cm 

tall; slender, 1.0–1.5(–2) mm in diameter; branching irregularly 

more or less radially, 2–4(–5) orders, branches with acute apices; 

ultimate branchlets short, sometimes spine-like in appearance; 

arising from a small discoid holdfast. Medulla a small central 

core of longitudinal filaments; surrounded by large isodiametric 

cells, grading outward into cortex of small pigmented cells.

Tetrasporangia zonately divided, 15–25 μm in diameter, 

borne in cortical layers below surface, scattered over branches. 

Cystocarps and spermatangial thalli unknown.

Habitat. On rocks or shells, often partially covered 

by sand or fine sediment; low intertidal to shallow subtidal, 4–12 

m depths (also dredged from 22–80 m depths).

Distribution. Gulf of California: Bahía La Choya 

(Bahía Cholla, northwest of Puerto Peñasco); Isla Ángel de la 

Guarda to Bahía San Luis Gonzága.

Type Locality. Dredged from 4 m depth; south 

shore of Puerto Refugio, Isla Ángel de la Guarda (Islas de la 

Cintura), Gulf of California, Mexico.

Remarks. Apparently endemic to the Gulf of California, Agardhiella mexicana remains a little-known species. In 

the upper Gulf, growth forms of those from Bahía La Choya 

(vicinity of Puerto Peñasco) were noted by Dawson (1966a, as 

“A. tenera”) to be the same as those he previously treated as 

A. mexicana (Dawson, 1944a).

Some investigators have followed Dawson (1961a:231, as 

“Agardhiella tenera,” now conspecific with A. subulata Kraft et 

M. J. Wynne, 1979) in considering the northern Gulf of California A. mexicana to be conspecific with those of the Pacific 

coast of North America that have been referred to “Agardhiella 

coulteri” and “Neoagardhiella baileyii” (e.g., Wynne and Taylor, 

1973; Abbott and Hollenberg, 1976; Kraft and Wynne, 1979), 

but those taxa are currently recognized to be Sarcodiotheca 

gaudichaudii (Montagne) P. W. Gabrielson (1982).

However, on the basis of differences in the size of axes and 

branch diameters, the degree of branching, and the smaller tetrasporangia sizes, the Gulf Agardhiella mexicana appears to be a 

separate species from Sarcodiotheca gaudichaudii. Specimens of 

Mendoza-González and Mateo-Cid (1986, as “Neoagardhiella 

baileyi”) from Guaymas need to be reexamined to see if they are 

possibly referable to A. mexicana or S. gaudichaudii.

Studies on the development of vegetative and reproductive 

structures of the Gulf A. mexicana, particularly on cystocarpic 

material, along with molecular phylogenetic analyses are necessary before its taxonomic status and relationship to other species 

can be understood.

Sarcodiotheca Kylin

Sarcodiotheca Kylin, 1932:15.

Algae are erect, with one or more terete, compressed, or 

flattened blades, attached by a discoid holdfast. Branching is 

regularly or irregularly dichotomous and occasionally with 
354 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

proliferous branchlets. Branches are terete, compressed, or flat, 

gradually narrowing upward, with blunt or subacute tips. The 

medulla is composed of slender medullary filaments. The cortex 

is of large, colorless parenchymatous cells into the inner cortex 

and two to three outer layers of smaller, pigmented cells toward 

the thallus surface.

Tetrasporangia are zonately divided and borne in the outer 

cortex, scattered over the blade. Cystocarps project from branch 

surfaces and have a pericarp. Spermatangia are in irregularly 

shaped sori, superficial and scattered over the blade surface. 

Five species of Sarcodiotheca are recognized from the northern Gulf of California; two are newly reported in the Gulf. 

KEY TO THE SPECIES OF SARCODIOTHECA AND AGARDHIELLA IN THE NORTHERN GULF OF CALIFORNIA

1a. Axes and branches terete, branched irregularly alternately, more or less radially . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Thalli compressed to markedly flattened . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2a. Terete axes and branches, 2–4 mm in diameter; branches constricted at base; tetrasporangia 40–42 μm in diameter . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sarcodiotheca gaudichaudii

2b. Terete axes and branches more slender, 1–1.5(–2) mm in diameter; tetrasporangia smaller, 15–25 μm in diameter . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Agardhiella mexicana

3a. Blades mostly 2–7 mm wide; repeatedly dichotomously branched, margins smooth or at times with marginal proliferations; cystocarps predominately marginal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sarcodiotheca dichotoma

3b. Blades mostly wider, compressed to flattened; cystocarps scattered over surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Thalli compressed; branching irregularly dichotomous or more or less alternate, pinnate, or opposite; up to 8 mm wide 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sarcodiotheca taylorii

4b. Flattened, dichotomously or irregularly branched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

5a. Primary blades narrow, 2–6 mm wide, irregularly branched at wide intervals, 2–3(–5) times . . . . . . Sarcodiotheca linearis

5b. Primary blades wider, over 1 cm (up to 3.0 cm) in width; dichotomously branched, 5–7 times . . . . Sarcodiotheca furcata

Sarcodiotheca dichotoma (M. Howe) E. Y. Dawson

FIGURE 175

Anatheca dichotoma M. Howe, 1911:502, pl. 29. 

Sarcodiotheca dichotoma (M. Howe) E. Y. Dawson, 1944a:290; 1961a:226, 

pls. 28, pl. 31: fig. 4; 1961b:427; Norris, 1973:12; Gabrielson, 1982:75, 

figs. 2–5, 8, 11–13, 16, 18, 20, 22, 23, 27; González-González et al., 

1996:268; Bula-Meyer and Norris, 2001:356: figs. 7–8; CONANP, 

2002:140; Pacheco-Ruíz and Zertuche-González, 2002:468; PachecoRuíz et al., 2008:208.

Thalli erect, of 1 to few complanate dichotomously branched 

blades, to 15 cm tall or more, cuneate below to a short stipe, with 

a small discoid holdfast. Blades much branched in 1 plane, with 

5–11 dichotomous divisions, branch angles narrow to divaricate; 

0.3–1.3 mm thick, 2–7(–12) mm wide, tapering upward to forked 

ultimate divisions, to 1.0 mm wide; acuminate apices often conical 

terete; margins smooth and entire or often with numerous lateral 

proliferations. Medulla of central linear filaments, 10–20 μm in 

diameter, between large, thick-walled cells, mostly 2 layered, to 

340 μm thick, these in turn abruptly adjoined to outer 2-layered 

cortex of small pigmented cells, 7–10 μm in diameter.

Tetrasporangia zonate, ovoid, 50–85 μm long; borne in unmodified cortex, scattered over blade. Cystocarps dome shaped, 

1.3–2.0 mm in diameter; mostly restricted to blade margins or 

occasionally over middle portion of blade surface. Spermatangia 

not seen in Gulf material. 

Habitat. On rocks; shallow subtidal down to 30 m 

depths. 

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda to Isla San Esteban (Islas de la Cintura); 

El Desemboque to Bahía San Carlos; Isla La Ventana, Bahía de 

Los Ángeles; Puerto Escondido; Isla Carmén; Canal de San Lorenzo (off southern end of Isla Espíritu Santo); La Paz. 

Type Locality. Vicinity of La Paz, Baja California 

Sur, Gulf of California, Mexico. 

Remarks. Sarcodiotheca dichotoma has also been 

reported in the Western Atlantic from Tobago (Taylor, 1962, as 

Sarcodiotheca caribaea W. R. Taylor; Wynne, 2011) and Caribbean Colombia (Bula-Meyer and Norris, 2001:356, figs. 7–8). 

On a morphological basis these seem to be one species; however, molecular comparisons of type localitiy materials of Gulf 

of California S. dichotoma and Western Atlantic S. caribaea and 

S.dichotoma are needed to test their relationships.

Sarcodiotheca furcata (Setchell et N. L. Gardner) Kylin

FIGURES 176, 177

Anatheca furcata Setchell et N. L. Gardner, 1903:310, pl. 23: fig. 39, pl. 24: 

fig. 41; Kylin, 1925:36, figs. 20, 21. 

Sarcodiotheca furcata (Setchell et N. L. Gardner) Kylin, 1932:16; Dawson, 

1961a:229, pl. 30: figs. 1, 2, pl. 31: figs. 1, 4; 1961b:427; Hollenberg 

and Abbott, 1966:85, fig. 36; Abbott and Hollenberg, 1976:488, fig. 

432; Gabrielson, 1982:75, figs. 1, 6, 7, 9, 10, 14–15, 17, 19, 21, 24–26, 

28; Stewart, 1991:100; Serviere-Zaragoza et al., 1993a:484; GonzálezGonzález et al., 1996:268; Pacheco-Ruíz and Zertuche-González, 

2002:468; Pacheco-Ruíz et al., 2008:209; Fernández-García et al., 

2011:64. 

Algae erect, complanate; of repeatedly, dichotomously 

branched blades, up to 37 cm tall; arising from a slender, cylindrical stipe, 1–2 cm in length; attached to substrate by a discoid holdfast. Blade branched in 1 plane, 5–7 times; dichotomies 

cuneate; segments 1.0–2.5(–3.0) cm wide, up to 1.0 mm thick 
NUMBER 96 • 355

when fresh; margins entire or with short proliferations or with 

few to numerous short to long laterals; terminal portions attenuated to subacute tips. Central medulla of interlaced filaments, 

surrounded on each side by 2–3 layers of large, isodiametric 

cells, up to 70 μm diameter. Cortex of 2 layers of small cells; 

pigmented cortical cells to 10 μm in diameter.

Tetrasporangia zonately divided, 70–80 μm long; scattered 

over thallus surface. Cystocarps dome shaped and protruding, 

1–4 mm in diameter; scattered over thallus surface. Spermatangia in irregularly shaped sori, forming minute whitish mottled 

areas on blade surface. 

Habitat. On rocks and shells; shallow subtidal, 3.3–

22.7 m depths. 

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda; Isla San Esteban; Punta La Gringa, 

Bahía de Los Ángeles; Ensenada Grande (Bahía San Pedro, between Bahía San Carlos and Tastiota); Nayarit to Jalisco; Isla 

María Magdalena (Islas Marías; Islas Tres Marías). Eastern Pacific: southern Alaska to Washington; southern California; Costa 

Rica.

 Type Locality. West coast of Whidbey (Whidby) 

Island, Island County, Puget Sound, Washington, USA. 

FIGURE 175. Sarcodiotheca dichotoma: A. Habit. B. Habit; note cystocarps borne mostly along blade margins (A, B, JN-4432, US Alg. Coll.-

160847). C. Habit (JN-6554, US Alg. Coll.-160887). 
356 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 176. Sarcodiotheca furcata: Habit (JN-5328, US Alg. Coll.-160855). 
NUMBER 96 • 357

FIGURE 177. Sarcodiotheca furcata: A. Thallus with numerous short proliferations and short to long laterals (JN-5349, US Alg. 

Coll.-160859). B. Female gametophyte with cystocarps on thallus surface and along margins (JN-5798, US Alg. Coll.-160864). 

C. Transection of cystocarp, with large sterile cells at center, surrounded by masses of carpospores in groups (after Setchell and 

Gardner, 1903: pl. 24: fig. 41).
358 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Remarks. A new distribution record, specimens of 

Sarcodiotheca furcata (US Alg. Coll.) from Puerto Refugio, Isla 

Ángel de la Guarda, establish it in the Gulf of California. It is 

distinguished from the other species of Sarcodiotheca in the Gulf 

by its larger size, deep red color, and broad, flattened, dichotomously branched blades with forked tips. In the northern Gulf, 

S. furcata is found only off some islands of Islas de la Cintura 

and apparently from drift at Ensenada Grande. Locally, at some 

locales, e.g., Puerto Refugio, Isla Ángel de la Guarda, it can be 

a conspicuous species in the subtidal flora. Although S. furcata

is known from Alaska to the submarine La Jolla Canyon, southern California, it has not been found in Pacific Baja California 

(Stewart, 1991).

A resemblance of northern Washington S. furcata to the Gulf 

of California S. elongata (Setchell et N. L. Gardner) Setchell in 

E. Y. Dawson (1944a:289) was previously mentioned by Setchell 

and Gardner (1924, as Anatheca elongata Setchell et N. L. Gardner, 1924:747, pl. 64) in their original description. Although 

Dawson (1961a) later placed S. elongata in synonymy with another species, S. dichotoma, this seems to be incorrect. The type 

of S. elongata (type locality: Isla San Pedro Mártir) more closely 

agrees with our Gulf specimens referred to S. furcata. The relationship of Pacific northwest S. furcata and the northern Gulf

S. elongata needs to be further comparatively tested, and their 

taxonomic status and relationship need to be elucidated. If different from S. furcata, the northern Gulf specimens could possibly be S. elongata.

Sarcodiotheca gaudichaudii (Montagne) P. W. Gabrielson

FIGURE 178

Gigartina gaudichaudii Montagne, 1842a:255; 1846a:69, pl. 143: fig. 1. 

Sarcodiotheca gaudichaudii (Montagne) P. W. Gabrielson, 1982:93, figs. 

1–21; Scagel et al., 1989:257; Stewart and Stewart, 1984:144; Stewart, 

1991:101; Ramírez and Santelices, 1991:292; R. Aguilar-Rosas and 

Aguilar-Rosas, 1994:522; González-González et al., 1996:268; AnayaReyna and Riosmena-Rodríguez, 1996:864, tbl. 1; Hoffmann and 

Santelices, 1997:310, fig. 83; Pacheco-Ruíz and Zertuche-González, 

2002:468; Pacheco-Ruíz et al., 2008:209. 

Neoagardhiella gaudichaudii (Montagne) I. A. Abbott, 1978:52. 

Agardhiella gauichaudii (Montagne) P. C. Silva et Papenfuss in Silva, 

1979:321.

Agardhiella coulteri sensu Kylin, 1941:18; Smith, 1944:260, pl. 62: fig. 4 

[non Agardhiella coulteri (Harvey) Setchell in Collins et al., 1897: 

Exsiccate no. 333; basionym: Hypnea coulteri Harvey in Harvey and 

Bailey, 1851:371, as “Hypriea coulteri”; =Rhabdonia coulteri (Harvey) 

Harvey, 1853:154, pl. 23: fig. B; =Neoagardhiella coulteri (Harvey) 

P. C. Silva, 1981:487]. 

Agardhiella tenera sensu Dawson, 1944a:288; 1961a:231 [in part; excluding Gulf of California specimens of Agardhiella mexicana]; Gabrielson, 

1985:275 [non Agardhiella tenera (J. Agardh) F. Schmitz in Schmitz 

and Hauptfleisch, 1897a:371, basionym: Gigartina tenera J. Agardh, 

1841:18, which is now Agardhiella subulata (C. Agardh) Kraft et M. J. 

Wynne, 1979:329, basionym: Sphaerococcus subulatus C. Agardh, 

1822:328].

Neoagardhiella baileyi sensu Abbott and Hollenberg, 1976:483, fig. 428 

[non Neoagardhiella baileyi (Kützing) Wynne et Taylor, 1973:101, basionym: Rhabdonia baileyi Kützing, 1866:26, which is now Agardhiella 

subulata (C. Agardh) Kraft et M. J. Wynne, 1979:329]. 

Algae of 1 or more terete axes, up to 20 cm tall, up to 4 

mm in diameter, very variable in habit morphology; branching 

sparse to dense, irregularly distichous or radial, mostly of only 

1 order, occasionally 2(–3) orders; branches of varying length, 

often constricted or narrowed at base, and with acute upper 

tip; attached by a discoid holdfast. Medulla a central core of 

longitudinal filaments; surrounded by large cells that become 

progressively smaller toward the outer cortical layer of small 

pigmented cells.

Tetrasporangia zonately divided, about 70 μm long, 

40–42 μm in diameter; borne in outer cortex. Carpogonial 

branches of 3 cells, developing in inner cortex. Cystocarps 

1–2 mm in diameter, with an ostiole; prominently protruding 

above thallus surface. Gonimoblast with a central mass of sterile 

cells, bearing carposporangia terminally. Spermatangia in small 

patches on surface, often converging and becoming continuous 

on upper branches.

Habitat. On rocks and shells and partially sandcoved hard substratum; low intertidal to shallow subtidal, down 

to 15 m depths.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda to Ensenada de San Francisco; Bahía 

Agua Verde to Punta Los Frailes. Eastern Pacific: Alaska to Baja 

California Sur; Isla Clarión (Islas Revillagigedo); Peru; Chile.

Type Locality. Paita (seaport on south side of 

Bahía de Paita), Paita Province, northwestern Peru.

Remarks. Following the single species concept, Abbott (1978) found the correct species name for Pacific coast material referred to as “Agardhiella coulteri” and “Neoagardhiella 

baileyii” to be Neoagardhiella gaudichaudii (Montagne) I. A. 

Abbott (=Agardhiella gaudichaudii Silva et Papenfuss in Silva, 

1979:321). Subsequently, Gabrielson (1982) showed Agardhiella gaudichaudii to belong to Sarcodiotheca, as S. gaudichaudii (Montagne) P. W. Gabrielson, an eastern Pacific species now 

known from southern Alaska to central Baja California, Peru 

and Chile, and the Galápagos Islands. 

Sarcodiotheca linearis Setchell et N. L. Gardner

Sarcodiotheca linearis Setchell et N. L. Gardner, 1937:80, pl. 5: fig. 12a,b, pl. 

15: fig. 35; Dawson, 1944a:289; 1961a:228, pl. 30: fig. 3; 1961b:427; 

Stewart and Stewart, 1984:144; González-González et al., 1996:268.

Algae erect, up to 10 cm tall; of narrow, flat, strap-like 

blades, 2–6 mm wide, 400–500 μm thick; irregularly branched 

to 2–3(–5) orders, branching at relatively widely separated intervals; ligulate blades gradually expanding above a short, terete 

stipe, 1–2 mm long, attached below by a small discoid holdfast. 

Medulla with a middle linear core of narrow, interlaced filaments between large, parenchymatous medullary cells that become smaller outward in subcortex. Outer cortex of 2–3 layers 

of small, slightly radially elongated, pigmented cells.
NUMBER 96 • 359

FIGURE 178. Sarcodiotheca gaudichaudii: A. Habit (JN-5439, US Alg. Coll.-160874). B. Male gametophyte (JN-5439, US Alg. Coll.-

160875). C. Female gametophyte (JN-6555, US Alg. Coll.-160877).
360 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Tetrasporangia 25–60 μm in diameter; scattered over surface. Cystocarps embedded within and protruding from both 

sides of blade surfaces. Spermatangia colorless, elongated; scattered over both blade surfaces.

Habitat. On rocks; subtidal, 4–30 m depths (also 

dredged from 65–95 m depths).

Distribution. Gulf of California: Isla Tiburón; 

Bahía de San Lucas. Eastern Pacific: Isla Guadalupe (off Baja 

California); Punta Entrada, Isla Magdalena to Punta Gorda 

(Baja California Sur). 

Type Locality. Bahía de San Lucas, southern end 

of Baja California Sur, Gulf of California.

Remarks. Although recognizing Sarcodiotheca linearis in the southern Gulf, Dawson (1961a:229) was tentative in 

referring a northern Gulf specimen from off the southern end of 

Isla Tiburón to S. linearis. Thus, confirmation of S. linearis in the 

northern Gulf must await further collections. 

Sarcodiotheca taylorii E. Y. Dawson

FIGURE 179 

Sarcodiotheca taylorii E. Y. Dawson, 1961a:227, pl. 29; 1961b:427; ServiereZaragoza et al., 1993a:484; González-González et al., 1996:268; 

Pacheco-Ruíz and Zertuche-González, 2002:468; Pacheco-Ruíz and 

Zertuche-González, 2002:468; Pacheco-Ruíz et al., 2008:209. 

Gracilaria pinnata sensu Taylor, 1945:232 [non Gracilaria pinnata Setchell et 

N. L. Gardner, 1924:751].

Thalli erect, compressed, to 14 cm tall, and up to 8(–12) mm 

wide, irregularly to alternately branched in 1 plane from a more 

or less indistinct main axis; basal attachment unknown. Frond 

with entire margins; upper portions gradually attenuated; tips 

subulate in profile. Central medulla of slender filaments, about 9 

μm in diameter; outer medulla of 3–4 layers of large isodiametric 

cells, 80–120 μm in diameter. Cortex composed of 2 layers of 

small cells; inner cortical cells 11–30 μm in diameter, outer cortical cells to 10 μm diameter.

Tetrasporangia zonate, 80–90 μm long, to 60 μm wide, scattered over thallus surface. Cystocarps dome shaped, up to 1 mm 

in diameter, scattered over thallus. Spermatangia not known. 

Habitat. On rocks, often partially sand covered; 

subtidal, 12–15 m depths. 

Distribution. Gulf of California: Isla Estanque; 

Isla la Ventana, Bahía de Los Ángeles; Punta Los Frailes; Nayarit 

to Jalisco; Isla María Magdalena (Islas Marías).

Type Locality. Isla María Magdalena (Islas 

Marías; Islas Tres Marías), off Nayarit, Mexico.

Tacanoosca J. N. Norris, P. W. Gabrielson 

et D. P. Cheney, gen. nov.

Latin Diagnosis. Algae teretes axes cum ramis 

plerumque radialnus et bilateralibus, et iota carrageenan ferentes. Cystocarpiis magnis, prominentibus latus secundum axes 

FIGURE 179. Sarcodiotheca taylorii: A. Female gametophyte (JN-4460a, US Alg. Coll.-160878). B. Tetrasporophyte (JN-4460b, US Alg. Coll.-

160879).
NUMBER 96 • 361

ramus, vel prope basim ferri vel ramulis spinosis; pseudoparenchymatous in central sterilis tissue egens gonimoblast filamentis 

ca. Carposporangia produci sine cella confusionem, que vectus 

filamentis sterilibus botri in thalamis. Medulla axial constituendi rhizoideas coro (mediam, funis compactum litore filamentis longitudinalibus) ut cingitur cellulis pseudoparenchymatous 

qui fiunt successive ad exteriora minora cortex tenuis cellulis. 

Zonate tetrasporangiis cum utraque utrumque proprie Tetradis 

minores haereret corticem et ramos passim. Sori in spermatangia 

in ramo superficies.

Algae are erect, cartilaginous, terete; of axes that bear 

branches radially to bilaterally, attached below by a discoid holdfast. Axes and branches often beset with numerous papillae or 

spinose protuberances. One or more of these initially determinate 

spines may develop an indeterminate branch. Medulla composed 

of an axial core of rhizoids (a central cable-like strand of compacted longitudinal filaments) that is surrounded by pseudoparenchymatous cells, which become progressively smaller outward to a 

cortex of small cells. Species produces iota carrageenan.

Tetrasporangia zonate, with the two ends of each tetrad 

distinctively smaller; embedded in the cortex and scattered over 

the branches. Cystocarps large, protruding laterally along the 

branch axes, and/or borne basally near or on spinose branchlets; 

with a central pseudoparenchymatous, sterile tissue and lacking 

gonimoblast filaments. Carposporangia produced in the absence 

of a fusion cell and borne in clusters with sterile filaments within 

chambers. Spermatangia are in sori, on branch surfaces. 

Generic Type. Tacanoosca uncinata (Setchell et 

N. L. Gardner) J. N. Norris, P. W. Gabrielson et D. P. Cheney 

(herein). 

Etymology. The generic name we have chosen, 

Tacanoosca, is based on using a Latin form of the Seri language 

name for this species, taca-noosc (Norris, 1991:211). In choosing their name, we honor the Seri (Comcáac; “the People”) of 

Sonora (Felger and Moser, 1973, 1991; Bowen, 1983) and their 

knowledge of northern Gulf of California seaweeds (Norris, 

1991). 

Remarks. Most of the genera related to Tacanoosca, i.e., Eucheuma J. Agardh (1847:16), Kappaphycus Doty 

(1988:159, 171), and Betaphycus Doty (1995:237; see also Silva, 

et al., 1996a:326, 919), produce kappa carrageenan and iota carrageenan, natural products of commercial value that are extensively utilized by the food and other industries (Chapman and 

Chapman, 1980; Abbott and Cheney, 1982; Doty and Norris, 

1985; Doty, 1988; Santos, 1989; Zertuche-González et al., 1993). 

The Gulf of California Tacanoosca produce an iota carrageenan 

(Dawes et al., 1977); although of economic potential (ZertucheGonzález, 1994, 1996; Zertuche-González et al., 2006), T. uncinata has been only occasionally harvested and is not presently 

being exploited (Robledo and Freile-Pelegrín, 2011). 

Barilotti and Zertuche-González (1990, as Eucheuma uncinatum) concluded that commercial harvesting would have 

significant effects on the natural populations and should not be 

attempted until spore propagation can be provided as part of 

resource management. Up until recently, efforts to produce this 

apparent annual species consistently in commercial quantities 

have been largely unsuccessful (Parker, 1974; Doty and Norris, 

1985). More recent work has focused on its vegetative propagation from tissue and calluses (Gibor et al., 1981; Polne-Fuller 

and Gibor, 1986a, 1986b, 1987) and culture in tanks (Polne et 

al., 1980, 1981; Zertuche-González et al., 1987, 1993). Successful techniques for its cultivation in tanks were developed by 

Zertuche-González (1988, 1990); these aquaculture methods 

should take the strain off the need for field harvesting. 

There is one known species, originally described from the 

northern Gulf of California.

Tacanoosca uncinata (Setchell et N. L. Gardner) J. N. Norris, 

P. W. Gabrielson, et D. P. Cheney, comb. nov.

FIGURES 8C, 180

Eucheuma uncinatum Setchell et N. L. Gardner, 1924:748, pls. 67, 

68; Dawson, 1944a:288; 1961a:230, pl. 32; 1961b:427; Guzmán 

del Próo, 1969:689; Norris, 1973:11; Lawson et al., 1973:2177; 

Dawes et al., 1977:437; Huerta-Múzquiz, 1978:337; Polne et al., 

1980:115; Polne et al., 1981:619; Norris, 1985a:63, figs. 1–6; Doty 

and Norris, 1985:55–56; Norris, 1985d:211, fig. 16.5; ZertucheGonzález et al., 1987:1; Doty, 1988:182, figs. 19D, 20; Dreckmann 

et al., 1990:27; Zertuche-González et al., 1993:601; GonzálezGonzález et al., 1996:201; Riosmena-Rodríquez et al., 1998:28; 

L. Aguilar-Rosas et al., 2000:131; Pacheco-Ruíz and ZertucheGonzález, 2002:468; Schubert et al., 2006:1208; Pacheco-Ruíz et 

al., 2008:210. 

Eucheuma johnstonii Setchell et N. L. Gardner, 1924:748, pl. 25: fig. 42, 

pls. 65, 66. 

Algae erect, cartilaginous, and cylindrical, freely branched 

throughout, up to 50 cm tall; attached by a discoid to conical 

holdfast. Primary axes, (3–)4–7(–10) mm in diameter; abundantly branched, up to 3(–4) orders, with slender, often long, 

branches with acute apices; axes and branches sparsely to densely 

beset with simple or branched, short spinose proliferations.

Tetrasporangia borne in slightly modified cortex, scattered 

over thallus; tetrasporangia zonately divided, 70–90 μm long, up 

to 33 μm wide, with the 2 end spores greatly reduced in size (see 

Setchell and Gardner, 1924, pl. 25: fig. 24). Cystocarps prominent, subspherical, large, 1.0–1.4 mm in diameter; either single 

or grouped and spread out on the thallus; borne directly on the 

axes and branches or often near base of short lateral (spinose) 

proliferations or on the spines toward the upper ends. Spermatangia narrowly elongate, anticlinally arranged in irregularly 

shaped superficial sori, on branch surfaces and proliferations; 

spermatia 2.5–3.0 μm in diameter. 

Habitat. On rocks; low intertidal to shallow subtidal, down to 12 m depths. 

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas (Sonora); Puerto Refugio, Isla Ángel de la Guarda; 

Isla San Perdo Mártir; El Coloradito to Bahia San Francisciquito 

(Baja California); Mazatlán, Sinaloa to Jalisco. Eastern Pacific: 

Colima to Puerto Galera, Oaxaca.
362 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 180. Tacanoosca gen. nov., habit variation in T. uncinata: A. Male gametophyte (EYD-1800a, US Alg. Coll.-7181). B. Tetrasporophyte (JN-238, US Alg. Coll.-89992). C. Thallus with spinose laterals and holdfast (arrow) (JN-5415, US Alg. Coll.-210494). 

D. Female gametophyte with protuberant cystocarps (EYD-1800b, US Alg. Coll.-7181).
NUMBER 96 • 363

Holotype. I.M. Johnston-86 (Eucheuma uncinatum Setchell et N. L. Gardner, CAS, now UC; isotype: US Alg. 

Coll.-56407). 

Type Locality. On rocks; Isla Las Ánimas (Isla San 

Lorenzo del Norte), Islas de San Lorenzo, southwestern Islas de 

la Cintura, Gulf of California, Mexico. 

Remarks. Tacanoosca uncinata is considered to be 

an annual species. Small, juvenile thalli were observed in the 

late fall and winter (Dawson, 1961a), and the largest sizes were 

observed in late spring to midsummer. Stands of T. uncinata in 

Bahía de Los Ángeles underwent a huge reduction in standing 

crop in the fall, but some living thalli could be found year-round 

(Zertuche-González, 1988). As currently interpreted, Tacanoosca uncinata exhibits a bewildering array of morphological 

forms (see Norris, 1985a: figs. 1–6). Molecular analyses of these 

different morphological forms, including the Gulf described Eucheuma johnstonii, in comparison with the type of T. uncinata, 

will test if it is a single broadly defined species, or possibly more 

than one taxon. For example, rbcL analysis of Fredericq et al. 

(1999) found a Gulf specimen of “E. uncinatum” to group with 

some species of Sarcodiotheca, suggesting the possibility of more 

species to be elucidated.

The Puerto Peñasco specimens cited by Dawson (1966a:23,

as “Eucheuma uncinatum”) and a more recent specimen (US Alg. 

Coll.) collected in beach drift from Playa Las Conchas (Playa Estación), vicinity of Puerto Peñasco, have been reexamined and 

found not to be T. uncinata; they probably represent an undescribed species of Gracilaria in the upper Gulf. 

Wurdemannia Harvey

Wurdemannia Harvey, 1853:245.

Algae are erect, forming tufts, entangled turfs, or spreading 

mats, and composed of slender, wiry, terete, irregularly branched 

axes, less than 300 μm in diameter, arising above entangled rhizomatous axes that attach to substratum. Secondary attachments 

may develop between branches and the lower prostrate axes. 

Thalli are multiaxial and nearly pseudoparenchymatous in transection. Medulla has a central core of dense, elongate (longitudinally), thin-walled medullary cells that outwardly become shorter 

and thicker walled to the cortical layer. Cortex is usually one layer 

(occasionally more) of small, rounded, thick-walled cortical cells.

Tetrasporangia are zonately divided and grouped in slightly 

swollen tips of fertile axes. Cystocarpic and spermatangial thalli 

are unknown. 

Remarks. For years Wurdemannia has been considered a genus of uncertain taxonomic position (e.g., Silva et al., 

1996a; Abbott, 1999), or it was placed in the Gelidiaceae (e.g., 

Taylor, 1945; Dawson, 1953a) or the Wurdemanniaceae W. R. 

Taylor (1960). Saunders et al. (2004), noting their vegetative 

similarities, provided genetic evidence that Wurdemannia should 

be placed in the family Solieriaceae J. Agardh. 

The genus is represented by one species in the northern Gulf 

of California.

Wurdemannia miniata (Sprengel) J. Feldmann et G. Hamel

Sphaerococcus miniatus Sprengel, 1827:340.

Wurdemannia miniata (Sprengel) J. Feldmann et G. Hamel, 1934:544, figs. 

9–11; Dawson, 1944a:263; Taylor, 1945:151; Dawson, 1953a:86; 

1961b:410; Chávez-Barrear, 1972b:269; Huerta-Múzquiz and GarzaBarrientos, 1975:8; Huerta-Múzquiz and Mendoza-González, 1985:48; 

Salcedo-Martínez et al., 1988:83; Serviere-Zaragoza et al., 1993a:484; 

González-González et al., 1996:326, 409; CONANP, 2002:140; 

Serviere-Zaragoza et al., 2007:12; Bernecker, 2009:CD-Rom p. 63; 

Fernández-García et al., 2011:65. 

Fucus miniatus Draparnaud ex Lamarck et de Candolle, 1815:6, nom. illeg. 

[a later homonym of Fucus miniatus O. F. Müller, 1778:7].

Wurdemannia setacea Harvey, 1853:245.

Algae erect, short tufts or forming densely matted turfs; 1.5–

3.0 cm tall, of terete to slightly compressed, wiry axes, 150–220 

μm in diameter; arising from entangled, prostrate axes attached 

by small discs. Medulla of thick-walled, elongated cells; cells of 

medullary core mostly 7–8 μm in diameter, 50–800 μm in length 

(7–10 times longer than diameter); grading outward to cortex of 

smaller, thin-walled, ellipsoidal cortical cells, 3–5 μm in diameter; rhizines (hyphae, rhizoidal filaments).

Tetrasporangia zonately divided. Gametangial thalli not known.

Habitat. On rocks and sand, pebbles, or shells, 

sometimes entangled with other turf algae; mostly in lagoons 

and protected shallow bays; intertidal to shallow subtidal, down 

to about 0.5 m depths.

Distribution. Gulf of California: Bahía San Carlos; Puerto Escondido to Bahía La Paz; Nayarit to Jalisco. Eastern Pacific: Bahía Braithwaite, Isla Socorro (Islas Revillagigedo); 

Colima to Guerrero; El Salvador; Nicaragua; Costa Rica; Panama. Central Pacific: Hawaiian Islands. Western Pacific: China; 

Japan; Vietnam.

Type Locality. Vicinity of Montpellier, Mediterranean coast, France (Lipkin and Silva, 2002).

Remarks. Wurdemannia miniata is a widely reported species (Guiry and Guiry, 2009). In the field it can 

sometimes be confused with some of the small, terete species 

of the Gelidiales. Anatomically, W. miniata lacks rhizoidal filaments (hyphae, rhizines) in the medulla and cortex (seen in 

transections and longitudinal sections) of the Gelidiaceae and 

Pterocladiaceae, and has zonately divided tetrasporangia. The 

Gelidiellaceae also lack rhizoidal filaments, but along with the 

other Gelidiales they have tetrahedrally to decussately divided 

tetrasporangia.

Weeksiaceae

Weeksiaceae I. A. Abbott, 1968:181.

Algae are blade-like, and growth is uniaxial or, in some, 

initially uniaxial and becoming multiaxial. Auxiliary cells are 

separate from the carpogonial branch. There are usually several 

auxiliary cell branches on each supporting cell, some of which 

may be functional. Carpogonial branches have extremely large 

nutritive cells. Following fertilization of the carpogonium, one 
364 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

of the nutritive cells produces the gonimoblast. All cells of the 

maturing gonimoblast develop into carposporangia.

Remarks. Although the families Weeksiaceae and 

Dumontiaceae Bory de Saint-Vincent (1828) are sometimes considered to be a single family (e.g., Lindstrom and Scagel, 1987; 

see also Lobban and Wynne, 1981), others treat them as distinct 

(e.g., Abbott and Hollenberg, 1976; De Clerck et al., 2002).

There is one genus of the Weeksiaceae in the northern Gulf 

of California.

Weeksia Setchell

Weeksia Setchell, 1901:128.

Algae are entire, dissected, or lobed blades, with smooth 

to puckered surfaces. Growth is initially uniaxial, then becomes multiaxial. Medulla is composed of elongated, periclinal 

medullary filaments, with occasional anticlinal (rhizoidal) filaments from the cortical cells, and giant cells of primary axial 

filaments in longitudinal rows. These rows contribute to the veinlike thickenings basally. Cortex is of 3–5(–7) layers of subspherical cells; some of the larger inner cortical cells are connected to 

medullary filaments. Ultrastructurally, pit plugs are without cap 

layers (Pueschel and Cole, 1982:709, fig. 18).

Tetrasporangia are small, regularly to irregularly cruciately 

divided. Carpogonial branches and auxiliary cell branches have 

8–15 cells. Carpogonial branches bear four to five larger, conspicuous nutritive cells. After fertilization, the gonimoblast is produced 

from a nutritive cell. Carposporangia are developed from all of the 

gonimoblast cells. Carpospores are released through a carpostome 

of the cystocarp. Spermatangia are in patches on blade surfaces 

and cut off by an oblique wall from the spermatangial parent cells.

There are two species in the northern Gulf of California.

KEY TO THE SPECIES OF WEEKSIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Blades membranous, narrow to broadly lanceolate, up to 25 cm tall and to 10 cm wide; 200–500 μm thick . . . . W. coccinea

1b. Blades flaccid, slippery, orbicular to reniform, up to 15 cm tall, usually broader than tall; mostly 200–250 μm (rarely to 

400 μm) thick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . W. templetonii

Weeksia coccinea (Harvey) Lindstrom

FIGURE 181A,B

Schizymenia? coccinea Harvey, 1862:174 [with a generic query].

Weeksia coccinea (Harvey) Lindstrom, 1986:531, figs. 1, 2 (lectotype); 

Lindstrom and Scagel, 1987:2228 [in part], figs. 94–97, 99; Scagel et 

al., 1989:263 [in part]; Saunders, 2008:784, figs. 34–37; HernándezKantún et al., 2009:249, tbl. 1.

Halymenia coccinea (Harvey) I. A. Abbott, 1967a:141, figs. 1–3; Abbott 

and Hollenberg, 1976:425, fig. 379; Pueschel and Cole, 1982:709, fig. 

18; Norris, 1985d:210, fig. 16.4; González-González et al., 1996:222; 

Pacheco-Ruíz and Zertuche-González, 2002:467, tbl. 1. 

Weeksia fryeana Setchell, 1912:254; Dawson, 1961b:411; Norris and Abbott, 1972:90; Pueschel and Cole, 1982:709.

Aeodes gardneri sensu Smith, 1944:242, pl. 54, figs. 4, 5; Abbott, 1967a:140 

[non Aeodes gardneri Kylin, 1925:17, which is now Halymenia gardneri (Kylin) Parkinson, 1980:12].

Halymenia actinophysa sensu Dawson, 1954c:274 [in part; see Abbott, 

1967a:144; non Halymenia actinophysa M. Howe, 1911:509].

Blades usually singular, membranous, narrow to broadly 

lanceolate, up to 25 cm tall, to 10 cm wide, thin, 200–300 μm 

thick; bright cherry red in color; with simple or slightly undulate 

margins; base of blade usually cuneate above a short, sometimes 

divided stipe (if divided, each with a single blade) (Figure 181A); 

attached below by a small discoid holdfast. Medulla filamentous 

(Figure 181B); sparsely traversed by a few periclinal, anticlinal, 

and irregularly directed filaments, up to about 75 μm long, 5–10 

μm in diameter, and thin rhizoidal filaments. Outer cortex of 

1(–2) layers of small, isodiametric, highly granular, pigmented 

cells. Inner cortex of larger cells, 25–40 μm in diameter, subtented by 2–3 cells that connect to outer medullary filaments.

Tetrasporangia cruciately divided, 30–40 μm long, 15–22 

μm wide; scattered in cortex over blade surface. Cystocarps 

hemispherical, 200–300 μm in diameter, surrounded by few 

sterile filaments; scattered over and barely projecting above 

blade surface; carposporangia mostly 10–16 μm in diameter. 

Spermatangia not known in the northern Gulf (spermatangia 

reported from British Columbia: borne on outer layer of pigmented cortical cells; see Saunders, 2008: fig. 36).

 Habitat. Apparently rare, on rocks; subtidal, down 

to 10–25 m depths.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda; Islas de Los Gemelos, Bahía de Los 

Ángeles; Bahía de San Lucas. Eastern Pacific: southern Alaska to 

northern Washington (Saunders, 2008); Oregon to Baja California (Abbott and Hollenberg, 1976).

Type Locality. Griffin Bay (south of Friday Harbor), San Juan Island, San Juan County, Washington, USA.

Remarks. Using molecular analyses, Saunders 

(2008) elucidated the northeastern Pacific Weeksia coccinea, a 

species with a complicated taxonomic history. Gulf specimens, 

tentatively referred to W. coccinea, are in general morphological agreement with those from Washington–British Columbia 

(Saunders, 2008). To confirm its identity, northern Gulf material 

needs to be critically molecularly compared with type locality 

W. coccinea.

Weeksia templetonii Setchell et N. L. Gardner

FIGURES 181C, 182

Weeksia templetonii Setchell et N. L. Gardner, 1937:76, pl. 10: fig. 28 [type 

specimen]; Dawson, 1953a:91, pl. 7: fig. 1; 1961a:91, pl. 7: fig.1; 
NUMBER 96 • 365

1961b:411; Abbott, 1968:190; Lindstrom, 1986:531, fig. 3; GonzálezGonzález et al., 1996:223.

Halymenia templetonii (Setchell et N. L. Gardner) I. A. Abbott, 1967a:143, 

fig. 7; Abbott and Hollenberg, 1976:430, fig. 382; González-González 

et al., 1996:223; Anaya-Reyna and Riosmena-Rodríguez, 1996:864, 

tbl. 1; CONANP, 2002:140; Pacheco-Ruíz and Zertuche-González, 

2002:467, tbl. 1; Pacheco-Ruíz et al., 2008:207.

Blade mucilaginous, flaccid, orbicular to reniform (usually 

broader than tall), up to 15 cm tall; attached by a small discoid 

holdfast. Blades mostly thin, 200–250(–400) μm thick; usually 

with faint, false veins radiating near base (i.e., no differentiation 

of tissue evident in transection); with entire, irregularly lobed 

or lacerate margins. Medulla a network of medullary filaments 

composed of relatively straight cells, 40–85 μm long, 5–7 μm in 

diameter. Cortex of 3–4 layers of small cells.

Tetrasporangia cruciately divided, 22–26 μm long, 18–22 

μm in diameter; scattered over blade. Carpogonial branch of 6–8 

cells. Cystocarps up to 150 μm in diameter, embedded and scattered over blade. Spermatangia unknown.

Habitat. Rare, on rocks; subtidal, down to 20–30 

m depths.

Distribution. Gulf of California: Isla Coronado 

(Isla Smith; off Bahía de Los Ángeles); Bahía de Loreto to Canal 

FIGURE 181. Species of Weeksia. A, B. Weeksia coccinea: A. Habit

(JN-6546, US Alg. Coll.-159943). B. Diagrammatic transection of 

Weeksia coccinea. C. Weeksia templetonii: Diagrammatic transection.

FIGURE 182. Weeksia templetonii: Habit of a female gametophyte 

(JN-4349, US Alg. Coll.-159945).
366 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

de San Lorenzo (off Isla Espíritu Santo); Cabo Pulmo; Punta Los 

Frailes. Eastern Pacific: Anacapa Island (California Channel Islands); Isla Cedros (off Baja California).

Type Locality. 38 meter depth (dredged); off Isla 

Cedros (Osorio-Tafall, 1948), Baja California, Pacific Mexico.

Remarks. Lindstrom (1986), investigating some species of Halymenia and Weeksia, concluded that W. templetonii

was correctly ascribed by Setchell and Gardner (1937) to the 

genus Weeksia.

Peyssonneliales*

Peyssonneliales Krayesky, Fredericq et J. N. Norris, in Krayesky, Norris, Gabrielson, Gabriel, and Fredericq, 2009:384; Wynne and Kraft, 

2010:296.

Algae are crustose, prostrate, and usually epilithic. Crusts 

may be noncalcified throughout, calcified throughout, or partially calcified (with hypobasal calcification between the attachment rhizoids). Calcium carbonate, if present, is in the 

mineral form aragonite (James et al., 1988). The lower surfaces 

of the crusts are partially to completely attached to the substratum, either directly (i.e., without rhizoids) or by unicellular 

or multicellular rhizoids. Prostrate growth is by radiating marginal rows of transversely dividing apical initials in the basal 

layer (multiaxial); these later divide vertically to form a single 

upper or lower perithallial cell. The first order of the perithallial cells gives rise to simple or branched filaments that together 

form a loose to compact upper-only cortex or upper and lower 

cortices. Cortical cells have numerous discoid or ribbon-like 

chloroplasts.

Tetrasporophytes and gametophytes are isomorphic. Tetrasporangia are cruciately divided and borne terminally or laterally 

in tetrasporic nematheciathat are with or without multicellular 

paraphyses. Gametophytes, where known, are either monoecious or dioecious. Both the carpogonial branches and auxiliary 

cell branches are of three to six cells borne lateral on the erect filaments within nemathecia. Connecting filaments attach to one or 

often more than one auxiliary cell and develop small to sprawling fusion cells that bear the gonimoblasts. In some members, the 

gonimoblast may also develop directly from the connecting filament. Most cells of the gonimoblast produce carposporangia in 

short simple chains or branched chains. Spermatangia are apical 

or intercalary and develop on sympodial or apical spermatangial 

filaments within nemathecia.

Remarks. The molecular systematic study of 

Krayesky et al. (2009) clarified the taxonomy of Peyssonnelia, 

established the new order Peyssonneliales, and at that time 

* Contributed by David M. Krayesky and James N. Norris. D. M. 

Krayesky: Department of Biology, Slippery Rock University, Slippery 

Rock, Pennsylvania 16057, USA.

recognized the family Peyssonneliaceae to contain only two 

genera, Peyssonnelia and Sonderopelta Womersley et Sinkora 

(1981). Members of Peyssonneliales are worldwide in distribution and are found growing on hard substratum from the intertidal to deep subtidal, down to depths of 288 m (Littler et al., 

1985, 1986; Vadas and Steneck, 1988).

Currently the Peyssonniales contains one family, with some 

of its members occurring in the northern Gulf of California.

Peyssonneliaceae

Peyssonneliaceae Denizot, 1968:86, 308.

Squamariaceae J. Agardh, 1851:ix, 485, nom. illeg.

Algae of this family are usually prostrate, crustose, and 

dorsiventrally organized; others can have free horizontal or partially erect portions. They are partially to strongly attached to 

the substratum. Anatomically, there is a distinct basal hypothallium of laterally adjoined filaments, which may be calcified extracellularly in some and noncalcified in others. The lower or 

ventral surface of the hypothallium is without or bears rhizoidal 

attachments, whereas the upper hypothallium gives rise to the 

perithallium of vertical rows of erect filaments. Cystoliths or cell 

inclusions occur in some species.

Reproduction is usually by tetrasporangia, which are irregularly and cruciately divided in superficial nemathecia with 

slender multicellular paraphyses. Gametophytes and tetrasporophytes are isomorphic. Sexual reproductive structures are also 

borne in nemathecia and may be monoecious or dioecious but 

are apparently rare in field collections. Where known, carpogonial branches and auxiliary cells are three- to six-celled, separated by paraphyses, and borne in either superficial (on or at the 

surface) or elevated nemathecia above the surface. Carpogonial 

branches originate laterally from an intercalary cell of a nemathecial filament after the nemathcium is fully developed. Carposporangia are in unbranched to branched linear series in between 

paraphyses. Spermatangia are in small clusters within nemathecia and are usually without paraphyses.

Remarks. Currently 12 to 14 genera are listed in

the Peyssonneliaceae (Guiry and Guiry, 2010–2011). Denizot 

(1968) apparently planned further studies of Mexican specimens along with other crustose groups of Pacific species. In 

the Gulf of California much remains to be done, and it is suspected that more taxa will be found. The finding of gametangial specimens and comparative studies of their morphologies, 

life histories, and DNA analyses are necessary to resolve their 

taxonomy.

Three genera, Peyssonnelia, Metapeyssonnelia, and Cruoriella, are known in the northern Gulf of California. Of these, 

Metapeyssonnelia is generally treated in this family, but molecular analyses have shown it probably belongs in Dumontiaceae complex (Krayesky et al., 2009) or possibly in the in 

Rhizophyllidaceae F. Schmitz, and the status of Cruoriella is 

problematic.
NUMBER 96 • 367

KEY TO THE GENERA OF PEYSSONNELIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Crusts mucilaginous and relatively soft in texture (not “hard” due to a lack of calcification); adjacent perithallial filaments nonadherent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Cruoriella

1b. Crusts noncalcified to calcified (comparatively “hard”); adjacent perithallial filaments adherent . . . . . . . . . . . . . . . . . 2

2a. Hypothallus (ventral view) of more or less parallel or flabellate rows of cells; perithallus (in vertical section) primarily of 

upwardly directed (upright) perithallial filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Peyssonnelia

2b. Hypothallus (ventral view) of rows of cells arranged in a flabellate pattern; perithallus (in vertical section) typically of 

upwardly directed perithallial filaments, which in some portions of thallus changes to both upwardly and downwardly 

directed filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Metapeyssonnelia

Cruoriella P. Crouan et H. Crouan

Cruoriella P. Crouan et H. Crouan, 1859:289.

Algae are thin, noncalcified crusts, usually small, up to 2 

cm wide; soft and mucilaginous with the filaments of cell rows 

relatively easily separated under pressure; and attached to the 

substratum by rhizoids. In transection, the basal portion or 

hypothallus is of one to two cell layers. The upper portion or 

perithallus is composed of erect, mostly branched filaments. 

Reproductive structures are developed in nemathecia. Tetrasporangia are cruciately divided and borne terminally on filaments. Carpospores are in chains, mostly terminal on filaments. 

Spermatangia are also borne in chains, either lateral or terminal 

on filaments. 

Remarks. Cruoriella is somewhat similar in habit, 

structure, and reproduction to some species of Peyssonnelia. 

Cruoriella is usually separated from Peyssonnelia on its characteristic arching to fan-shaped superficial rows of cells (especially 

when viewed from the bottom), soft and mucilaginous texture, 

and relative ease with which the rows of cells (filaments) separate 

under pressure. Some taxonomists (e.g., Kylin, 1956; Yoneshige, 

1984, 1985; Maggs, 1990; Womersley, 1994) do not consider 

these features alone important enough to recognize Cruoriella

as distinct from Peyssonnelia. Others (e.g., Denizot, 1968; Silva 

et al., 1996a; Ballantine et al., 2000; Guiry and Guiry, 2009) 

continue to recognize Cruoriella. 

The generic status of the type of Cruoriella P. Crouan et 

H. Crouan (1859) is problematic. Denizot (1968) gave Cruoriella armorica P. Crouan et H. Crouan as the type of Cruoriella, 

and others have continued to recognize C. armorica (e.g., Silva 

et al., 1996a; Ballantine et al., 2000). Some (e.g., Taylor, 1960; 

Kato et al., 2005, 2006; Peña and Bárbara, 2010) have considered Cruoriella armorica to be a Peyssonnelia, as P. armorica

(P. Crouan et H. Crouan) Weber-van Bosse (in Børgesen, 1916). 

If this is followed, then Cruoriella would be congeneric with 

Peyssonnelia, and the other species of Cruoriella would need to 

be reinvestigated to resolve their generic placement, with some 

species possibly needing a new type and generic name.

Denizot (1968) also considered the generitype of another crustose genus, Cruoriopsis L. Dufour (1864), i.e., Cruoriopsis crucialis

L. Dufour, to be conspecific with Cruoriella armorica P. Crouan et 

H. Crouan (1859), thus reducing them to a single genus as Cruoriella. Abbott and Hollenberg (1976), however, recognized Cruoriella and Cruoriopsis to be separate genera. Later, Irvine (1983), 

noting similarities in morphology and the lateral position of tetrasporangia in both Cruoriopsis crucialis L. Dufour and Plagiospora gracilis Kuckuck (1897; generitype of Plagiospora Kuckuck 

(Gloiosiphoniaceae F. Schmitz, 1892), suggested the two may be 

congeneric. Thus, studies are needed to further clarify the generic 

status of Cruoriella as well as Cruoriopsis and Plagiospora.

There are two species of Cruoriella in the northern Gulf of 

California.

KEY TO THE SPECIES OF CRUORIELLA IN THE NORTHERN GULF OF CALIFORNIA

1a. Crust (200–)400–600 μm thick; loosely attached by a few rhizoids; tetrasporangia in elevated nemathecia, sessile or on 

1-celled pedicel; spermatangia in slightly elevate nemathecia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. fissurata

1b. Crusts 80–150 μm thick; firmly attached by a few rhizoids and a dense gelatinous basal layer; tetrasporangia terminal on 

2- to 6-celled filament (not in nemathecia) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. mexicana

Cruoriella fissurata E. Y. Dawson

FIGURE 183

Cruoriella fissurata E. Y. Dawson, 1953a:109, pl. 7: fig. 6, pl. 24: fig.1 

[type specimen]; 1957c:18; 1960a:38; 1966b:59; Nozawa, 1969:19, 

figs. 1A–F, 2A–F; León-Álvarez and González-González, 1993:461; 

González-González et al., 1996:195; Yoshida, 1998:767; Verlaque et 

al., 2000:194, tbl. 1; Pacheco-Ruíz et al., 2008:208; Berneker, 2009:CD 

p. 62; Fernández-García et al., 2011:61.

Peyssonnelia mariti sensu Denizot, 1968:122 [in part; only Cruoriella fissurata; non Peyssonnelia mariti (Weber-van Bosse) Denizot, 1968:122; 

basionym: Cruoriella mariti Weber-van Bosse, 1921:288].

Crusts, rose red to bright red (upon drying becomes purple 

red), lightly calcified; up to 10 cm or more across; (200–)400–

600 μm thick; growing irregularly by small fan-shaped or lobed 

portions, usually not overlapping; loosely attached by a few 

short, unicellular rhizoids. Surface in fresh specimens smooth, 
368 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

without striations; margins wavy and more or less lobed, margins may be unattached; upon drying, crust shrinks; surface of 

minute mound-like elevations, which form radiating, anastomosing ridges. Hypothallus surface seen from ventral (lower) 

view; of cell rows converging, diverging, and anastomosing in 

fan-shaped arrangement. Cells of hypothallus in transection, 

(30–)35–50(–60) μm long, 15–20 μm in diameter; some cells 

dense with starch grains. Perithallus of forked (usually twice) 

filaments of ascending cell rows; upper cells, mostly shorter than 

broad, 4–5 μm tall, 12–13 μm wide.

Tetrasporangia cruciately divided, about 70–80 μm long, 

(30–)50–60 μm in diameter; in elevated nemathecia, 100–150 μm 

tall, about 650 μm wide; covering surface areas, in elongated 

patches up to 1.0–2.0 mm wide; tetrasporangia among slender 

clavate paraphyses, with apices about 9 μm in diameter (after 

Dawson, 1960a). Carposporangial thalli not found in the northern Gulf. Carpogonial nemathecia (as reported in southern Japan; 

Nozawa, 1969) 170–190 μm tall, mostly 800 μm wide; with a 

thin gelatinous roof. Carpogonial branch 3-celled, terminal on 

supporting cell; among slender, unbranched paraphyses. Gonimoblast cells cut off from secondary connecting filament near 

auxiliary cell; all 2–4 cells develop into globose carposporangia, 

25–35 μm in diameter. Spermatangia in small, slightly elevated 

nemathecia, up to 220 μm or more wide and about 35 μm deep; 

spermatia, 2.0–2.5 μm in diameter, developed by transverse and 

longitudinal divisions of short, thick spermatangial parent cells.

Habitat. On rocks, shells, coralline rubble, and 

worm tubes; intertidal to shallow subtidal.

Distribution. Gulf of California: Isla San Lorenzo (southwestern Islas de la Cintura) to Guaymas; Punta 

Aguja (about 3.2 km SW of Punta Concepción); Cabeza 

Ballena. Eastern Pacific: Guerrero; Costa Rica to Panama. 

Western Pacific: Japan.

Type Locality. On intertidal rocks; Cabeza Ballena, Baja California Sur, Gulf of California, Mexico.

Cruoriella mexicana (E. Y. Dawson) Denizot

FIGURE 184

Cruoriopsis mexicana E. Y. Dawson, 1953a:99, pl. 10: figs. 11–14; 1957c:18; 

1960a:38; 1961a:193, pl. 1: figs. 2–5; 1961b:426; 1966a:21; 1966b:62; 

Mateo-Cid and Mendoza-González, 1992:21; Serviere-Zaragoza et al., 

1993a:483; Mendoza-González et al., 1994:105; González-González et 

al., 1996:195; CONANP, 2002:140.

Cruoriella mexicana (E. Y. Dawson) Denizot, 1968:149, fig. 134; LeónÁlvarez and González-González, 1993:461; González-González et al., 

1996:195, 388; L. Aguilar-Rosas et al., 2000:130; Bernecker, 2009:CDRom p. 62; Fernández-García et al., 2011:61.

Crusts small, thin, 80–150(–200) μm thick; attached beneath the basal cell layer by a hyaline gelatinous film and short 

descending rhizoids. Hypothallus of 1 layer; cells of filaments 

wider than tall, 8–12 μm tall by12–24 μm wide. Vertical filaments of perithallium arise from basal layer; irregularly and 

frequently branched; terete in tetrasporangial thalli and slightly 

clavate in carpogonial thalli. Cells of lower perithallium filaments more or less isodiametrical, 9–15 μm diameter; upper cells 

smaller, narrower, and elongated.

Tetrasporangia cruciately divided; long and slender, 70–80 μm 

long by 16–20 μm in diameter, borne terminally on 2- to 6-celled 

filaments among paraphyses. Carpospores ovate, 18–20 μm long; 

borne in short-branched chains, usually of 4 carpospores. Spermatangia reported by Dawson (1960a) but not described.

Habitat. On mollusks shells and rock; low intertidal 

to shallow subtidal.

FIGURE 184. Cruoriella mexicana: A. Vertical section through the 

type specimen, a sporophytic crust; tetrasporangia terminal on filaments among paraphyses (holotype). B. Vertical section through a 

nonreproductive portion (A, B, after Dawson, 1953a, pl. 10: figs. 11, 

12, as Cruoriopsis mexicana).

FIGURE 183. Cruoriella fissurata: Habit of the crust on rock (type 

specimen: EYD-6830a, AHFH, now UC).
NUMBER 96 • 369

Distribution. Gulf of California: Playa Las Conchas (Playa Estación), Puerto Peñasco; San Felipe; Bahía de Loreto; Laguna Agiabampo; Mazatlán, Sinaloa to Jalisco. Eastern 

Pacific: Islas Los Coronados (off northwest Baja California); Colima to Guerrero; Costa Rica.

Type Locality. On shells, dredged 13–15 m depths; 

off Isla Coronado Sur (South Island; 32°24.5′N, 117°13.8′W), 

Islas Los Coronados, Baja California, Pacific Mexico.

Remarks. Cruoriella mexicana is not well known in 

the northern Gulf of California. Originally described in the genus 

Cruoriopsis (Dawson, 1953a), it was subsequently transferred to 

Cruoriella by Denizot (1968). Although similar to Peyssonnelia 

japonica (Segawa) Yoneshigue (1984; basionym: Cruoriopsis japonica Segawa, 1941; =Cruoriella japonica (Segawa) Denizot, 

1968), the Pacific Mexico and Gulf of California Cruoriella 

mexicana grow on shells and rocks, have a single basal layer of 

nontrapezoidal cells, and comparatively taller, slightly narrower 

tetraspores (70–80 μm tall; 16–20 μm in diameter). In contrast, 

Peyssonnelia japonica of the northern Gulf are epiphytic, have 

a basal layer of 1–2 trapezoidal cells, and smaller tetraspores 

(mostly 45–50 μm tall and 16–30 μm in diameter) (R. AguilarRosas et al., 2007a). More specimens of northern Gulf Cruoriella mexicana are needed to evaluate its taxonomic status and 

phylogenetic relationship to type locality specimens and those 

of the northern Gulf referred to P. japonica. See also Remarks 

under Peyssonnelia japonica.

Metapeyssonnelia Boudouresque, 

Coppejans et Marcot

Metapeyssonnelia Boudouresque, Coppejans et Marcot, 1976:288.

Crusts are orbicular, spreading, and usually dark red or 

dark purple-red to blackish in surface view. Calcification is light 

to heavy, varying from complete (e.g., the type species (M. feldmannii Boudouresque, Coppejans et Marcot) to only partial and 

hypobasal in others. Most are attached by unicellular rhizoids 

cut off from central or distal ends of hypothallial cells, but at 

least one is attached by multicellular rhizoids (i.e., the Pacific 

Mexcio M. mexicana). Hypothallial cells are arranged in a flabellate or parallel pattern (in ventral view) and produce a single 

row of coxal (proximal perithallial) cells that nearly cover the 

bearing hypothallial cells or are cut off from the distal end of 

the hypothallial cells (seen in section views). Perithallial cells (as 

seen in sections) are cut off from coxal cells and regularly grow 

upward (mostly at angles of 45°–90°) to form the perithallus, 

but in some portions they can also differentiate into a superior 

(upper) perithallus of upward filaments and also an inferior 

(lower) perithallus of downward filaments. Basal hair cells are 

present in the upper perithallus of some species. Cystoliths may 

be present in the lower thallus of some species.

Tetrasporangial nemathecia may be superficial or sunken. 

Tetrasporangia are borne on a basal nemathecial cell (as in 

M. corallipeda Verlaque, Ballesteros et Antonius, 2000) or on 

cup-shaped cells cut off from basal nemathecial cell (Ballantine 

et al., 2014). Carposporangial nemathecia (where known) are 

superficial and contain elongated carposporangia in simple to 

occasionally branched chains of two to four cells (Ballantine et 

al., 2014). Spermatangia (where known) are in sori up to 50 μm 

high. Terminal perithallial cells cut off small squarish or triangular cells distally that produce clusters of elongate spermatangial 

parent cells. Spermatangia are cut off distally from spermantangial parent cells, initially in simple chains. Later, in most cases, 

they divide longitudinally, and each division subsequently divides 

transversely to form tetrads of spermatangia. Further irregular divisions result in disorganized groups of spermatangia (spermatangia after M. milleporoides D. L. Ballantine et H. Ruiz, 2011).

Remarks. Although Metapeyssonnelia is superficially very similar to Peyssonnelia, these genera can be distinguished by characters only seen in anatomical sections. 

Hypothallial cells of Metapeyssonnelia develop a single row of 

coxal cells that can produce perithallial filaments directed both 

upward and downward to form a lower and upper perithallus 

(Verlaque et al., 2000; “fountain-like” structure of Boudouresque et al., 1976). In contrast, the hypothallus of Peyssonnelia 

develops only upward (upright) perthallial filaments to form the 

perithallus. Some species of Metapeyssonnelia have been found 

only on nonliving substrata (e.g., rocks, tidal platforms, shells, 

or dead coral fragments), whereas a few Caribbean species are 

known to overgrow and kill corals (Verlaque et al., 2000; Ballantine and Ruíz, 2011).

There are five known species of Metapeyssonnelia. One, M. 

mexicana, is the only member of the genus currently known in 

the Pacific. It and another, possibly a new species, are known in 

the northern Gulf of California (and are included in the Key to 

Peyssonnelia and Metapeyssonnelia herein under Peyssonnelia).

Metapeyssonnelia mexicana (E. Y. Dawson) D. L. Ballantine et 

H. Ruíz

FIGURE 185

Ethelia mexicana E. Y. Dawson, 1953a:100, pl. 11: figs. 7–8; 1966a:17; 

1966b:59; González-González et al., 1996:200 [non Peyssonnelia 

mexicana E. Y. Dawson, 1953a:106; non Cruoriopsis mexicana E. Y. 

Dawson, 1953a:99; =Cruoriella mexicana (E. Y. Dawson) Denizot, 

1968:149].

Metapeyssonnelia mexicana (E. Y. Dawson) D. L. Ballantine et H. Ruíz, 

2011:50, tbl. 1.

Peyssonnelia dawsonii Denizot, 1968:109, figs. 94, 95; León-Tejera et al., 

1993:200; León-Álvarez and González-González, 1993:462; Verlaque 

et al., 2000:194, tbl. 1.

Crusts dark purple–red, closely following contour of substratum, often covering 3 cm or more, 400–1000 μm thick; 

lightly calcified only in basal portion; firmly attached by multicellular rhizoids along margins at first; later, thallus tissue grows 

downward, penetrating and filling irregularities in the substratum. Hypothallus cells arranged parallel to irregularly. Upper 

perithallus of laterally adjoined, branched cells in vertical rows. 

Lower perithallus cells irregularly arranged in some portions and 

stratified in other portions. Cells of lower perithallus 4–8 times 
370 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

longer than wide, becoming smaller and shorter upward to surface cells, 4–6 μm in diameter.

Tetrasporangia elongated, 45–50 μm long by 18–20(–35) 

μm in diameter; within sunken sori, 1 mm (or more) wide, 120–

130 μm deep. Paraphyses within sori unbranched, of 7–8 slightly 

clavate cells, up to 3.5 μm wide. Other reproductive structures 

are unknown in northern Gulf specimens.

Habitat. On rocks, tidal platform, and into crevices; 

high to low intertidal.

Distribution. Gulf of California: Punta Peñasco 

and Playa Las Conchas (Playa Estación), Puerto Peñasco; 

Nayarit. Eastern Pacific: Guerrero.

Type Locality. Bahía de Acapulco, Guerrero, Pacific Mexico.

Remarks. Metapeyssonnelia mexicana is currently 

the only member of the genus known in the Pacific. It has been 

reported in the upper Gulf of California (Dawson, 1966a, 1966b, 

as “Ethelia mexicana”), considerably northward from its type 

locality in Guerrero, Pacific Mexico. Other specimens cited by 

Dawson (1966a:17) as “Peyssonnelia sp.,” also from the upper 

Gulf in Puerto Peñasco, were noted as “not specifically distinct 

from Ethelia” and thus should be reexamined.

Denizot (1968, as “Peyssonnelia dawsonii”) examined the 

type specimen of Ethelia mexicana E. Y. Dawson (1953a), observing perithallial cells in upper parts to be in vertical rows and 

irregular in some portions of the lower thallus, thus lacking a 

generic character of Ethelia Weber-van Bosse (1921)—i.e., the 

absence of distinct cell rows. The lightly calcified E. mexicana

has a hypothallus of parallel filaments and both ascending and 

descending rows of perithallial cells (Verlaque et al., 2000), characteristics recognized by Ballantine and Ruíz (2011) as occurring 

in Metapeyssonnelia.

Metapeyssonnelia sp. A

Crusts thin, 146–192 μm thick; hypobasal calcification 

light; attached by unicellular to multicellular rhizoids. Hypothallus cells 13.5 μm tall by 32 μm wide, in a single, more or less 

parallel row. Upper perithallus of laterally adherent cells in vertical rows; branched near apex; occasionally with a terminal basal 

hair cell. Cells of perithallus longer than wide; lower perithallus 

cells 18 μm long by 10.8 μm in diameter, curved upward from 

hypothallial cells; becoming smaller and shorter upward to surface cells, about 6.3 μm long by 4.5 μm in diameter. 

Reproduction not found.

Habitat. On rocks and tidal platform; intertidal.

Distribution. Gulf of California: Playa Las Conchas (Playa Estación), Puerto Peñasco.

Remarks. This upper Gulf specimen (US Alg. Coll.) 

is referred to Metapeyssonnelia sp. A and may be an undescribed 

species. More collections for further morphological and molecular analyses will help clarify its taxonomic status. If found to be a 

Metapeyssonnelia, it would be the second known Pacific species.

Peyssonnelia Decaisne

Peyssonnelia Decaisne, 1841:168, 196–197, pl. 5: figs. 16, 17, 28; Decaisne, 

1842a:360; Descaine, 1842b:126; Krayesky et al., 2009:374, figs. 1, 2.

Prostrate crusts that are usually more or less circular or 

lobed in surface view. Some species are noncalcified, whereas 

others contain hypobasal calcification. Crusts may be tightly adherent to loosely attached to the substratum by unicellular or 

multicellular, simple or branched rhizoids; some crusts with distal portions of the thallus free (unattached). Crusts are usually 

of 2 distinct layers: a hypothallus composed of filaments 1 layer 

thick and a perithallus of multilayers of filaments in vertical rows 

FIGURE 185. Metapeyssonnelia mexicana: A, B. Vertical sections, showing some unicellular rhizoids, and the perithallus of more or 

less assurgent filaments that become slightly more vertical near crust surface (GJH-67-54, US Alg. Coll. microscope slide 3109).
NUMBER 96 • 371

of cells; however, there are also some with a subhypothallic layer. 

Dorsal surface is formed by cortical cells of the perithallus, and 

ventral surfaces by cells of the hypothallus. Cells in some species 

are reported to have cystoliths or crystals as cell inclusions. Portions of the surface layer of cells develop filaments of sterile cells 

among which the reproductive structures are developed.

Reproductive structures develop within elevated nemathecia, scattered over the perithallus. Tetrasporangia are cruciately 

divided and usually terminal on filaments that are interspersed 

with paraphyses. Gametophytes, where known, are monoecious or dioecious, and also develop intermixed with paraphyses within nemathecia. Carpogonial branches are 3- to 6-celled. 

Auxiliary cells are intercalary in auxiliary cell branches of 3–6 

cells. Gonimoblasts develop from the place of fusion of a segment of the connecting filament to the diploidized auxiliary cell 

and, as they mature, produce only a few large carposporangia. 

Spermatangia are borne terminally on erect spermatangial filaments, abundantly grouped in nemathecia without paraphyses.

Remarks. In reviewing the genus Peyssonnelia, 

Maggs and Irvine (1983) elucidated reproductive characters 

that were not known for many of the species. More recently, 

Krayesky et al. (2009) clarified the genus on the basis of morphological studies and molecular analysis of Peyssonnelia.

There are four species reported in the southern Gulf (Dawson, 1953a, 1961b, 1966b): Peyssonnelia squamaria (S. G. 

Gmelin) Decaisne (1842a; basionym: Fucus squamarius S. G. 

Gmelin, 1768) from Isla San Ildefonso and Islas Santa Inez 

(Dawson, 1966b) and San José del Cabo, P. conchicola Piccone 

et Grunow (in Piccone, 1884) from Bahía Concepción and Cabo 

San Lucas (Dawson, 1953a, 1957a), P. hancockii (E. Y. Dawson) 

Denizot (1968; basionym: Cruoriella hancockii E. Y. Dawson, 

1953a) from Cabeza Ballena, and P. pacifica Kylin (1925) from 

Mazatlán. Further collections and critical studies should reveal 

additional species in the Gulf of California.

Currently, three species of Peyssonnelia are known in the 

northern Gulf of California.

KEY TO THE SPECIES OF PEYSSONNELIA AND METAPEYSSONNELIA 

IN THE NORTHERN GULF OF CALIFORNIA

1a. Crust composed of erect vertical rows of cells throughout; loosely attached to substrate by unicellular rhizoids . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Peyssonnelia orientalis

1b. Crusts partly of vertical cell rows and ascending and descending cell rows or entirely of ascending cell rows; firmly attached to substratum by multicellular or unicellular rhizoids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Crusts with upper thallus of curving to vertical rows of cells from distinctive hypothallus, or with ascending and desending rows of cells; attached by multicellular rhizoids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2b. Crusts composed entirely of ascending cell rows; attached by short unicellular rhizoids . . . . . . . . . . . . . . . . . . . . . . . . 4 

3a. Crust upper thallus composed of only vertical rows of cells; lower portion of ascending and descending rows of cells; firmly 

attached to substrate by multicellular rhizoids and by downward-growing tissue . . . . . . . . . . Metapeyssonnelia mexicana

3b. Crust with perthallus of curving rows of cells rising upward from a single row of hypothallial cells . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Metapeyssonnelia species A

 4a. Crust basal layer of trapezoidal cells; attached by unicellular rhizoids from basal cells; tetrasporangia mostly 45–50 μm 

tall and 16–25(–30) μm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Peyssonnelia japonica

4b. Crust basal layer of nontrapzoidal cells; firmly attached by short unicellular rhizoids; tetrasporangia longer and wider, 

60–100 μm long, 22–35 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Peyssonnelia mexicana

Peyssonnelia japonica (Segawa) Yoneshigue

Cruoriopsis japonica Segawa, 1941:259, fig. 7A–F; 1977:68, pl. 39: fig. 305.

Peyssonnelia japonica (Segawa) Yoneshigue, 1984:134; Yoshida, 1998:770; 

Kato et al., 2006:931; R. Aguilar-Rosas et al., 2007a:154, figs. 3A–D; 

Y.-P. Lee, 2008:363, figs. A–C. 

Cruoriella japonica (Segawa) Denizot, 1968:147, 309, fig. 133; Sohn and 

Kang, 1980:74, pl. II: figs. 5–10.

Crusts mostly 170–180(–220) μm thick; attached by unicellular rhizoids, occasionally issued from basal cells. Hypothallus 

in cross section of 1–2 layers of basal cells, 2–3 times broader 

than tall, 8–16 μm tall, (10–)14–20 μm broad (long); trapezoidal cells above horizontal basal cells upward forms a perthallus 

of vertical rows of 10–16 smaller, squarish to slightly elongated 

cells, (4–)8–12 μm tall and mostly (4–)6–8 μm in diameter.

Tetrasporangia cruciately divided, 45–50(–90) μm tall and 

16–25(–30) μm in diameter; borne on stalk of 1–5 cells, lateral 

on vertical filament. Sexual reproduction not described. 

Habitat. Epiphytic on Ceratodictyon variabile in 

tide pools; intertidal. 

Distribution. Gulf of California: Playa Las Conchas 

(Playa Estación), Puerto Peñasco. Western Pacific: Japan; Korea. 

Type Locality. Crusts on mollusk shell (Tegula 

rustica); Sirahama, Miyake-zima, Izu Islands, Japan.

Remarks. A western Pacific species, Peyssonnelia 

japonica was described on a mollusk shell from one of the Izu 

Islands south of Tokyo. It has since been reported in the eastern 

Pacific from upper Gulf of California as an epiphyte on Gelidiopsis (R. Aguilar-Rosas et al., 2007a). As we have not seen their 

specimens, the description is based on Segawa (1941) and in part 

on R. Aguilar-Rosas et al. (2007a). Comparative molecular testing of the northern Gulf P. japonica with those from the type 

locality will elucidate their relationship. Kato et al. (2006) provided molecular support that the species belongs in Peyssonnelia 

and that it was distinct from P. armorica (P. et H. Crouan) Weber 
372 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

van-Bosse (in Børgesen, 1916; generitype of Cruoriella). See also 

Remarks under genus Cruoriella and C. mexicana. 

Peyssonnelia mexicana E. Y. Dawson

FIGURE 186

Peyssonnelia mexicana E. Y. Dawson, 1953a:106, pl. 11: figs. 1, 2; 1961b:412; 

Dreckmann et al., 1990:30; Dreckmann, 1991:33; León-Tejera et al., 

1993:200; León-Álvarez and González-González, 1993:462; GonzálezGonzález et al., 1996:247.

Crusts expanding up to 3 cm or more in width; surface 

relatively smooth (any irregularities reflect those of substratum), 250–550(–600) μm thick; firmly adherent to substratum 

by short unicellular rhizoids. Hypothallus distinct, of parallel cell rows; cells 8–15 μm tall, 25–30 μm wide, 25–30 μm 

high in lower surface view, with basal cuticle up to 10 μm 

thick. Perithallus of ascending cells, upward forming vertical 

rows, 1–2 times branched, usually in second to fifth tier; cells 

rectangular, about twice as long as wide, becoming smaller 

FIGURE 186. Peyssonnelia mexicana: A. Habit, surface view of crust (EYD-12137, US Alg. Coll.-12357). B. Vertical section showing 

thick perithallus and spermatangial nemathecia with extensive closely adjacent vertical rows of spermatangia (EYD-26098, US Alg. 

Coll. microscope slide 800). C. Section through an empty tetrasporangial nemathecia (tetrasporangia already discharged) showing 

slender, unbranched paraphyses arising from upper surface of crust. D. Small portion of section through elevated tetrasporangial nemathecia showing cruciately divided sporangia among unbranched paraphyses (C, D, EYD-26099, US Alg. Coll. microscope slide 799).
NUMBER 96 • 373

in size upward to surface layer; uppermost cells 6–8 μm in 

diameter.

Tetrasporangial nemathecia elevated, about 130–150 μm 

tall; tetraspores 60–100 μm long, 22–35 μm in diameter; among 

usually dense, unbranched paraphyses, of up to 7 elongate cells, 

from 2 to 4 μm in diameter at base, upper 2–3 cells shorter and 

5 μm in diameter at apices; apical cell sometimes more or less 

pointed. Carpogonial not known. Spermatangia in vertical rows 

within elevated nemathecia.

Habitat. On rocks; intertidal.

Distribution. Gulf of California: Isla Las Ánimas (Isla 

San Lorenzo Norte), Islas de San Lorenzo (southwestern Islas de la 

Cintura). Eastern Pacific: Cabo Colnett, Baja California to Oaxaca.

Type Locality. Granite rock outcrop; southeast 

side of Bahía Acapulco, Guerrero, Pacific Mexico.

Peyssonnelia orientalis (Weber-van Bosse) Cormaci et 

G. Furnari

FIGURE 187

Peyssonnelia rubra f. orientalis Weber-van Bosse, 1921:272, fig. 89.

Peyssonnelia orientalis (Weber-van Bosse) Cormaci et G. Furnari, 

1987:757; Yoshida, 1998:771; Mendoza-González and MateoCid, 1999:43, figs. 7–9; L. Aguilar-Rosas et al., 2000:130; MateoCid et al., 2006:55; Serviere-Zaragoza et al., 2007:11; Y.-P. Lee, 

2008:364, figs. A–C.

Peyssonnelia rubra var. orientalis Weber-van Bosse in Dawson, 1953a:104, 

pl. 10: figs. 8, 9; 1957a:3; 1959a:20; Dawson et al., 1960a:72, pl. 17: 

fig. 3; Dawson, 1961b:412; Denizot, 1968:122; Nozawa, 1972:45, fig. 

2A–H; Abbott and Hollenberg, 1976:371, fig. 310; Huerta-Múzquiz, 

1978:338; Stewart and Stewart, 1984:143; Mendoza-González and 

Mateo-Cid, 1986:422; Stewart, 1991:77; Mateo-Cid and MendozaGonzález, 1992:21; Mendoza-González and Mateo-Cid, 1992:17; 

León-Álvarez and González-González, 1993:462; Serviere-Zaragoza et 

al., 1993a:484; Mateo-Cid et al., 1993:47; Mateo-Cid and MendozaGonzález, 1994b:39; Mendoza-González et al., 1994:105; GonzálezGonzález et al., 1996:247; Mateo-Cid et al., 2000:64; CONANP, 

2002:140; Riosmena-Rodríguez et al., 2005a:34.

Peyssonnelia orientalis (Weber-van Bosse) Boudouresque et Denizot, 

1975:42, comb. inval.

Peyssonnelia rubra sensu Setchell et N. L. Gardner, 1930:175; Taylor, 

1945:168; Huerta-Múzquiz and Garza-Barrientos, 1975:8 [non Peyssonnelia rubra (Greville) J. Agardh, 1851:502].

Crusts, spreading up to 8 cm wide, deep rose red to crimson, close to substratum but loosely attached by unicellular 

rhizoids; margins sometimes unattached. Crust lightly calcified 

only in basal portion, 100–300 μm thick; surface view showing longitudinal striations and sometimes faint concentric bands; 

margins simple or occasionally lobed. Hypothallus of cells taller 

than broad in transection, 25–40 μm long by 12–16 μm wide, 

with rounded walls, giving them the appearance of cobblestones. 

Perithallus of unbranched, vertical rows of cells, usually 6–10 in 

number; lower cells more or less isodiametric or taller than wide; 

upper cells flattened, 11–16 μm wide.

Tetrasporangial nemathecia elevated, 80–160 μm tall; tetrasporangia ovate to elongate, 70–110 μm long, 25–55 μm wide, 

in a gelatinous matrix with unbranched or single branched, 

slightly clavate, paraphyses. Sexual reproduction unknown in 

Gulf material.

Habitat. On rocks and shells; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco to 

Isla San Jorge; San Felipe to Bahía Agua Verde; Isla Cholla (NNW 

of Isla Carmén) to Punta Palmilla; Mazatlán, Sinaloa to Jalisco. 

Eastern Pacific: California Channel Islands to Isla Guadalupe and 

Isla Cedros (Baja California); Isla Clarión, Isla Socorro and Isla San 

Benedicto (Islas Revillagigedo); Bahía de Ballenas to Playa Los Cerritos (south of Todos Santos), Baja California Sur; Jalisco to Colima; 

Oaxaca; Galápagos Islands. Western Pacific: China; Korea; Japan.

FIGURE 187. Peyssonnelia orientalis: A. Radial vertical section 

through nonreproductive crust showing the basal, single-layered 

hypothallus with numerous unicellular rhizoids, and erect vertical 

filaments forming the multilayered perithallus (6–10 cell rows high). 

B. Tangential section (A, B, JN-5214, US Alg. Coll. microscope slide 

4564). C. Part of a radial vertical section through nemathecia showing cruciately divided tetrasporangia among single-branched paraphyses arising from the upper surface of the crust (after Dawson, 

1953a: pl. 10: fig. 9, as P. rubra var. orientalis).
374 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Type Locality. Not specifically designated; various syntype localities are in the Philippine Islands and Indonesia 

(Silva et al., 1996a:213).

Remarks. Gulf of California Peyssonnelia orientalis are lightly calcified and relatively thin, with vertical rows of 

perithallial cells and elevated, more or less gelatinous tetrasporangial sori, and attached loosely by unicellular rhizoids (most 

notably at margins), in agreement with the Pacific concept of the 

species (Weber-van Bosse, 1921; Dawson, 1953a, as “P. rubra

var. orientalis”). Peyssonnelia orientalis was reported to be in 

the shaded intertidal to about 20 m depths throughout Pacific 

Mexico (Dawson et al., 1960a). Although Denizot (1968) commented that Dawson’s (1953a) material was similar to small 

specimens of the Atlantic P. inamoena Pilger (1911), the Gulf of 

California P. orientalis is different (for species comparisons, see 

Schneider and Reading, 1987; Womersley, 1994).

Gracilariales*

Gracilariales Fredericq et Hommersand, 1989a:225; Hommersand and Fredericq, 1990:138.

Algae of this order are mostly erect and free-living, with 

one to several cylindrical, compressed or flattened, branching or 

divided thalli that arise from small to large, discoid to crustose 

holdfasts. Cylindrical members are often wiry or stringy and 

mostly branched or occasionally unbranched. Other species are 

slightly compressed, slender, or strap-like, and some are distinctly 

flattened, narrow to broad, and branching to foliose. Although 

their anatomy appears to be multiaxial with a pseudoparenchymatous medulla, detailed examination of the uppermost apical 

regions reveals uniaxial growth, which becomes quickly obscure 

below. The cortex is composed of a few to many layers of small, 

pigmented cells that surround a medulla of larger hyaline cells. 

The outer cortical layer may have enlarged, hyaline, hair-like 

cells. A few members are parasitic genera that are minute, whitish, subglobose to irregularly globose thalli found growing on 

some of the larger pigmented members of the order.

Tetrasporophytes and gametophytes are isomorphic. Tetrasporangia develop on cortical cells, become cruciately divided, 

and may be scattered throughout or in sori on the cortex or 

borne in specialized branches. Carpogonial branches are twocelled, borne laterally on cortical cells, with a supporting cell 

that produces two to three sterile filaments, each two cells long. 

After fertilization, the carpogonium fuses with its supporting 

cell to form a large fusion cell, and sterile filament cells fuse and 

transfer their contents into the fusion cell. There are no auxiliary 

cells. The gonimoblasts develop outward from the fusion cell, 

usually in rows, with the outer cells developing carposporangia. 

Cystocarps project from the thallus surface or along its margins. 

* Contributed by James N. Norris and C. Frederico D. Gurgel. C. F. D. 

Gurgel: University of Adelaide, School of Earth and Environmental 

Sciences, Adelaide, South Australia 5005, Australia.

The carposporophyte is within a multilayered pericarp, with 

an ostiole. Traversing filaments connect to the pericarp in some 

members and are lacking in others. Spermatangia are formed 

superficially in sori or within shallow cavities to deep pits within 

the cortical cells.

Remarks. The Gracilariales contains two families 

(Fredericq and Hommersand, 1989a, 1990; Hommersand and 

Fredericq, 1990; Gurgel and Fredericq, 2004), the large, wellestablished Gracilariaceae and the smaller Pterocladiophilaceae

K.-C. Fan et Papenfuss (1959).

The Gracilariaceae exhibits a high diversity of species in the 

Gulf of California.

Gracilariaceae

Gracilariaceae Nägeli, 1847:240, 254.

Most members of the family are erect and free-living and 

cylindrical, compressed, or flattened (in the Gulf of California, 

Gracilaria and Gracilariopsis). These species are of variable size 

and shape, more or less freely branched or divided, and range 

from cylindrical and stringy to sometimes slightly compressed 

or flattened strap-like forms and often broad, blade-like forms. 

The other genus in the Gulf, Gracilariophila, is a minute, whitish 

parasite on Gracilaria.

Growth is uniaxial and apical. In structure, all members of 

the family are pseudoparenchymatous, with a medulla of large, 

more or less isodiametric cells and a cortex of successively 

smaller cells to the outer cortical surface of pigmented cells. 

Tetrasporangia are cruciately divided. The female reproductive 

apparatus is a two-celled carpogonial filament on a supporting cell that bears sterile filaments. After fertilization, a large 

number of adjoining cells fuse with the fertile cells and produce 

a large fusion cell at the base of the gonimoblast cells. The 

gonimoblast filaments grow toward the thallus surface, with all 

but the center cells developing into carposporangia. Cystocarps 

are surrounded by a thick pericarp with an ostiole, protruding 

above the thallus surface. Internally, the cystocarp is with or 

without nutritive filaments connecting the gonimoblast cells to 

the pericarp. Spermatangia develop in different ways depending on the species: continuous or in patches over the thallus 

surface, within slightly sunken to shallow sori or patches, or 

developed within the cortical cell layers in shallow to deep pits 

or cavities.

Remarks. A large family of 13 genera (Guiry and 

Guiry, 2008–2010), the Gracilariaceae includes many members 

that are economically important, used as foods and collected and 

grown for the personal, commercial, or industrial use of their 

phycocolloids, agar, and agarose (Chen et al., 2009). When only 

nonreproductive thalli are found, the species can be difficult to 

impossible to accurately indentify on the basis of vegetative anatomical characters alone.

The Gracilariaceae is well represented in the Gulf of California by two of its free-living, macrophytic genera and one minute, 

parasitic genus.
NUMBER 96 • 375

KEY TO THE GENERA OF GRACILARIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Minute, whitish, globose parasites, less than 4 mm in diameter; growing on Gracilaria. . . . . . . . . . . . Gracilariophila

1b. Free-living (nonparasitic) macrophytes, cylindrical to flat; over 2 cm and usually much taller or longer when mature 

(some cylindrical species up to 1 m or more in length) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Cystocarps with traversing filaments (absorbing filaments) in pericarp floor and surrounding walls; spermatangia in pits 

or conceptacles within cortex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gracilaria

2b. Cystocarps without traversing filaments (absorbing filaments) in pericarp; spermatangia superficial, produced from outer 

cortical cells . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gracilariopsis

Gracilaria Greville

Gracilaria Greville, 1830:iiv, 121; Fredericq and Hommersand, 1989a:213–

217; Steentoft et al., 1991:663.

Algae are exceedingly variable in size; most are erect, but 

a few are low growing or prostrate. Thalli of most of the species are composed of one or more cylindrical, compressed, or flat 

fronds attached to the substrate by a discoid holdfast or prostrate 

branches; a few species have irregularly constricted to articulated 

fronds of cylindrical or irregularly shaped segments. Branching 

in most is pseudodichotomous or irregular, and some may have 

proliferous branchlets. Uniaxial growth is not easily seen because 

of the compact nature of the apical structure. The medulla is 

pseudoparenchymatous, composed of large colorless cells, with 

an abrupt or gradual transition to a cortex of successively smaller 

cells toward the outer cortex of pigmented cortical cells.

Tetrasporangia are cruciately divided, embedded in the cortex 

or in modified cortical cells and scattered over the thallus. Cystocarps are hemispherical to ovoid, projecting and scattered over 

branches. Pericarp is ostiolate, with thick walls and traversing 

filaments (tubular nutritive cells sensu Sjöstedt, 1926; Fredericq 

and Hommersand, 1990; also referred to as absorbing filaments, 

connecting filaments, or nutritive filaments) that connect the 

gonimoblast to the pericarp (Yamamoto, 1978: fig. 29; e.g., Figure 

190A). Carposporangia are developed mostly in chains, but in most 

mature cystocarps this organization is not evident. Spermatangia 

are either covering the floor within shallow, cup-shaped depressions (Textorii-type; sensu Yamamoto, 1978: fig. 29; e.g., Figures 

190B, 191C, 193E) or lining the inner surfaces within horse-shoeshaped deep, ovoid to oblong pits or cavities (Verrucosa-type; 

sensu Yamamoto, 1978: fig. 29; e.g., Figure 196C).

Remarks. Species of Gracilaria are widely distributed but are often difficult to distinguish on habit characters 

alone. There is often a high degree of morphological plasticity, 

and species limits for many are poorly known. Complexes of 

similar-looking species can usually be separated by comparative morphological studies, elucidation of anatomical vegetative 

and reproductive characters, including the ontogeny of gametophytes, pre- and postfertilization events, and comparative molecular analyses (e.g., Gurgel and Fredericq, 2004; Gurgel et al., 

2003a, 2003b, 2004, 2008).

Fifteen species of Gracilaria and a species of uncertain taxonomic status are known in the northern Gulf of California. Two 

other species from the southern Gulf, G. ascidiicola and G. ramisecunda (Norris, 1985b), and two uncertain records are also 

included to call attention to the need for further study.

KEY TO THE SPECIES OF GRACILARIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thallus cylindrical throughout or cylindrical to only slightly compressed or becoming oval . . . . . . . . . . . . . . . . . . . . . 2

1b. Thallus distinctly complanate or flattened throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

2a. Thallus cylindrical, slender; axes less than 3 mm in diameter (one species up to 4–5 mm) . . . . . . . . . . . . . . . . . . . . . . 3

2b. Thallus rigid and erect, cylindrical, subcylindrical to more or less compressed or oval, mostly greater than 3 mm in diameter; variously branched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

3a. Thalli more rigid, smaller, mostly up to 15 cm tall, 1.0–1.3 mm in diameter; mostly branching from lower portions; arising from stoloniferous base . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. papenfussii

3b. Thalli usually over 25 cm in length; generally more robust, 2–4(–5) mm in diameter; branching mostly 3–5 orders; cystocarps with weakly developed traversing filaments; spermatangia in deep pits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Thalli dark reddish brown (not black on drying); usually over 25 cm in length; mostly 2–3 mm in diameter; branching 

irregular, 1–2(–3) orders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. pacifica

4b. Thalli dark brown (black upon drying); 0.3–1.0 m long; 3–4(–5) mm in diameter; branching irregular, 2–5 orders . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. vermiculophylla

5a. Axes subcylindrical to slightly compressed or oval; branching subdichotomous, subsecund, or more or less pinnate . . . . 6

5b. Axes terete, erect, and turgid; branching dichotomous, irregularly or multifariously . . . . . . . . . . . . . . . . . . . . . . . . . . 7

6a. Thallus crisp and usually brittle, axes slightly compressed to oval (in transection), 3–7 mm wide; branching more or less 

pinnate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. pinnata

6b. Thallus not brittle, axes subcylindrical to compressed, up to 3 mm in diameter; branching subdichotomous, distichous, 

up to 7 orders . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. subsecundata
376 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

7a. Terete, of more or less uniform diameter throughout, 1.5–3.0 mm in diameter; dichotomously branched . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. pachydermatica

7b. Thalli not uniform in diameter, either more robust in middle portions or in lower portions . . . . . . . . . . . . . . . . . . . . . 8

8a. Dichotomously branched below, irregularly secund above; axes 1.5–2.0 mm in diameter in lower portions, becoming 

narrower above; cystocarps large compared to branch diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. ramisecunda

8b. Irregularly to subdichotomously branched; robust, turgid axes, 1.5–5.0 mm in diameter; cystocarps small compared to 

branch diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

9a. Thalli usually over 8 cm tall; axes 2–5 mm diameter; infrequently, irregularly branched; cystocarps 700–900 μm in diameter, gonimoblast of large roundish cells, carpospores, 18–20 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . G. turgida

9b. Thalli up to 5.5 cm tall; infrequently subdichotomously branched; axes 1.5–2.0(–3.0) mm in middle portions; cystocarps 

750–800 μm in diameter, gonimoblast of large, elongated cells, larger carpospores, mostly about 30 μm in diameter

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. marcialana

10a. Thalli in unique association with a compound ascidian (tunicate) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. ascidiicola

10b. Thalli free-living, not closely associated with an ascidian . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

11a. Thalli with abundant short, spinose or dentate protuberances on margins and/or on blade surfaces . . . . . . . . . . . . . 12

11b. Thalli either with smooth entire margins or with proliferous outgrowths on margins only (if present, outgrowths not 

spinose or dentate) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

12a. Blades flat, thick (600–1500 μm thick); mostly 5.0–12.0 mm wide; with spinose protuberances on blade surface and 

margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. spinigera

12b. Blades compressed, thin (less than 250 μm thick); less than 5 mm wide; with spinose and dentate protuberances restricted 

to margins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. crispata

13a. Thallus of narrow ligulate branches, 1.5–3.0 mm wide, upper segments tapering to subacute apices . . . . G. tepocensis

13b. Thallus wider, more than 3 mm in width, some over 1 cm or wider (up to 4 cm); apices mostly rounded . . . . . . . . . 14

14a. Thalli less than 8 mm wide; tending to branch more than 1 plane, or with overlapping segments . . . . . . . . . . . . . . . 15

14b. Thallus larger and wider, dichotomously divided in 1 plane; branches generally much broader (especially in middle portions of thallus), and 8.0–50 mm in width . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

15a. Thalli usually over 10 cm tall; branches ligulate, narrow, 3–8 mm wide; dichotomously to subdichotomously branched; 

tetrasporangia in nemathecia-like sori on surface; spermatangia in pit-like cavities . . . . . . . . . . . . . . . G. cunninghamii

15b. Thallus flabellate, up to 8 cm tall, 5–7 mm wide; branched irregularly subdichotomously; tetrasporangia within unmodified cortex; spermatangia in small depressions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. veleroae

16a. Thalli of closely subdichotomously branched, overlapping, upper flattened branches; mostly 1.0–2.5 cm wide; margins 

dentate, with abundant short, finely divided marginal proliferations; ultimate segments sharply reduced in width over 

middle portions; cystocarps less than 900 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. rubrimembra

16b. Thalli flabellate; mostly 2.0–5.0 cm wide; margins lacking dentate or marginal proliferations; upper segments gradually 

reduced in width from middle portions; cystocarps larger, 1.0–1.5 mm in diameter . . . . . . . . . . . . . . . . . . . . G. vivesii

Gracilaria ascidiicola E. Y. Dawson

FIGURE 188

Gracilaria ascidiicola E. Y. Dawson, 1961a:203, pl. 14; 1961b:429; Norris, 1985b:124, fig. 8; González-González et al., 1996:213; CONANP, 

2002:140.

Algae forming sessile lumps or ball-like shapes with a graywhite ascidian (Didemnidae), mostly entangled with and overgrown by ascidian; thalli flat, upper portions protrude about 1–4 

mm above ascidian surface; much branched or a dissected, more 

or less contorted narrow blade, with segments 4–5 mm long, 

2.5–4.0(–5.0) mm wide; margins entire, slightly lobed or undulate; apices broadly rounded. Transection 300–400 μm thick; 

medulla of isodiametric cells, centrally to about 100 μm in diameter, becoming smaller outward to 30–40 μm in diameter below 

thin cortex; cortical layer of 1–2 periclinally elongate pigmented 

cells, 7–16 μm long.

Reproduction unknown.

Habitat. Growing in an ascidian (tunicate, or sea 

squirts) on muddy bottom in ecological association with bryozoans (Bugula sp.) and red algae (Ceratodictyon sp.); shallow 

lagoon; 1–2 m depths.

Distribution. Gulf of California: Estero, innermost lagoon, Puerto Escondido.

Type Locality. Mud bottom, innermost lagoon; 

Puerto Escondido, Baja California Sur, Gulf of California, 

Mexico.

Remarks. Although Gracilaria ascidiicola, when 

cleaned and free of the ascidian, can resemble some forms of G. crispata, it differs in lacking marginal teeth and is thinner in transection, 

with smaller medullary cells and a thinner cortical layer. Reproductive specimens and molecular analyses of G. ascidiicola are needed to 

verify its generic placement and clarify its relationship to G. crispata.
NUMBER 96 • 377

Gracilaria crispata Setchell et N. L. Gardner

FIGURES 189, 190A–D

Gracilaria crispata Setchell et N. L. Gardner, 1924:753, pl. 22: figs. 7–10, 

pl. 44a (holotype); 1930:152; Dawson, 1944a:294; 1949a:26, pl. 

8: fig. 4, pl. 9: figs. 4–10, pl. 10: figs. 5–7; 1957c:20; 1959a:26; 

1961a:205, pl. 10: fig. 13, pl. 11: fig. 9, pl. 12: figs. 15, 16, pl. 15: fig. 

4; 1961b:429; 1961c:415, pl. 24: fig. 2; 1966a:21; Huerta-Múzquiz 

and Tirado-Lizárraga, 1970:128; Chávez-Barrear, 1972b:269; 

Huerta-Múzquiz, 1978:338; Norris, 1985a:93, tbls. 1, 2; 1985b:125, 

fig. 6; Huerta-Múzquiz and Mendoza-González, 1985:50; Mateo-Cid 

and Mendoza-González, 1992:20; Mendoza-González and MateoCid, 1992:19; Serviere-Zaragoza et al., 1993a:483; Mateo-Cid et 

al., 1993:48; León-Tejera and González-González et al., 1993:497; 

Mendoza-González et al., 1994:107; González-González et al., 

1996:213, 393; Riosmena-Rodríguez et al., 1998:27; L. AguilarRosas et al., 2000:130; Cruz-Ayala et al., 2001:191; L. AguilarRosas et al., 2002:234; CONANP, 2002:140; Dreckmann, 2002:95, 

figs.14–20; Pacheco-Ruíz and Zertuche-González, 2002:467; 

Serviere-Zaragoza et al., 2007:10; Pacheco-Ruíz et al., 2008:206; 

Bernecker, 2009:CD-Rom p. 63; Castañeda-Fernández de Lara et al., 

2010:199.

Gracilaria lacerata Setchell et N. L. Gardner, 1924:755, pl. 51c; Dawson, 

1944a:293; González-González et al., 1996:213.

Algae clumped, of several variably branched, narrow, flattened blades, 4–7 cm tall, somewhat “crisped” in upper portions; attached by a small discoid holdfast. Main blades divided 

into few to several flattened axes; these redivided into smaller 

segments becoming progressively shorter and narrower, attenuating upward to narrow, almost terete or spinose ultimate segments. Blade margins with minute, sharp dentition along lower 

portions. Medulla of 3–5 layers of isodiametric cells; up to 200 

μm in diameter. Inner cortex of 2–3 layers of smaller, subcortical cells, merging somewhat abruptly with outer cortex of anticlinal rows of 2–4 cells; outermost surface layer of anticlinally 

elongated pigmented cells. Hairs cells, up to 500 μm long, 

sometimes present; extending from a basal cell within cortex.

Tetrasporangia isolated, scattered throughout cortex, over 

entire blade. Cystocarps protruding, dome shaped, 750–800 μm 

FIGURE 188. Gracilaria ascidiicola: A. Upper portions of G. ascidiicola thalli (arrows) protruding from the sessile ball that is formed in association with an ascidian, a bryozoan, and the red alga Gelidiopsis (isotype: photo of living specimen, EYD-7149, US Alg. Coll.-5690). B. Thallus 

detached from associated organisms (isotype, EYD-7149, US Alg. Coll.-41708). 
378 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

in diameter, with a small rostrum; scattered over upper portions of blades. Gonimoblast of pseudoparenchymatous cells 

developing from a large ramified cell. Carposporangia in chains; 

with traversing (absorbing) filaments to pericarp. Spermatangia (Textorii-type) borne in small, shallow depressions or pits, 

15–25 μm in diameter, separated by rows of elongated cortical 

cells; throughout upper blade segments.

Habitat. On rocks; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Cabeza Ballena; Mazatlán and Bahía 

Topolobampo, Sinaloa to Jalisco. Eastern Pacific: Bahía Tortugas (inside southeast Bahía San Bartolomé), Baja California Sur; 

Isla Clarión (Islas Revillagigedo); Jalisco to Oaxaca; El Salvador; 

Costa Rica.

Type Locality. Rancho Eureka (near Punta Soledad), Bahía de Las Palmas, Baja California Sur, Gulf of California, Mexico.

Remarks. Records of Gracilaria crispata from Peru 

(Acleto O., 1973, 1986) should be critically compared with 

those of the Gulf of California. The minute, whitish to yellowish 

adelphoparasite Gracilariophila gardneri Setchell is sometimes 

found on Gracilaria crispata in the northern Gulf (see Gracilariophila below).

Gracilaria cunninghamii Farlow ex J. Agardh

Gracilaria cunninghamii Farlow ex J. Agardh, 1901:93; Dawson, 

1949a:11, pl. 1: figs. 1–9, pl. 2: figs. 2, 3; pl. 20: figs. 5, 6; Dawson 

et al., 1960a:64, pl. 28: figs. 1, 2; 1960b:13; Acleto O., 1973:52, 

figs. 173, 174; Acleto O., 1986:57, fig. 23; Ramírez and Santelices, 

1991:248; Serviere-Zaragoza et al., 1993a:483; González-González 

et al., 1996:213, 393.

Gracilaria textorii var. cunninghamii (Farlow ex J. Agardh) E. Y. Dawson, 

1961a:213, pl. 10: fig. 1; 1961b:430; Abbott and Hollenberg, 1976:498, 

fig. 444; Abbott, 1985a:97; Mendoza-González and Mateo-Cid, 

1985:30; Mateo-Cid and Mendoza-González, 1994b:40; MendozaGonzález et al., 1994:107; González-González et al., 1996:216.

Tylotus cunninghamii (J. Agardh) Kylin, 1941:22, pl. 8: fig. 20 [“original 

exemplar”].

FIGURE 189. Gracilaria crispata: A. Flat, divided blades with distal “crisped” margins and dome-shaped cystocarps scattered in middle and 

upper portions of thallus (JN-3258, US Alg. Coll.-159559). B. Tetrasporophyte (JN-5866, US Alg. Coll.-159568).
NUMBER 96 • 379

FIGURE 190. Transections of species of Gracilaria. A–D. Gracilaria crispata: A. Mature cystocarp with parenchymatous gonimoblast and 

traversing filaments extending into the pericarp. B. Tetrasporangia within slightly modified cortex. C. Transverse section showing basal cells 

in outer cortex with hairs extending above surface. D. Spermatangia in shallow depressions of outer cortex (A–D after Dawson, 1949a: pl. 9: 

figs. 6, 7, 10; pl. 10: fig. 7). E–G. Gracilaria rubrimembra: E. Mature cystocarp with parenchymatous gonimoblast and numerous traversing 

filaments extending into the pericarp (after Dawson, 1949a: pl. 13: fig. 7). F. Tetrasporangia in modified outer cortex. G. Transection of nonreproductive thallus showing large medullary cells and cortex of small cells (E–G after Dawson, 1949a: pl. 13: figs. 2, 8). H. Gracilaria veleroae: 

Spermatangia in small depressions separated by modified cortical cells (after Dawson, 1949a: pl. 10: fig. 4).
380 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Algae 10–20 cm tall, of flattened, ligulate, irregularly subdichotomously branched fronds; axes and branches 3–8 mm 

wide, 400–600 μm thick; frond narrowly cuneate above a short 

stipitate region, attached below by small discoid holdfast. Medulla of large, thin-walled cells (becoming slightly thicker in 

older lower portions); in transection, inner medullary cells rectangular, with rounded corners, up to 200 μm wide; outer medulla of subcuboidal cells, (15–)20–40 μm in diameter. Cortex 

of 1–2(–3) layers of small, subcuboidal, pigmented cells, 5.0–12 

μm in diameter.

Tetrasporangia cruciately divided; borne within irregularly 

shaped, swollen, nemathecoid sori on the blade surfaces. Cystocarps sessile, globose (sometimes slightly constricted at base), 

with an ostiole; gonimoblast of large cells developed above a 

basal floor of small cells, with traversing (absorbing) filaments 

connecting to pericarp. Spermatangia within deep pit-like cavities within thallus; cavities separated by modified cortical cells.

Habitat. On rocks; low intertidal to shallow subtidal.

Distribution. Gulf of California: San Felipe to 

Guaymas; Mazatlán, Sinaloa to Jalisco. Eastern Pacific: San Luis 

Obispo, central California to Playa Los Cerritos (south of Todos 

Santos), Baja California Sur; Ecuador; Peru.

Type Locality. Santa Barbara, Santa Barbara 

County, southern California, USA.

Remarks. A few Gulf of California specimens are 

tentatively referred to Gracilaria cunninghamii, but the presence 

of this species in the Gulf needs to be molecularly confirmed.

These specimens could be confused with some smaller specimens 

of G. vivesii. Gracilaria cunninghamii is flattened, ligulate, and 

subdichotomously branched, with comparatively narrow segments, 3–8 mm wide, 400–600 μm thick, Whereas the somewhat 

similar G. vivesii is flabellate (not ligulate) and usually larger, 

with much wider segments, (8–)10–50 mm broad, 350–750 μm 

thick. Dawson (1949a) described growth in G. cunninghamii by 

a terminal region of apical filaments (difficult to distinguish a 

single apical cell) that, just a few cells below the apices, develop 

a medulla of compact cells, with the medullary cells attaining 

maximum size within a few millimeters below the apices.

Gracilaria marcialana E. Y. Dawson

Gracilaria marcialana E. Y. Dawson, 1949a:15, pl. 24: fig. 6, pl. 25: figs. 1–6; 

1961a:205, pl. 10: fig. 15, pl. 11: figs. 4, 5, pl. 12: fig. 1; 1961b:429; 

Norris, 1985b:126; Mendoza-González and Mateo-Cid, 1986:424; 

González-González et al., 1996:214; Cruz-Ayala et al., 2001:191; 

CONANP, 2002:140.

Algae of 1 to few (up to 6) erect, turgid, cylindrical axes; 

up to 5.5 cm tall, 1.5–2.0(–3.0) mm in diameter; infrequently, 

subdichotomously branched, 1–2 orders, with terete apices; 

often with few short, sometimes spine-like branchlets; attached 

by a somewhat conical holdfast, irregularly shaped, with short 

prostrate laterals. Cystocarpic thalli more robust and turgid 

than tetrasporangial or spermatangial thalli. Medulla in transection broad, of large, thin-walled cells, 250–300 μm in diameter; outward merging with smaller subcortical cells, 40–70 

μm in diameter. Cortex of 1–2 cell layers, of small irregularly 

shaped, pigmented cortical cells, about 10 μm in diameter 

(these cells sometimes further divided by cell walls in various 

planes). Hair cells deciduous, often only base of hair cell seen 

in cortical layer.

Tetrasporangia ovate, cruciately divided, 30–35 μm in diameter; scattered throughout a very slightly modified cortex. 

Cystocarps protruding, globose, sometimes with a slight basal 

constriction, 750–800 μm in diameter; gonimoblast of large 

elongate cells radiating from fusion cell, connected to pericarp 

by numerous traversing (absorbing) filaments; carposporangia 

about 30 μm in diameter, with a conspicuous stellate central 

body. Spermatangia in irregular shallow depressions (Textoriitype), 20–40 μm in diameter, separated by 1–2 rows of elongated 

cortical cells; spermatia 3–4 μm in diameter; produced on slender, clavate spermatangial parent cells arising from concave floor 

of depression (after Dawson, 1949a, 1961a).

Habitat. Growing on shell and coral fragments in 

reef habitats; subtidal (dredged from 8–30 m depths).

Distribution. Gulf of California: Roca Rojo, 

Bahía Kino; Punta San Marcial, Bahía Agua Verde to Canal de 

San Lorenzo, Isla Espíritu Santo; Bahía de La Paz.

Type Locality. Dredged from 16–30 m depths; 

reef, vicinity of Roca San Marcial, about 2.0 km (~1.25 miles) 

north-northeast of Punta San Marcial (south of Bahía Agua 

Verde), Baja California Sur, Gulf of California, Mexico.

Remarks. Gracilaria marcialana is an endemic species in the Gulf of California. The report of G. marcialana in Pacific Mexico from Colima (Mateo-Cid and Mendoza-González, 

1991) was considered doubtful by Dreckmann (2002).

Although distinctive, the Gulf of California endemic G. 

marcialana remains known from only a few specimens. It somewhat resembles G. turgida in habit, but each is known from 

different ecological habitats: G. marcialana grows in the subtidal on offshore reefs, and G. turgida grows in the intertidal 

on very shallow, muddy, fine-sediment bottom of lagoons and 

esteros. Morphologically, G. marcialana is smaller, up to 5.5 cm 

tall, mostly 1.5–2.0 mm in diameter, with 2–6 axes arising from 

a spreading, irregular discoid to somewhat conical base, infrequently subdichotomously branched, and has cystocarps with 

gonimoblasts of large, elongated cells and larger carposporangia, 

about 30 μm in diameter. In contrast, G. turgida is larger, mostly 

8–15 cm tall, 2.0–5.0 mm in diameter, with 1 to few axes arising 

from a small discoid base, irregularly to subsecundly branched, 

and has cystocarps with gonimoblast cells of large, vacuolated 

cells and smaller carposporangia, 18–20 μm in diameter.

Gracilaria pachydermatica Setchell et N. L. Gardner

FIGURE 191

Gracilaria pachydermatica Setchell et N. L. Gardner, 1924:753, pl. 24: figs. 

30, 31; Dawson, 1944a:294; 1949a:18, pl. 4: figs. 3–6, pl. 5: figs. 3–5, 

pl. 6: figs. 1, 2; 1954e:338; 1957b:26; 1961a:206, pl. 10: fig. 7, pl. 12: 

figs. 9, 10, pl. 15: figs. 1, 2; 1961b:429; 1966a:22; Norris, 1985a:93, 

tbls. 1, 2; 1985b:125, 127, figs. 3, 6; Huerta-Múzquiz and Mendoza-
NUMBER 96 • 381

González, 1985:50; Mendoza-González and Mateo-Cid, 1986:424; 

Serviere-Zaragoza et al., 1993a:483; Mateo-Cid et al., 1993:48; 

Mateo-Cid and Mendoza-González, 1994b:40; González-González et 

al., 1996:214, 393; Mateo-Cid and Mendoza-González, 1997:57: pl. 2: 

figs. 8, 9, pl. 9: fig. 36; Riosmena-Rodríguez et al., 1998:27; Mateo-Cid 

et al., 2000:65; L. Aguilar-Rosas et al., 2000:130; Cruz-Ayala et al., 

2001:191; Dreckmann, 2002:101, figs. 21–26; CONANP, 2002:140; 

L. Aguilar-Rosas et al., 2002:234; Pacheco-Ruíz and ZertucheGonzález, 2002:467; Mateo-Cid et al., 2006:55; Pacheco-Ruíz et al., 

2008:207.

FIGURE 191. Gracilaria pachydermatica: A. Habit (JN-3953, US Alg. Coll.-159595). B. Cylindrical and cartilaginous axes (holotype; modified 

after Setchell and Gardner, 1924: pl. 24: fig. 30). C. Transection showing spermatangia in broad depressions in cortex (after Dawson 1949a: pl. 

4: fig. 4). D. Cystocarp with traversing filaments (after Dawson 1949a: pl. 5: fig. 5). E. Tetrasporangia in outer cortex (after Dawson, 1949a: 

pl. 6: fig. 2).
382 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Gracilaria guaymasensis E. Y. Dawson, 1944a:298, pl. 70, fig. 2 [lower 

right]; González-González et al., 1996:213.

Gymnogongrus sinicola E. Y. Dawson, 1944a:300, pl. 71, fig. 2 [lower left].

Thalli clumped, of few to several rigid, terete axes, 1.5–3.0 

mm in diameter; regularly, repeatedly, dichotomously branched, 

up to 5 times; arising from a discoid holdfast. Branch intervals 

shorter upward; surfaces smooth (without proliferations). Medulla of large, thin-walled, rotund cells to 200 μm in diameter, 

becoming successively smaller outward to subcortex of small 

cells, 10 μm in diameter; outer cortical layer a single row of anticlinally elongated, pigmented cells, about 10 μm long by 5 μm 

wide. Nonpigmented hairs, often present extending from outer 

cortex; basal cell of hairs, larger and different shape than other 

surface cells.

Tetrasporangia ovoid, 30–35 μm long, borne in littlemodified cortex; scattered over upper branches. Cystocarps 

spherical, 750–1000 μm in diameter, with slight basal constriction, ostiolate, rostrate, and borne on upper branches. 

Carposporangia 13–15 μm in diameter; gonimoblast of pseudoparenchymatous cells, with abundant traversing (absorbing) 

filaments to pericarp, developing from a large fusion cell (which 

remains visible in mature cystocarp). Spermatangia borne in 

sunken confluent cavities (Textorii-type) separated by elongated 

cortical cells; over thallus surface.

Habitat. On rocks; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Cabeza Ballena; Sinaloa to Jalisco. 

Eastern Pacific: Isla Cedros (off Baja California); Bahía Sebastián Vizcaino to Playa Los Cerritos (south of Todos Santos), Baja 

California Sur; Oaxaca.

Type Locality. Isla de Tortuga, off Puerto Santa 

Rosalía (about 24.1 km or15 miles NE from Isla San Marcos), 

Baja California Sur, Gulf of California, Mexico.

Gracilaria pacifica I. A. Abbott

Gracilaria pacifica I. A. Abbott, 1985b:116, figs. 2–8; 1985a:97; Scagel et 

al., 1989:187; Stewart, 1991:105; Mendoza-González et al., 1994:107; 

R. Aguilar-Rosas and Aguilar-Rosas, 1994:522; Abbott, 1995:191; 

González-González et al., 1996:217; Cruz-Ayala et al., 2001:191; 

Pacheco-Ruíz et al., 2008:207.

Gracilaria confervoides sensu Dawson, 1949a:13, pl. 15: fig. 9 [non 

Gracilaria confervoides (Linnaeus) Greville, 1830:123; =Gracilaria 

gracilis (Stackhouse) Steentoft, L. M. Irvine et Farnham, 1995:115].

Gracilaria verrucosa sensu Dawson, 1961a:214 [in part; only some Gulf of 

California material]; 1966a:22 [non Gracilaria verrucosa (Hudson) Papenfuss, 1950:195, which is now Gracilaria gracilis (Stackhouse) Steentoft, L. M. Irvine et Farnham, 1995:115; =Fucus gracilis Stackhouse, 

1802:xxx, 100].

Algae of cylindrical, simple to branched axes, 30–100 cm 

long; arising from a small conical holdfast. Habits of two forms: 

(1) in protected habitats, axes 0.5–1.0(–2.0) mm in diameter and 

irregularly branched to 3 orders and (2) differing in exposed 

coastal habitats, with axes 1.5–3.5 mm in diameter and usually 

unbranched or sparsely branched to 1–2 orders (Abbott, 1985b). 

Medulla of large colorless cells, 150–250 μm in diameter, with 

thick cell walls (3.0–10 μm thick); an abrupt transition from medulla to cortex of 2 layers of small pigmented cells.

Tetrasporangia oval, 30–33 μm long by 20–30 μm diameter, borne in modified cortex, scattered over thallus surface of 

main axes and lateral branches. Cystocarps dome shaped to 

globose, protruding, usually less than 1.0 mm (occasionally up 

to 2.0 mm) in diameter. Gonimoblast of very large, thin-walled 

columnar cells, with somewhat weakly developed traversing (absorbing) filaments lateral to carposporangial mass; pericarp of 

brick-like cells. Spermatangia in obovate to somewhat oval pits, 

to 125 μm deep (description after Abbott, 1985a).

Habitat. Usually growing on sandy, fine-sediment 

bottoms; shallow subtidal.

Distribution. Gulf of California: Bahía Kino; 

Bahía San Carlos to Bahía Empalme; Santa Rosalía to Bahía de 

La Paz; Mazatlán. Eastern Pacific: southern British Columbia to 

Baja California.

Type Locality. Intertidal (0.0 ft. tide level); midway to southwest end of Stillwater Cove, Pebble Beach, Monterey County, California, USA.

Remarks. Records of Gracilaria pacifica in the Gulf 

of California are based on the reports of Mendoza-González et 

al. (1994:107), González-González et al. (1996), Cruz-Ayala et 

al. (2001), and Pacheco-Ruíz et al. (2008).

Comparative studies indicated several species may be involved in the “G. verrucosa complex” of similar-looking terete 

taxa (Bird et al., 1982), particularly in the Pacific (Abbott et al., 

1985). “Gracilaria verrucosa” (a name not valid anymore) as 

known from the northeastern Pacific Coast from Alaska to California (Abbott and Hollenberg, 1976) has been shown to correspond to G. pacifica I. A. Abbott (1985b; Scagel et al., 1989; 

Hansen, 1997). Abbott (1985a) noted that in central California 

G. pacifica can be found growing intermixed with northeast Pacific “Gracilaria lemaneiformis,” which is now Gracilariopsis

andersonii (see Gurgel et al., 2003a).

The four species of similar-looking cylindrical specimens of 

Gracilaria and Gracilariopsis from the northern Gulf can be difficult to separate. Two that have spermatangia in pits are species 

of Gracilaria: G. pacifica is generally more robust, with cystocarps having traversing filaments, and G. papenfussii is usually 

shorter and more slender, with weakly developed traversing filaments (sensu Abbott, 1985b:116). In contrast, the spermatangia 

of the other two, Gracilariopsis andersonii and G. animasensis,

are in superficial shallow depressions and have cystocarps that 

lack traversing filaments.

Gracilaria papenfussii I. A. Abbott

Gracilaria papenfussii I. A. Abbott, 1983:562, figs. 1 [holotype], 2, 3; Abbott, 

1985a:97; Stewart, 1991:105; Abbott, 1995:191; González-González 

et al., 1996:217; Cruz-Ayala et al., 2001:191; Riosmena-Rodríguez et 

al., 2005a:33.

Gracilaria andersonii sensu auct. Kylin, 1941:21 [his cited specimens only, 

not including the type; non Gracilaria andersonii (Grunow) Kylin, 
NUMBER 96 • 383

1941:21; in part, only the type specimen of Cordylecladia andersonii Grunow (in Piccone, 1886:63) and none of the other specimens 

cited].

Gracilariopsis andersonii sensu Dawson, 1949a:43 [in part; only his specimens cited]; 1961a:216 [in part; only his specimens cited; non Gracilariopsis andersonii (Grunow) E. Y. Dawson, 1949a:43, only the type of 

Cordylecladia andersonii Grunow (in Piccone, 1886:63), and none of 

the other specimens he cited].

Algae of cylindrical, erect axes up to 15(–18) cm tall, 0.5–

1.0(–1.3) mm in diameter, usually abundantly branched, but irregularly and often unilaterally; above a compact stoloniferous 

base, attached by discoid holdfast. In transection, medulla of 

large, more or less uniform-sized cells; cortex of 2 layers of small 

pigmented cells.

Tetrasporangia oval, scattered in cortex; over thallus surface. Cystocarps protruding, globose to dome shaped, slightly 

rostrate; scattered over thallus; without traversing filaments 

to pericarp. Gonimoblast of very large cells (a character more 

typical of Gracilaria sensu stricto and Hydropuntia Montagne, 

1842d), developing from a conspicuous fusion cell, carposporangia about 20 μm long. Spermatangia within deep pits within 

slightly swollen upper branches.

Habitat. On rocks; mid intertidal to shallow 

subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de La Paz. Eastern Pacific: San Francisco Bay; Santa 

Barbara, southern California to Bahía de Ballena, Baja California Sur.

Type Locality. La Jolla, San Diego County, California, USA.

Remarks. Gracilaria papenfussii has been recorded in 

the Gulf of California by Cruz-Ayala et al. (2001). Specimens that 

were misidentified as “Gracilaria andersonii” by Kylin (1941), 

i.e., only the specimens of Kylin cited in this publication and not 

the type specimen of Cordylecladia andersonii, were considered 

to be distinct from “Gracilaria andersonii” and were described as 

a new species, Gracilaria papenfussii, by Abbott (1983). On the 

other hand, the type material of Cordylecladia andersonii Grunow 

is now Gracilariopsis andersonii (Grunow) E. Y. Dawson.

The taxonomic status of Gracilaria papenfussii is problematic, as there appears to be a reported mixture of spermatangial 

and cystocarpic generic characters. The spermatangia of G. papenfussii were described to be in deep pits, as in Gracilaria (Abbott, 1983:562), but the cystocarps of G. papenfussii were later 

reported (Abbott, 1985a:118) to lack traversing filaments (a character of Gracilariopsis), with a gonimoblast of very large cells (a 

character more typical of Gracilaria sensu stricto and Hydropuntia ). Either this was in error or perhaps the male and females were 

individuals of more than one species or possibly specimens of the 

invasive Gracilaria vermiculophylla were inadvertently included.

Gracilaria (Gracilariopsis?) papenfussii can be confused 

with Gracilariopsis lemaneiformis and Gracilariopsis andersonii (see also Remarks under Gracilaria pacifica). Although 

at one time another common North American terete species,

Gracilariopsis sjoestedii (Kylin) E. Y. Dawson (basionym:

Gracilaria sjoestedtii Kylin), was considered to be identical 

with Gracilaria lemaneiformis (Abbott, 1983), Gurgel et al. 

(2003b), using morphological and molecular analyses, showed 

Gracilariopsis lemaneiformis (Bory) Weber-van Bosse to be restricted in distribution to Pacific South America and showed 

that the similar-looking Gracilariopsis andersonii (including 

G. sjoestedii as a synonym) was a separate species found on 

the northwest Pacific coast of North America. It is difficult to 

distinguish some northern Gulf Gracilaria papenfussii from 

Gracilaria pacifica or some Gracilariopsis andersonii. Abbott 

(1983, as “G. lemaneiformis”) noted G. andersonii to usually 

be 4–8 times longer than G. papenfussii, with much longer lateral branches of similar diameter. When similar morphologies 

of these species are encountered, they can be separated with 

gametangial thalli. The spermatangia are borne in deep pits in 

G. papenfussii and in pyriform pits (about 100 μm deep) in 

California G. pacifica and are distinctly superficial and continuous over the thallus surface in Gracilariopsis andersonii. 

Further, cystocarps of Gracilaria papenfussii lack nutritive 

filaments, but in G. pacifica the traversing filaments are few, 

weakly developed, and usually lateral to carposporophyte. Cystocarps in Gracilariopsis andersonii also completely lack any 

traversing filaments but have superficial spermatangia (characters of Gracilariopsis), which is very different from the reported 

spermatangial pits of Gracilaria papenfussii.

Polne-Fuller and Gibor (1987) showed that southern 

California Gracilaria papenfussii could be induced to produce 

calluses of undifferentiated tissue for culture (see also AguirreLipperheide et al., 1995).

For now, the northern Gulf specimens can only be tentatively referred to G. papenfussii until they can be critically compared to the Gulf’s other cylindrical species and its presence can 

be confirmed. Further, the taxonomic status and generic position 

of the type and type locality specimens of G. papenfussii need to 

be molecularly tested and elucidated.

Gracilaria pinnata Setchell et N. L. Gardner

FIGURE 192

Gracilaria pinnata Setchell et N. L. Gardner, 1924:751, pl. 61; Dawson, 

1944a:294; Norris, 1985a:93, tbl. 1, 2; Norris, 1985b:125, fig. 6; 

González-González et al., 1996:214; Anaya-Reyna and RiosmenaRodríguez, 1996:864, tbl. 1; L. Aguilar-Rosas et al., 2000:130; 

Pacheco-Ruíz and Zertuche-González, 2002:467; Pacheco-Ruíz et 

al., 2008:207.

Gracilaria subsecundata sensu Dawson, 1949a:20 [in part]; 1961a:209 

[in part; non Gracilaria subsecundata Setchell et N. L. Gardner, 

1924:755].

Algae rose red, pinnately branched from more or less distinct 

axes, up to 25 cm tall or more; when fresh, slightly compressed to 

oval in transection, cartilaginous, brittle in texture; 3–4(–7) mm 

wide; branch segments narrowing upward to acuminate apices, 

short marginal laterals present; attachment unknown. Medulla 

of large, thick-walled, colorless cells, grading gradually outward 
384 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

to a 2-layered cortex of small cuboidal to anticlinally elongated 

cells, 10–12 μm long by (3–)5–10 μm in diameter.

Tetrasporangia ovoid, (30–)40–65 μm long by 25–40 μm 

wide; borne deep within subcortex and surrounded by 3–4 

anticlinally elongated cortical cells. Cystocarps dome shaped, 

prominent, up to 1.0 mm in diameter, scattered over thallus; carposporangia (18–)22–30 μm in diameter; gonimoblast of pseudoparenchymatous cells, with traversing (absorbing) filaments to 

pericarp. Spermatangia in shallow depressions (Textorii-type), 

20–22 μm wide by 12–15 μm deep, and separated by anticlinally 

elongated cells; scattered over upper portions of branches. 

Habitat. Clumps of entangled fronds found freeliving on sand plains and sandy bottoms; subtidal, 5–23 m depths.

Distribution. Gulf of California: El Coloradito; 

Puerto Refugio, Isla Ángel de la Guarda to Bahía de Las Ánimas; 

Cabo Pulmo to Los Frailes.

Type Locality. Bahía de Los Ángeles, Baja California, Gulf of California, Mexico.

Remarks. Dawson (1949a) mistakenly concluded that 

Gracilaria pinnata was conspecific with G. subsecundata Setchell et 

N. L. Gardner. However, later comparative morphological analyses 

of newer subtidal collections from Puerto Refugio, Isla Ángel de 

la Guarda (Norris and Bucher, 1976), that were identical with the 

type specimen and topotype specimens (US Alg. Coll.) have shown 

G. pinnata to be a distinct species. Setchell and Gardner (1924) 

probably described their alga from dried herbarium material because freshly collected subtidal specimens are not flat as they noted, 

but rather slightly compressed and oval in transection, 3–4(–7) mm 

wide. The pinnate branching, bright rose red color when fresh, oval 

transection of the axis, and the rigid but brittle nature (easily breaking into pieces when placing specimens into collecting bags) serve to 

distinguish G. pinnata from all other Gulf species.

FIGURE 192. Gracilaria pinnata: Habit (JN-5334, US Alg. Coll.-159632).
NUMBER 96 • 385

Pacific Mexico specimens (AHFH, now UC) identified as 

“Gracilaria pinnata” (Taylor, 1945) were later found to be a new 

species: Sarcodiotheca taylorii E. Y. Dawson (1961a).

Gracilaria ramisecunda E. Y. Dawson

FIGURE 193

Gracilaria ramisecunda E. Y. Dawson, 1949a:17, pl. 3: figs. 1–8; pl. 4: figs. 

1, 2; pl. 5: figs. 1, 2; 1959b:26; 1961a:207, pl. 10: fig. 12, pl. 12: fig. 

2, pl. 15: fig.3; 1961b:429; 1966b:64; Norris, 1985b:128, fig. 14; 

González-González et al., 1996:214; Mendoza-González and MateoCid, 1999:43, figs. 10–13; CONANP, 2002:140.

Algae erect, usually a single main axis, cylindrical to 

slightly compressed, robust and rigid, mostly 6–8 cm tall; basal 

portion 1.5–2.0 mm in diameter and up to 7 mm long, tapering upward to upper portions of 400–1000 μm in diameter, 

with blunt apices; branching mostly 3–4 orders; first 2 orders 

FIGURE 193. Type collection of Gracilaria ramisecunda: A. Habit of tetrasporangial alga (after Dawson 1949a: pl. 3: fig. 1). B. Part of a cystocarpic thallus (after Dawson 1949a: pl. 4: fig. 1). C. Transection of axis showing gradual transition from cortex to medulla. D. Transection of 

a tetrasporic branchlet showing modified cortex. E. Transection of spermatangial thallus showing spermatangia in shallow pits. F. An example 

of a carpogonial branch; others may bear more or fewer branches off carpogonial branch cells (C–F after Dawson 1949a: pl. 3: figs. 4–6, 8). 

G. Transection of bearing branch and mature cystocarp showing the fusion cell, pseudoparenchymatous gonimoblast, and numerous traversing 

filaments to the pericarp (After Dawson, 1949a: pl. 5: fig. 2).
386 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

irregularly subdichotomous, usually with long intervals between branches; second 2 orders irregular, tending to secund, 

with intervals of about 0.5–1.5 cm; attached by discoid holdfast. Medulla in transection of 8–10 rotund to ovoid cells, 

40–60(–100) μm in diameter; subcortex of 2 layers of cells 

about 12–22 μm in diameter. Outer cortex a single layer of 

anticlinally elongate cortical cells, (6–)10–15 μm in diameter; 

with some basal cells of hairs. In longitudinal section, 2-layer 

subcortex of isodiametric cells very distinct from longitudinally 

elongated medullary cells.

Tetrasporangia cruciately divided, ovoid, 30–40 μm tall, 

15–25(–35) μm in diameter; in slightly modified cortex of anticlinal elongate cells; scattered in upper branches. Cystocarps 

subglobose, (550–)600–1200 μm in diameter, sessile with a slight 

basal constriction; ostiolate; scattered, protruding on branches 

in upper thallus; gonimoblast of pseudoparenchymatous cells 

above a conspicuous fusion cell, with traversing (nutritive) filaments to pericarp; carposporangia 14–17 μm in diameter. Spermatangial thalli compressed; spermatangia (Textorii-type) in 

small sunken depressions separated by anticlinally elongated 

cortical cells.

Habitat. On rocks and in tide pools; low intertidal.

Distribution. Gulf of California: Puerto Escondido to Cabeza Ballena. Eastern Pacific: Oaxaca.

Type Locality. Intertidal; Cabeza Ballena, Baja 

California Sur, Gulf of California, Mexico.

Gracilaria rubrimembra E. Y. Dawson

FIGURES 190E–G, 194

Gracilaria rubrimembra E. Y. Dawson, 1949a:32, pl. 13: figs. 1–8; 1961a:208, 

pl.10: fig. 11, pl. 13: fig. 2 [type collection]; 1966a:22; 1966b:64; Norris, 1985a:93, tbls. 1, 2; Norris, 1985b:129, fig. 2; González-González 

et al., 1996:215, 350: fig. 29, 394; Riosmena-Rodríguez et al., 1998:27; 

Pacheco-Ruíz and Zertuche-González, 2002:467; Pacheco-Ruíz et al., 

2008:207.

Algae of 1 to few dull red, complanate, subflabellate, membranous blades, up to 2.5 cm in width (broadest in middle 

portions of thallus); irregularly subdichotomously to polychotomously branched in 1 plane; lower portions of blade narrowing basally to a short, compressed stipe, 1.0 mm in diameter, 

attached below by a discoid holdfast. Upper portions congested 

and overlapping; margins with numerous short, divided, pointed 

or lobed, lateral proliferations. Transection 700–850 μm thick. 

Medulla of large, thin-walled cells, 120–160 μm in diameter, 

grading to smaller inner cortical cells, 20–25 μm in diameter, and 

outward to outer cortex of 1–2 layers of small, variously shaped 

pigmented cells, 8.0–15 μm in diameter.

Tetrasporangia 20–30 μm in diameter, embedded within 

inner cortex, surrounded by 2–4 filamentous cells (which are 

modified inner and outer cortical cells). Cystocarps dome 

shaped, projecting, up to 900 μm in diameter, ostiolate, slightly 

rostrate; scattered over upper portion of blade surfaces. Gonimoblast developing from a branched fusion cell; composed of 

pseudoparenchymatous cells above a dome of medullary cells, 

with numerous traversing (absorbing) filaments to pericarp. 

Spermatangia unknown.

Habitat. On rocks; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas; Isla San Pedro Mártir.

Type Locality. South side of Ensenada de San 

Francisco, near Puerto San Carlos, Sonora, Gulf of California, 

Mexico.

Remarks. Gracilaria rubrimembra is another endemic species in the Gulf of California. Dreckmann (2002) noted 

the report of G. rubrimembra from Nayarit to Jalisco (ServiereZaragoza et al., 1993a) needs to be verified.

Gracilaria spinigera E. Y. Dawson

FIGURES 195, 196

Gracilaria spinigera E. Y. Dawson, 1949a:24, pl. 8: figs. 1–3, pl. 9: figs. 1–3; 

1959a:26, fig. 5; 1961a:208, pl. 12: fig. 6, pl. 16; 1961b:429; Norris, 1985b:129, fig. 15; Mateo-Cid and Mendoza-González, 1992:20; 

Serviere-Zaragoza et al., 1993a:483; González-González et al., 

1996:214, 394; Anaya-Reyna and Riosmena-Rodríguez, 1996:864, tbl. 

1; Riosmena-Rodríguez et al., 1998:27; Cruz-Ayala et al., 2001:191; 

CONANP, 2002:140; Pacheco-Ruíz and Zertuche-González, 

2002:467; Hernández-Herrera et al., 2005:147.

Algae of several branched, complanate blades, up to 15 cm 

tall; blades (3.5–)5.0–12.0 mm in width (broadest in upper portions), narrowing downward to a cuneate base above a stipe-like 

or abruptly contracted basal portion; attached by a small discoid holdfast. Primary branching subdichotomous, often closely 

set; apical portion with several spinose terminal segments. Secondary branches short, marginal spinose branchlets, 4–12 mm 

long. Transection 600–1500 μm thick. Medulla of large cells, 

150–180 μm in diameter, grading into subcortical layer of cells, 

25–50 μm in diameter; outer cortex a single layer of small, anticlinally elongated cells.

Tetrasporangia 20–25 μm in diameter, embedded in littlemodified cortex of anticlinal oblong cells, 10–14 μm long; 

scattered over blade. Cystocarps globose, barely rostrate, 1.2–

1.5 mm in diameter, individually scattered on blade surfaces; 

or clustered and congested among spines of branchlets and 

400–600 μm in diameter. Gonimoblast of large pseudoparenchymatous cells, with numerous traversing (absorbing) filaments 

to thick-walled pericarp. Spermatangia in closely spaced ovoid 

cavities (Verrucosa-type), 35–60 μm deep by 28–45 μm wide, 

with a surface opening up to 20 μm in diameter.

Habitat. On rocks; intertidal to shallow subtidal.

Distribution. Gulf of California: Bahía de Los 

Ángeles to Guaymas; Puerto Escondido; Isla Carmen; Bahía de 

La Paz; Cabo Pulmo to Los Frailes.

Type Locality. Ensenada de San Francisco (vicinity 

Puerto San Carlos), Sonora, Gulf of California, Mexico.

Remarks. Gracilaria spinigera is distinguished from 

other Gulf species of Gracilaria by its flattened, “gigartinoidchondracanthoid” appearance and its deep spermatangial cavities. Dawson (1961a) suggested smaller specimens from Isla Santa 
NUMBER 96 • 387

FIGURE 194. Gracilaria rubrimembra, two specimens showing morphological variability: A. Flat and wide thallus. B. Thallus with numerous 

finely divided and somewhat dentate marginal proliferations (A, B, both JN-3032: A, US Alg. Coll.-159638; B, US Alg. Coll.-159637). 
388 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Margarita (Pacific Mexico) may also be this species, but Dreckmann (2002) stated that the Pacific Mexico reports of “G. spinigera” from Nayarit (Mateo-Cid and Mendoza-González, 1992) 

and Jalisco (Serviere-Zaragoza et al., 1993a) corresponded with 

other species. The reports from Pacific Costa Rica (Bernecker 

and Wehrtmann, 2009; Fernández-García et al., 2011) and the 

Philippines (Silva et al., 1987) should also be reinvestigated to 

confirm their identifications.

Gracilaria subsecundata Setchell et N. L. Gardner

FIGURE 197A,B

Gracilaria subsecundata Setchell et N. L. Gardner, 1924:755, pl. 23: figs. 26, 

27, pl. 59; Dawson, 1944a:294; 1949a:20, pl. 6: figs. 3–11, pl. 7: figs. 

1–9; 1959a:26; 1961a:209, pl. 10: fig. 10, pl. 11: figs. 1, 6, pl. 12: figs. 

3, 4, pl. 17; 1966a:22; Norris, 1973:13; Huerta-Múzquiz, 1978:336; 

Norris, 1985a:93, tbls. 1, 2; Norris, 1985b:131, fig. 7; MendozaGonzález and Mateo-Cid, 1986:424 [with a query]; Serviere-Zaragoza 

et al., 1993a:483; Mateo-Cid et al., 1993:47; González-González et al., 

1996:215, 394; Riosmena-Rodríguez et al., 1998:27; L. Aguilar-Rosas 

et al., 2000:130; Cruz-Ayala et al., 2001:191; CONANP, 2002:140; 

L. Aguilar-Rosas et al., 2002:234; Pacheco-Ruíz and ZertucheGonzález, 2002:467; Pacheco-Ruíz et al., 2008:207.

Gracilaria compressa sensu Dawson, 1944a:296 [in part; non Gracilaria 

compressa (C. Agardh) Greville, 1830:125; =Gracilaria bursa-pastoris

(S. G. Gmelin) P. C. Silva, 1952:265]. 

Gracilaria pinnata sensu Dawson, 1961a:209 [in part; non Gracilaria pinnata Setchell et N. L. Gardner, 1924:751].

Algae bushy when small, becoming more or less laxly 

branched with growth; subcylindrical to compressed branches, 

up to 25 cm tall, (2–)3 mm in diameter; branching sparse to 

FIGURE 195. Gracilaria spinigera: Habit (EYD-10986, US Alg. Coll.-7536).
NUMBER 96 • 389

dense, usually subdichotomous, up to 6–7 orders; can become 

more or less alternate, pinnate, or secund with growth; arising 

from a small discoid holdfast. Branches attenuating upward to 

acute tips; branch internodes variable with size and age, from 

about 3 mm in small or densely branched thalli, and 1–6 cm in 

larger thalli. Medulla of large rotund cells, about 200 or more 

μm in diameter, grading into radially elongate subcortical cells, 

25 μm in diameter. Outer cortex of 2–3 angular to elliptic pigmented cells, mostly up to 10 μm long by 5–8 μm wide; tending 

to be anticlinally arranged. Hairs sometimes present, conspicuous; or only the basal cells of hairs within outer cortex.

Tetrasporangia ovoid, cruciately divided and, 25–30(–45) 

μm in diameter, but some sporangia divided periclinally to produce bispores; within modified cortex of irregular, small cells organized in anticlinal rows of 3–4 cells (outermost cell elongated); 

scattered over branch surfaces. Carpogonial branch 2-celled. 

Cystocarps dome shaped (not constricted), ostiolate, scattered 

over upper portions of thallus. Gonimoblast broad based, of 

pseudoparenchymatous cells, developed from a large fusion cell, 

with many traversing (absorbing) filaments to pericarp. Spermatangia in sunken depressions (Textorii-type), 14–17 μm in diameter, containing 8–20 spermatangial parent cells; depressions 

separated by bands of cortical cells, usually in groups over 

branch surfaces.

Habitat. On rocks or sand-covered substrate, often 

found in bays and estuaries; mid intertidal to shallow subtidal.

Distribution. Gulf of California: Piedras del Burro 

(Gulfo de Santa Clara) to Bahía Agua Verde; Isla Espiritu Santo 

to Bahia de La Paz; Bahía Topolobampo.

Type Locality. Guaymas, Sonora, Gulf of California, Mexico.

Remarks. Collection and examination of tetrasporangial Gracilaria subsecundata will be helpful to determine if 

the reported bispores (Dawson, 1949a) are viable or if they are 

immature tetrasporangia. Gracilaria subsecundata is probably 

endemic in the Gulf of California. Dreckmann (2002) noted that 

reports of G. subsecundata from Nayarit (Serviere-Zaragoza et 

al., 1993a) and in Pacific Mexico from Colima (Mateo-Cid and 

Mendoza-González, 1991) were doubtful.

Gracilaria tepocensis (E. Y. Dawson) E. Y. Dawson

FIGURE 198A

Rhodymenia? tepocensis E. Y. Dawson, 1944a:307 [with generic query], pl. 

65: fig. 1. 

FIGURE 196. Gracilaria spinigera: A. Habit. B. Branching in terminal portion of specimen (A, B after Dawson 1949a: 

pl. 8: figs. 1, 2). C. Longitudinal section of spermatangial cavity (holotype; after Dawson 1949a: pl. 8: fig. 5). D. Transection of tetrasporangial thallus. E. Transection of dried specimen (D, E after Dawson, 1949a: pl. 9: figs. 2, 3).
390 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Gracilaria tepocensis (E. Y. Dawson) E. Y. Dawson, 1961a:211; 1961b:430; 

1966b:64; Norris and Bucher, 1976:17; Huerta-Múzquiz, 1978:339; 

Norris, 1985b:131, fig. 13; Mendoza-González and Mateo-Cid, 

1985:30; González-González et al., 1996:215, 394; Aguilar-Rosas et 

al., 2000:130; Pacheco-Ruíz et al., 2008:207.

Algae lax, of few to several narrow, complanate, subdichotomously branched fronds, up to 25.5 cm long and 2.0–3.0(–5.5) 

mm wide, attached by a small discoid holdfast. Fronds repeatedly 

branched in 1 plane, up to 3–4 orders, at intervals of 1–2(–6) cm; 

margins entire, smooth; upper branches reduced in width upward to either a blunt apex or to apices of two or more digitate 

segments. Transection (150–)200–300 μm thick. Medulla narrow, of 2 layers of large cells, 100–200 μm in diameter, abruptly 

adjoined to a thin, completely or partially developed subcortical 

layer of smaller cells. Outer cortex usually a single layer of periclinally elongated, pigmented cells, 7–10(–20) μm in diameter.

Tetrasporangia about 20 μm in diameter; borne in slightly 

modified cortex of 2-celled anticlinal filaments (not always evident); scattered over thallus. Cystocarps globose, up to 500 μm 

in diameter, rostrate; borne on thallus margins or over surface. 

Gonimoblast of radially elongated pseudoparenchymatous cells, 

developing from a large fusion cell; with numerous traversing 

(absorbing) filaments to pericarp. Spermatangia (Textorii-type) 

in small, partially sunken, irregularly confluent sori, bordered by 

little-modified to anticlinal elongate cortical cells; spermatia 3–4 

μm in diameter.

Habitat. On rocks; subtidal, down to 4.5–21 m 

depths.

Distribution. Gulf of California: San Felipe to 

Puertecitos; Bahía Tepoca to Bahía Agiabampo; Puerto Refugio, 

Isla Ángel de la Guarda to Isla Estanque (Islas de la Cintura); 

Bahía de Los Ángeles.

Type Locality. Bahía Tepoca, Sonora, Gulf of California, Mexico.

Remarks. Gracilaria tepocensis was originally 

known only from dredged material from Bahía Tepoca, Isla Estanque (Dawson, 1944a, 1961a), and Agiabampo, Sonora (Dawson, 1966b). Our diving surveys yielded numerous collections of 

G. tepocensis from the shallow subtidal to 11 m depths, Puerto 

Refugio, Isla Ángel de la Guarda (Norris and Bucher, 1976). The 

reported depths of the dredged specimens (Dawson, 1961a), particularly the one from 113 m, are doubtful for attached, growing 

FIGURE 197. Species of Gracilaria. A, B. Gracilaria subsecundata: A. Habit of male gametophyte. B. Habit, a nonreproductive thallus (A, B, 

JN-4990, US Alg. Coll.-159647). C. Gracilaria veleroae: Habit, specimen from the type collection (EYD-141a-40, AHFH-37, now UC).
NUMBER 96 • 391

FIGURE 198. Species of Gracilaria. A. Gracilaria tepocensis: Habit (JN-5356, US Alg. Coll.-156380). B. Gracilaria turgida: Habit of female 

gametophyte with cystocarps (JN-3212, US Alg. Coll.-159687).
392 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

intact specimens. It is possibly an endemic in the Gulf of California, but this awaits molecular and morphological comparisons.

Although the Pacific Costa Rican G. crockeri E. Y. Dawson (1949a) has been considered conspecific (Dawson, 1961a), 

its relationship to the northern Gulf G. tepocensis needs to 

be reinvestigated. Reports of G. tepocensis from Pacific Mexico (Pedroche and González-González, 1981; Mateo-Cid and 

Mendoza-González, 1991) were noted by Dreckman (2002) as 

doubtful. Those of León-Tejera and González-González (2000, 

as “Gracilaria aff. tepocensis”), as well as records from El Salvador (Fernández-García et al., 2011), Costa Rica (Bernecker, 

2009), and Peru (Acleto O., 1973, 1986) should also be reexamined to verify their identity.

Gracilaria turgida E. Y. Dawson

FIGURE 198B

Gracilaria turgida E. Y. Dawson, 1949a:14, pl. 21: figs. 1–11, pl. 24: fig. 

1; 1961a:213, pl. l0: figs. 5, 6, pl. 12: fig. 11, pl. 24: fig. 1; 1966a:22; 

1966b:63; Abbott and Hollenberg, 1976:498, fig. 445; R. AguilarRosas, 1982:84; Norris, 1985a:94, tbls. 1, 2; Norris, 1985b:132, 

fig. 5; Huerta-Múzquiz and Mendoza-González, 1985:50; Ortega 

et al., 1987:72, pl. 3: fig. 18, pl. 4: figs. 19, 20; Sánchez-Rodríguez 

et al., 1989:44; González-González et al., 1996:216; Mateo-Cid et 

al., 2000:65; L. Aguilar-Rosas et al., 2000:130; Cruz-Ayala et al., 

2001:191; CONANP, 2002:140; L. Aguilar-Rosas et al., 2002:234; 

Pacheco-Ruíz and Zertuche-González, 2002:467; Riosmena-Rodríguez 

et al., 2005a:33; Pacheco-Ruíz et al., 2008:207; R. Aguilar-Rosas et al., 

2009:6, fig. 2e.

Algae cylindrical, robust, turgid and succulent; sometimes 

somewhat brittle and light brown to pale brownish red when 

fresh; of 1 to several axes, up to 15 cm tall, 2–5 mm in diameter; 

sparsely, irregularly branched, 1–2(–3) times, with terete, blunt 

apices; attached below by a discoid holdfast. Medulla of large, 

thin-walled cells, grading outward to the cortex of small, rotund 

cells; outer cortex usually a single layer of smaller, somewhat 

anticlinally elongated, pigmented cells; often with numerous, deciduous hairs present in cortical layer.

Tetrasporangia borne in more or less modified cortex, scattered throughout thallus. Cystocarps globose, (500–)700–900 

μm in diameter, prominent, ostiolate, to some extent basally 

constricted, scattered on upper thallus; carposporangia 18–20 

μm diameter. Gonimoblast of large vacuolated cells, with numerous traversing (absorbing) filaments to pericarp. Spermatangia 

within shallow, cup-shaped depressions (Textorii-type) separated 

by modified anticlinally elongated cortical cells; in cortical layer.

Habitat. On shells or rocks, in mudflats, lagoons, 

and estuaries, often in tidal drainage channels; intertidal.

Distribution. Gulf of California: Punta Gorda 

(Gulfo de Santa Clara) to Bahía La Choya (Bahía Cholla, vicinity of Puerto Peñasco); El Coloradito; Estero de Bahía de Las 

Ánimas to Cabo Pulmo; Laguna de Agiabampo; lagunas from 

Navachiste to Santa María–La Reforma. Eastern Pacific: southern California; Estero de Punta Banda, Baja California to Bahía 

Magdalena, Baja California Sur.

Type Locality. Mudflat, upper Newport Harbor, 

Newport–Balboa, Orange County, California, USA.

Remarks. Gracilaria turgida seems to prefer, or is 

possibly restricted to, the protected habitats of lagoons, esteros, 

mudflats, and salt marshes.

Gracilaria veleroae E. Y. Dawson

FIGURES 190H, 197C

Gracilaria veleroae E Y. Dawson, 1944a:297, pl. 70: fig. 2 [left: type 

specimen]; Dawson, 1946:83; 1949a:28, pl. 2: figs. 7, 8, pl. 10: 

figs. 1–4; 1961a:214, pl. 10: figs. 2, 3, pl. 12: fig. 5, pl. 19: fig. 1; 

1961b:430; Abbott and Hollenberg, 1976:499, fig. 446; L. AguilarRosas, 1981:94; Huerta-Múzquiz and Mendoza-González, 1985:50; 

Abbott, 1985a:98; Norris, 1985b:132; Sánchez-Rodríguez et al., 

1989:44; Serviere-Zaragoza et al., 1993a:483; Mateo-Cid et al., 

1993:48; González-González et al., 1996:216, 394; Mateo-Cid et 

al., 2000:65; L. Aguilar-Rosas et al., 2000:130; León-Tejera and 

González-González, 2000:327 [as G. aff. veleroae]; CONANP, 

2002:140; Dreckmann, 2002:104, figs. 27–32; Serviere-Zaragoza et 

al., 2007:10; Pacheco-Ruíz et al., 2008:207; Castañeda-Fernández de 

Lara et al., 2010:199.

Gracilaria tenuifolia W. R. Taylor, 1945:234, pl. 78: fig. 1.

Gracilaria johnstonii sensu Taylor, 1945:9 [in part; non Gracilaria johnstonii

Setchell et N. L. Gardner, 1924:752 9, which is now Gracilaria vivesii 

M. Howe, 1911:503].

Algae of compressed, membranous, flabellate blades, up to 

8 cm tall; dichotomously to subdichotomously branched, 3–5 

orders; branches 5–7 mm wide, with entire smooth margins and 

rounded apices, narrowing downward, becoming more or less 

cuneate above a small discoid holdfast. Transection usually less 

than 250 μm thick (occasionally 300– 400 μm thick). Cortex a 

single layer of periclinally flattened, pigmented cells, 5(–9) μm 

tall by 12–13 μm wide.

Tetrasporangia spherical, 25–35 μm in diameter, borne 

within barely modified cortex; scattered over thallus. Cystocarps 

dome shaped, up to 1000 μm in diameter, ostiolate, slightly rostrate; usually near blade margins. Gonimoblast of large pseudoparenchymatous cells, developing from a large fusion cell, 

with numerous traversing (absorbing) filaments to pericarp. 

Spermatangia in small, shallow depressions (Textorii-type), 

sometimes becoming partially confluent; depressions separated 

by anticlinally elongate cells; scattered over blade surfaces; spermatia 2.5–3.0 μm in diameter.

Habitat. On rocks; subtidal 4–30(–79) m depths.

Distribution. Gulf of California: Punta Peñasco to 

Cabeza Ballena; Nayarit. Eastern Pacific: La Jolla, southern California to Bahía Magdalena, Baja California Sur; Isla Socorro and 

Isla Clarión (Islas Revillagigedo); Guerrero; Galápagos Islands.

Type Locality. Dredged 4–30 m depths; near Isla 

Turner, off the southern shore of Isla Tiburón (Islas de la Cintura), Gulf of California, Mexico.

Remarks. Some specimens of Gracilaria veleroae

can superficially resemble smaller specimens of G. cunninghamii, but these can be easily separated anatomically. Gracilaria 
NUMBER 96 • 393

veleroae is typically much thinner in transection (mostly less 

than 250 μm thick) and membranous, whereas G. cunninghamii

is thicker (400–600 μm) and coriaceous. The tetrasporangia of 

the G. veleroae are borne in a barely modified cortex and are 

spherical and larger (25–35 μm in diameter) compared to those 

of G. cunninghamii, which are in a modified cortex and smaller, 

15–22 μm in diameter (Dawson, 1949a, 1961a; Norris, 1985b).

Gracilaria vermiculophylla (Ohmi) Papenfuss

Gracilariopsis vermiculophylla Ohmi, 1956:271, figs. 1–4, pls. 1, 2; 1958:46.

Gracilaria vermiculophylla (Ohmi) Papenfuss, 1967:101; Yamamoto, 

1978:130, pl. 28: figs. 1–7, pl. 29: figs. 1–6, pl. 47: figs. 2, 3; Xia and 

Yamamoto, 1985:69; Yamamoto, 1985:77, tbls. 1, 2, fig. 12; Abbott, 

1995:194; Yoshida and Yamamato, 1998:825, fig. 3-73B,C; Terada 

and Yamamoto, 2002:215, figs. 1 (holotype), 2 (isotype), 3–13; Bellorin et al., 2004:70, figs. 1–24; Piñón-Gimate et al., 2008:116; OrduñaRojas et al., 2008:503; M.-S. Kim et al., 2010:393, 398, figs. 21–26.

Gracilaria asiatica Zhang et B.-M. Xia, 1985:175, figs. 1–2; Nguyên, 

1992:207; Terada and Yamamoto, 2002:216.

Gracilariopsis rhodotricha sensu Ohmi, 1958:47, fig. 2, pl. 10; Nguyên, 

1992:207 [non Gracilariopsis rhodotricha E. Y. Dawson, 1949a:47].

Gracilaria pacifica sensu R. Aguilar-Rosas et al., 1993:219; Pacheco-Ruíz et 

al., 1993:491; Garza-Sánchez et al., 2000:205 [non Gracilaria pacifica

I. A. Abbott, 1985b:116].

Algae of slender, cylindrical axes, dark brown (drying black), up to 30(–100) cm long, 1–2(–3) mm in diameter; 

branching unilaterally or alternately at irregular intervals, 2–5 

orders; branches tapering near apices; attached by small discoid 

holdfast or unattached. In transection, cell size transition from 

medulla to cortex gradual. Medulla 4–5(–12) layers of large elliptical cells, 34–410 μm by 12–25 μm, with abundant starch 

grains and thick cell walls, 12–20 μm. Cortex mostly of 3–4 

layers of pigmented cells (up to 8 layers in tetrasporangial and 

spermatangial basal regions); inner cortex 3–5 layers of radially elongated cells; outer cortical cells, 7–18 μm tall, 3–8 μm 

wide. Cortical hairs, usually near apices, deciduous; hair basal 

cell persistent, multinucleate.

Asexual reproduction by fragmentation. Tetrasporangia 

elongate, decussate-cruciately or irregularly divided; up to 65 μm 

long, 30–45 μm in diameter; produced within cortex; surrounded 

by anticlinally elongated cortical cells. Carpogonial branches 

2-celled, with short trichogynes; developed from outer cortical 

cell, supporting 2 short sterile filaments. Fusion cell “star-like” 

(seen only in early development stages), produces gonimoblast 

initials. Gonimoblast large, of small, densely protoplasmic cells. 

Cystocarp floor bears carposporangia initials and a few traversing (absorbing) filaments. Pericarp of 3–4 outer layers of rounded 

cells, with terminal cells radially elongated, 7–17 μm long, 5–10 

μm in diameter, without secondary pit connections; middle layer 

of 6–10 cells, star shaped because of abundant secondary pit 

connections; innermost layer of 1–4 rounded cells in chains, each 

with only a single pit connection. Spermatangial conceptacles 

usually single, sometimes coalescing; initially, conceptacles may 

initially be shallow depressions with spermatangia restricted to 

cavity floor; later, as development continues, becoming deeper, to 

90(–120) μm in depth, 60–80 μm in diameter (Verrucosa-type), 

with spermatangia on both floor and walls of cavity. Spermatangium cut off by oblique division of a spermatangial parent cell. 

(Reproduction after Bellorin et al., 2004:73.)

Habitat. On rocks, pebbles, and shells, usually partially covered in fine sediments or mud, or may be unattached 

and free-floating; in coastal rivermouths, lagoons, esteros, and 

protected shallow bays; intertidal.

Distribution. Gulf of California: Laguna Ohuira 

and Bahía de Navachiste to Teacapán, Sinaloa. Eastern Pacific: 

Elkhorn Slough, central California to Estero de Punta Banda, 

northern Baja California. Western Pacific: China; Korea; Japan; 

Vietnam.

Type Locality. Gomejima, Akkeshi-ko Lagoon 

(shallow estuary connected to shore of Akkeshi Bay), Kushiro 

Province (now Kushiro Subprefecture), Hokkaidō Island, Japan.

Remarks. The Japanese Gracilaria vermiculophylla

(Ohmi) Papenfuss is an agarophyte known in the northwestern 

Pacific (Yamamoto, 1985; Yoshida, 1998; Tseng and Xia, 1999; 

M.-S. Kim et al., 2010). It was apparently introduced over 30 

years ago to the northeastern Pacific as early as 1981 in Elkhorn 

Slough, Monterey Bay, California (e.g., US Alg. Coll.-094794). 

Within the last 20 years, G. vermiculophylla has been recorded 

in the northeastern Pacific from northern Baja California and central California (Bellorin et al., 2004; Miller et al., 2011) and British Columbia (Saunders, 2009). It is recognized to be an invasive 

species introduced in the Eastern Pacific and Eastern and Western 

Atlantic on numerous occasions by the shipping and importation 

of Japanese oysters to North America and Europe (e.g., Bellorin et 

al., 2004; Rueness, 2005; Thomsen et al., 2006; Freshwater et al., 

2006; S.-Y. Kim et al., 2010), or possibly as a component of seaweed/seagrass mixture used as commercial soil conditioner (Abreu 

et al., 2011). Its success as an invasive species and known habitat 

modifier (Wallentinus and Nyberg, 2007; Williams and Smith, 

2007) has raised ecological and environmental concerns. Genetic 

data support the hypothesis that the Sea of Japan (East Sea) populations of G. vermiculophylla were the probable source of the 

invasive species to Pacific North America (S.-Y. Kim et al., 2010).

Gracilaria vermiculophylla has been recently reported in the 

southern Gulf from Ohuira, Navachiste, and Santa María-La 

Reforma, Sinaloa (Orduña-Rojas et al., 2008; Piñíon-Gimate et 

al., 2008, 2012). The highest biomass of this nonnative species 

was found in laguna Santa María-La Reforma, with high nutrient concentrations attributed to sewage affulents and where it 

increased from the dry to rainy seasons with the highest temperatures and decreased during the cold season (Piñón-Gimate et al., 

2008, 2012). The highly invasive G. vermiculophylla needs to be 

monitored as it may also be elsewhere in the Gulf of California.

Although cystocarps of Gracilaria vermiculophylla were 

originally described by Ohmi (1956, as Gracilariopsis vermiculophylla) as lacking traversing filaments, these were observed 

to be generally rare but present in type locality material (Yamamoto, 1978); this was similarly observed in southern Gulf of 
394 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

California material by Bellorin et al. (2004). In the Akkeshi-ko 

lagoon (type locality) G. vermiculophylla grows sympatrically 

with Japanese “G. verrucosa,” a species with which it shares 

similar spermatangial conceptacles, and also with Gracilariopsis chorda (Holmes) Ohmi (1958), which has similar cystocarps (but very different spermatangial structures). Yamamoto 

(1985:131) suggested that G. vermiculophylla may possibly be 

a hybrid between these two. However, molecular phylogenetic 

analyses based on rbcL gene sequences conducted by Gurgel and 

Fredericq (2004) clearly demonstrated that G. vermiculophylla, 

together with G. tenuistipitata C. F. Chang et B.-M. Xia (1976)

and G. chilensis C. J. Bird, McLachlan et E. C. Oliveira (1986), 

formed a distinct evolutionary lineage, showing that they need to 

be recognized as a new and distinct genus.

All cylindrical species of Gracilaria reported in the northern 

Gulf, i.e., G. vermiculophylla, G. pacifica, and G. papenfussii, 

are in need of further morphological comparisons and clarification based on molecular analyses with type locality specimens of 

each species. Gracilaria vermiculophylla, although often difficult 

to identify solely by morphology, can be accurately identified 

using molecular techniques. The mtDNA barcode marker cox1 

enables analysis of intraspecific genetic diversity and haplotype 

richness (Gulbransen et al., 2012) and for comparing native and 

non-native species.

Gracilaria vivesii M. Howe

FIGURE 199

Gracilaria vivesii M. Howe, 1911:503, pls. 30, pl. 33: figs. 1–5; Setchell and 

Gardner, 1924:750; Dawson, 1949a:34, pl. 2: figs. 4–6, pl. 14: figs. 

1–6, pl. 15: figs. 1–6; Salcedo-Martínez et al., 1988:83; Hoyle, 1994:93; 

González-González et al., 1996:216.

Gracilaria johnstonii Setchell et N. L. Gardner, 1924:752, pl. 22: figs. 11–14, 

pl. 60; Dawson, 1944a:293; González-González et al., 1996:213.

Gracilaria sinicola Setchell et N. L. Gardner, 1924:752, pl. 62; GonzálezGonzález et al., 1996:215.

Gracilaria vivipara Setchell et N. L. Gardner, 1924:750, pl. 24: figs. 28, 29, 

pl. 63; González-González et al., 1996:217.

Gracilaria textorii sensu [in part; for the following citations] Dawson, 

1959a:26; 1961a:211; Norris, 1973:13; Huerta-Múzquiz, 1978:338; 

Littler and Littler, 1981:151; Norris, 1985a:94, tbls. 1, 2; 1985b:132, 

fig. 1; 1985d:212; Huerta-Múzquiz and Mendoza-González, 1985:50; 

Mendoza-González and Mateo-Cid, 1985:30; Mateo-Cid et al., 

1993:48; González-González et al., 1996:216; Riosmena-Rodríguez 

et al., 1998:27; L. Aguilar-Rosas et al., 2000:130; Pacheco-Ruíz and 

Zertuche-González, 2002:467; Pacheco-Ruíz et al., 2008:207 [non 

Gracilaria textorii (Suringar) Hariot, 1891:223; basionym: Sphaerococcus textorii Suringar, 1868:259, pl. 23; J. Agardh, 1876:426].

Algae flabellate, of 1 to few irregularly subdichotomously 

branched, flat, broad blades, light rose red to darker red, tending 

to be coriaceous; up to 35 cm tall; branches (1.5–)2.0–5.0 cm 

wide; (350–)400–600(–750) μm thick in transection; attached 

below by a discoid holdfast. Blades branched in 1 plane, up 

to 6 times; margins usually smooth and entire, but some with 

simple, divided, or branched lateral proliferations; upper divided 

segments, narrower, up to 10 mm wide, with ultimate segments 

4–5 mm wide, terminating in rounded to attenuate apices. Medulla of large, thin-walled ovoid cells, 250–500 μm in width; 

outer medulla cells smaller, subglobose to oval, about 15–50(–

100) μm in diameter. Cortex usually a single layer of small pigmented cells, about 5 μm in diameter; cortex becoming 2 layers 

of cortical cells in larger, older portions.

Tetrasporangia ovate to elongate, 15–22 μm in diameter; 

borne in modified cortex, surrounded by anticlinally elongated 

cortical cells; scattered over surface. Carpogonial branches 

2-celled; in terminal portions of thallus. Cystocarps globose, 

large, 1200–1600 μm in diameter, prominent, ostiolate, slightly 

rostrate; scattered over thallus. Gonimoblast of pseudoparenchymatous cells, developed from a large fusion cell, with numerous traversing (absorbing) filaments to pericarp. Spermatangia in 

individual to confluent, cup-shaped cavities (Textorii-type) surrounded by modified cortical cells.

Habitat. On rocks; lowermost intertidal to shallow 

subtidal, down to 20 m depths.

Distribution. Gulf of California: San Felipe to 

Guaymas; Isla San Esteban (Islas de la Cintura); Bahía Concepcíon to Bahía de La Paz, including Isla Carmén, Isla Espíritu 

Santo, and La Paz.

Type Locality. La Paz, Baja California Sur, Gulf of 

California, Mexico.

Remarks. Gracilaria vivesii, a species originally described from the southern Gulf (Howe, 1911; Dawson, 1949a), 

is recognized in the field by its broad, flabellate, dichotomously 

divided frond, usually without lateral proliferations. Apparently 

only occasionally collected in the southern Gulf, G. vivesii is 

more frequently found in the subtidal of the northern Gulf of 

California and Islas de la Cintura. The rose red to dark red or 

greenish red divided blades of Gulf G. vivesii are very variable in 

size; this high degree of phenotypic variation makes it difficult to 

define the species limits.

Dawson (1949a, as G. vivesii) and Ohmi (1955) noted 

many Gulf specimens were similar to G. textorii from Japan. 

Ohmi (1955) observed G. vivesii to be coriaceous and G. textorii to be usually membranous, also noting G. vivesii to be 

less proliferous and less dissected than G. textorii, but then he 

concluded they were conspecific. Most of the Gulf of California specimens referred to “Gracilaria textorii” sensu Dawson 

(1961a) are, for now, referred to Gracilaria vivesii M. Howe 

(1911). Molecular analyses will help clarify the taxonomic 

status of Gulf of California G. vivesii and its relationship to 

Japanese G. textorii. Records of G. vivesii from tropical Pacific 

Mexico (Salcedo-Martínez et al., 1988) and Peru (Acleto O., 

1973, 1986; Ramírez and Santelices, 1991) should be reexamined to verify their identification.

Uncertain Record:

Gracilaria hancockii E. Y. Dawson

Gracilaria hancockii E. Y. Dawson, 1944a:297, pl. 65: fig. 2; 1949a:39; 

González-González et al., 1996:213; Pacheco-Ruíz et al., 2008:206.
NUMBER 96 • 395

FIGURE 199. Gracilaria vivesii: A. Habit (JN-5252, US Alg. Coll.-159675). B. Female gametophyte, with the largest cystocarps of the species 

of Gracilaria in the Gulf of California (JN-2966, US Alg. Coll.-159659). C. Habit of a large specimen (JN-6198, US Alg. Coll.-159683).
396 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Algae of several slender axes, cylindrical at base, 800–1200 

μm in diameter, becoming compressed to flattened above, up to 

2 mm wide; axes loosely, multifariously branched; apices acute, 

attenuated; attached directly to or by a very short stipe above a 

discoid holdfast. Medulla of large, thin-walled cells; cortex of 

2–3 layers of much smaller cells (after Dawson, 1944a).

Tetrasporangia not originally described (Dawson, 1944a); tetrasporophytes were later noted to be either a species of Gracilaria

or Gracilariopsis (Dawson, 1949a). Cystocarps as originally 

described (Dawson, 1944a) were later found to be a species of 

Agardhiella (see Dawson, 1949a). Spermatangia not known.

Habitat. Known only from dredged material; subtidal.

Distribution. Gulf of California. Islas de la Cintura: off “South Shore Beach,” Puerto Refugio, Isla Ángel de la 

Guarda; southern end of Isla Tiburón.

Type Locality. Dredged 4–32 m depths; off southern shore of Isla Tiburón near Isla Turner (Turners) (Islas de la 

Cintura), Gulf of California, Mexico.

Remarks. Dawson’s (1949a:39) reexamination of the 

type collection of Gracilaria hancockii (Dawson, 1944a: pl. 65: 

fig. 2; AHFH, now UC) found it to contain at least three mixed 

elements: (1) sterile Gracilaria subsecundata, (2) tetrasporophytic 

specimens of either a Gracilaria or a Gracilariopsis, and (3) cystocarpic material of a species of Agardhiella. At the time, Dawson 

(1949a) considered G. hancockii a “nomen confusum.” Since the 

newer Botanical Codes (e.g., McNeill et al., 2006, 2012) no longer 

recognize “nomen confusum,” G. hancockii could be based on the 

selection of the sterile specimen that Dawson (1949a) referred to

G. subsecundata. This would make G. hancockii conspecific with 

G. subsecundata until molecular analyses can be done on the type 

material to further elucidate its taxonomic status.

Uncertain Record:

Gracilaria textorii (Suringar) Hariot

Sphaerococcus textorii Suringar, 1868:259, pl. 23; 1870:135; J. Agardh, 

1876:426. 

Gracilaria textorii (Suringar) Hariot, 1891:223.

Gracilaria textorii (Suringar) De Toni, 1895:27, nom. illeg.; [remaining citations in part only, excluding Gulf of California Gracilaria vivesii:] Ohmi, 

1955:320, pls. 1–6; 1958:40, figs. 20, 21; Dawson, 1959a:26; Dawson et 

al., 1960b:21; Dawson, 1961a:211; Yamamoto, 1978:123, pls. 12–14, 

pl. 42: figs. 5–7, pl. 43: figs. 1–4; González-González et al., 1996:216; 

M.-S. Kim et al., 2010:394, 395, figs. 13–20.

Remarks. The presence of the Japanese Gracilaria 

textorii in the northern Gulf of California seems unlikely and requires further study. Most of the specimens of Gulf “G. textorii

sensu Dawson (1961a)” are referred to G. vivesii. Although the 

two species were proposed to be conspecific by Ohmi (1955), a 

conclusion that was later followed by Dawson (1961a), Yamamoto (1978), and most others since then, their relationship remains to be tested. The two are suggested herein to be separate 

species. There is also the possibility that Japanese G. textorii has 

been introduced in the Gulf of California, but if so, it is not easily 

recognized, and comparative molecular analyses will be necessary 

to elucidate its presence and relationship to the Gulf of California 

G. vivesii. For now, Gracilaria textorii (Suringar) Hariot (1891; 

type locality: Okinawa Prefecture, west coast of Hokkaido, Sea of 

Japan) is recognized as a western Pacific species from Japan (Inagaki, 1933; Ohmi, 1958; Yamamoto, 1978; Yoshida, 1998; M.-

S. Kim et al., 2010), China (Xia and Yamamoto, 1985), Korea 

(M.-S. Kim et al., 2006), and Vietnam (Nguyên, 1992).

In a molecular systematic study, M.-S. Kim et al. (2006) 

found western Pacific G. textorii from Korea and Japan to be 

identical and both to be genetically distinct from Gracilaria incurvata Okamura (1931:41, pl. 73: figs. 1–6). They also noted 

that Japanese “G. textorii” sensu Gurgel and Fredericq (2004, 

GenBank accession number AY049325, from Gobogahana, 

Japan) was molecularly the same as the Japanese G. incurvata.

Some forms of G. textorii and G. incurvata can be confused. 

Gracilaria incurvata is a species characterized by narrower 

blades, 0.5– 1.5 cm wide, 3–5 medullary cell layers, a fleshy 

texture, and incurved upper portions (Yamamoto, 1978, 1985; 

M.-S. Kim et al., 2006). Smaller, narrower Gulf of California 

forms that were referred to “G. textorii” (sensu Dawson, 1961a) 

need to be critically compared, morphologically and genetically, to 

the Japanese G. incurvata Okamura, southern California G. cunninghamii, southern Gulf of California G. vivesii, and Japanese G. 

textorii to resolve the taxonomic status of Gulf material.

Gracilaria textorii has also been reported in Pacific Mexico 

on the west coast of Baja California Sur from Bahía Tortugas 

(inside southeast Bahía San Bartolomé) to Punta Pequeña (north 

of Bahía San Juanico) and the Chester Islets (NE of Punta Falsa) 

(Dawson, 1961a), and the Galápagos Islands (Taylor, 1945, as 

“G. johnstonii”). Dreckmann (2002) observed that the Pacific 

Mexico “G. textorii” from Islas Revillagigedo (Taylor, 1945), 

Colima (Mateo-Cid and Mendoza-González, 1991), and Guerrero (Salcedo-Martínez et al., 1988) differed from the original 

description as well as from those of the Gulf of California. These 

collections should also be reexamined and compared with material of Gulf G. vivesii and Japanese G. textorii.

Excluded Species:

Gracilaria verrucosa

Gracilaria verrucosa (only Gulf of California collections) sensu Dawson, 

1961a:214, pl. 20; 1961b:43: 1966a:22; Norris, 1973:13; HuertaMúzquiz and Mendoza-González, 1985:50; Norris, 1985c:133; 

Mendoza-González and Mateo-Cid, 1986:424; González-González, 

1996:315; Riosmena-Rodríguez et al., 1998:27 [non Gracilaria verrucosa (Hudson) Papenfuss, 1950:195, nom. rej., basionym: Fucus verrucosus Hudson, 1762:470, nom. rej.; see Irvine and Steentoft, 1995; 

this taxon is now Gracilariopsis longissima (Gmelin) Steentoft, L. Irvine et W. Farnham, 1995:117, basionym: Fucus longissimus Gmelin, 

1768:134].

Remarks. All Gulf of California specimens identified as “Gracilaria verrucosa” need to be reexamined and, once 

identified to genus, compared to the narrow, cylindrical species of Gracilaria (G. pacifica, G. papenfussii, and G. vermiculophylla) and Gracilariopsis (G. andersonii, G. animasensis, 
NUMBER 96 • 397

G. megaspora, and G. rhodotricha) that are known or reported 

in the Gulf of California.

Gracilariopsis E. Y. Dawson

Gracilariopsis E. Y. Dawson, 1949a:40; Fredericq and Hommersand, 

1989b:228–241. 

Algae are erect and exhibit varying degrees of branching, with 

most species being cylindrical, elongated, and often stringy, but a 

few are flattened. All are attached by a small discoid holdfast. 

Tetrasporophytes are as for the family. Carpogonial branches 

and development of the primary fusion cell are also as for the 

family. The mature fusion cell is composed of the carpogonium 

and up to six adjacent sterile cells. Anatomically, the cystocarps 

of Gracilariopsis notably lack traversing (absorbing) filaments 

that in Gracilaria connect the gonimoblast to the pericarp. Instead, the cystocarp has a broad-based gonimoblast of small 

cells linked to the basal cells of the carposporophyte by specially 

modified cells on the cystocarp cavity floor by secondary pit connections through gonimoblast conjunctor cells. Carposporangia 

are formed in chains at the periphery of the gonimoblast cells. 

Spermatangial parent cells are in pairs or threes on the outer 

cortical cells, with each cutting off a single spermatangium by a 

transverse division. Spermatangia are superficial and may cover 

the thallus surface or are in sori flush with outer cortical cells 

(Chorda-type; Yamamoto, 1978). 

Remarks. Species of Gracilariopsis are generally 

cylindrical and considered less diverse in habit than those of 

Gracilaria (Gurgel and Fredericq, 2004). The first flat species 

of Gracilariopsis was recognized and described by Gurgel et al. 

(2003a). 

Without male or female gametophytes, or molecular evidence, the genera and species of Gracilariopsis and Gracilaria

with similar habits can be difficult to distinguish. The two genera are separated primarily by characteristics of the sexual reproductive structures. In describing Gracilariopsis, Dawson 

(1949a) included species that lacked traversing (absorbing) 

filaments between the gonimoblast and the pericarp. Fredericq 

and Hommersand (1989a, 1989b, 1990) emphasized four differences between the two genera: (1) fusion cells in Gracilariopsis incorporate only the cells closely flanking the carpogonium 

compared to Gracilaria, where additional cells are later added; 

(2) traversing filaments (absorbing filaments or nutrient tubular 

cells) between the gonimoblast and pericarp within the cystocarp 

are present in Gracilaria but absent in Gracilariopsis; (3) the carposporangial chains of Gracilariopsis are straighter and more 

regularly organized; (4) spermatangial parent cells develop from 

superficial (surface) cortical cells in Gracilariopsis, whereas in 

Gracilaria they are developed from adventitious filaments arising 

on subsurface (intercalary) cortical cells, forming depressions, 

cavities, or deep pits.

One species, Gracilariopsis longissima (S. G. Gmelin) Steentoft, L. M. Irvine et Farnham (1995), is reported in the southern 

Gulf from Bahía de Navachiste, Sinaloa (Orduña-Rojas et al., 

2008). Three cylindrical species of Gracilariopsis, including one 

new species, are recorded in the northern Gulf of California.

KEY TO THE SPECIES OF GRACILARIOPSIS IN THE NORTHERN GULF OF CALIFORNIA

1a. Branches slender, less than 500 μm in diameter; thalli up to 20 cm long; cystocarps smaller, about 500 μm in diameter; 

carposporangia larger, about 50 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. megaspora

1b. Branches broader, mostly 0.6–1.5 mm (or more) in diameter; thalli usually longer, more than 20 cm long (sometimes very 

long to 1.0 m or more); carposporangia 15–35 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Thalli mostly very long, up to 1.2 m; main axes 0.5–1.5 mm in diameter; lateral branches narrow, 300–600 μm in diameter, generally shorter; cystocarps 0.8–1.6 mm in diameter; carposporangia 20–30 μm in diameter . . . . . G. animasensis

2b. Thalli usually shorter, mostly up to 20 cm; main axes 1.5–3.5 mm in diameter; lateral branches usually broader, 0.5–1.5 

mm in diameter, usually longer; cystocarps mostly over 1 mm diameter; carposporangia about 28 μm in diameter . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. andersonii

Gracilariopsis andersonii (Grunow) E. Y. Dawson

Cordylecladia andersonii Grunow in Piccone, 1886:62 [in part].

Gracilariopsis andersonii (Grunow) E. Y. Dawson, 1949a:43, pl. 16: figs. 

1–4; 1961a:216, pl. 10: fig. 16, pl. 11: fig. 13, pl. 19: fig. 2; 1961b:430; 

González-González et al., 1996:217; Gurgel et al., 2003a:64, 66, fig. 

37, tbls. 1, 2; Gurgel et al., 2003b:154, 161, figs. 2, 3b, tbl. 1; Gurgel 

and Fredericq, 2004:139, 148, fig. 1, tbl. 1. 

Gracilaria sjoestedtii Kylin, 1930:55, figs. 40E,F, 41, 43; Smith, 1944:267, pl. 

63: fig. 4; Dawson, 1944a:296; Norris, 1973:12 [in part]; Abbott and 

Hollenberg, 1976:498,fig. 443; Silva, 1979:322 [in part]; R. AguilarRosas, 1982:84; Sánchez-Rodríguez et al., 1989:43; Fernández-García 

et al., 2011:62.

Gracilariopsis sjoestedtii (Kylin) E. Y. Dawson, 1949a:40 [in part], pl. 15: 

fig. 10, pl. 16: figs. 5–8, pl. 17: figs. 1–9, pl. 18: fig. 4; Dawson and Beaudette, 1959:15; Dawson, 1961a:218 [in part], pl. 10: fig. 14, pl. 11: 

fig. 10, pl. 23: figs. 1–6; 1961b:430; Hollenberg and Abbott, 1966:86; 

Dawson, 1966a:22; Huerta-Múzquiz and Tirado-Lizárraga, 1970:128; 

Fernández-García et al., 2011:62.

Gracilaria lemaneiformis sensu Abbott, 1983:561, fig. 4 [left specimen only]; 

Abbott, 1985a:97; R. Aguilar-Rosas and Aguilar-Rosas, 1994:522; 

Mendoza-González and Mateo-Cid, 1996b:66, pl. 5: figs. 16, 17; 

Pacheco-Ruíz et al., 1999:509; L. Aguilar-Rosas et al., 2000:130; 

L. Aguilar-Rosas et al., 2002:234; Pacheco-Ruíz et al., 2008:207; PérezEstrada et al., 2012:191 [non Gracilaria lemaneiformis (Bory de Saint 
398 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Vincent) Greville, 1830:liv; Gracilaria lemaneiformis (Bory de Saint 

Vincent) Weber-van Bosse, 1928:435, now =Gracilariopsis lemaneiformis (Bory de Saint-Vincent) E. Y. Dawson, Acleto O., et Foldvik, 

1964:59, and restricted in distribution to Pacific South America; see 

Gurgel et al., 2003a:64, 66].

Algae erect, in the northern Gulf mostly 15–18 cm long (but 

also reported up to 1 m, as “G. sjoestedii”); of few to several, 

cylindrical axes, 1.5–3.5 mm in diameter; sparingly to abundantly, irregularly branched; arising from stoloniferous prostrate 

branches and a discoid holdfast. Branches narrower than axes, 

mostly 0.5–1.0 mm in diameter. Medulla of large cells, grading 

into cortex of 3–4 layers of small, pigmented, cortical cells.

Tetrasporangia oblong, 30–38 μm long, embedded in modified cortex of anticlinally elongated cells; borne in the upper 

branches. Cystocarps protruding, globose to dome shaped, 800–

1800 μm in diameter; scattered over branch surfaces; carposporangia to about 28 μm in diameter, borne in chains. Gonimoblast 

of small cells, broad based; lacking traversing (absorbing) 

filaments between pericarp and gonimoblast. Spermatangia in 

superficial layer (Chorda-type) arising from the cortex and covering branch surface.

Habitat. Growing on rocks, sometimes partially 

sand covered or in fine sediment; intertidal to shallow subtidal, 

down to 2 m depths.

Distribution. Gulf of California: El Tornillal 

(Gulfo de Santa Clara); Bahía La Choya (Bahía Cholla, vicinity 

of Puerto Peñasco) to Guaymas; San Felipe; Bahía Topolobampo 

(with query). Eastern Pacific: British Columbia to California; 

Punta Descanso (Baja California) to Bahía Magdalena (Baja California Sur); Oaxaca to Chiapas; El Salvador; Costa Rica.

Type Locality. Santa Cruz, Santa Cruz County, 

California, USA (Gurgel et al., 2003b).

Remarks. Northern Gulf of California specimens 

morphologically similar to the northeastern Pacific Gracilariopsis 

andersonii are tentatively referred to this species. Molecular systematic studies on northern Gulf G. andersonii are needed to test 

its taxonomic identity in comparison with the California G. andersonii from its type locality. Specimens identified as “Gracilariopsis sjoestedii” sensu Dawson (1961a) from Ensenada de San 

Francisco are Gracilariopsis animasensis. Other northern Gulf 

specimens referred to “Gracilaria lemaneiformis” (cited above)

and to “Gracilaria sjoestedii” from Punta Cheuca and Guaymas 

(Mendoza-González and Mateo Cid, 1985) and Laguna Agibampo, Sonora and Sinaloa (Ortega et al., 1987), should also be 

reexamined to determine if they too belong here or are another 

cylindrical species.

Gracilariopsis animasensis Gurgel et J. N. Norris, sp. nov.

FIGURES 200–202

“Gracilariopsis sp. 1” sensu Gurgel et al., 2003a:59–60, 64–66, tbl. 1; 

2003b:154, figs. 1, 2, tbl. 1 [as “Gracilariopsis lemaneiformis Mexico” 

and “G. lemaneiformis Australia”]; Gurgel and Fredericq, 2004: fig. 1, 

tbl. 1 [as “Gracilariopsis sp. Australia”].

Cordylecladia lemaneiformis sensu Setchell and Gardner, 1924:759 [non 

Cordylecladia lemaneiformis (Bory de Saint-Vincent) M. Howe, 

1914:128, which is now Gracilariopsis lemaneiformis (Bory de SaintVincent) E. Y. Dawson, Acleto O. et Foldvik, 1964:59].

Gracilaria lemaneiformis sensu Dawson, 1961a:415 [in part], pl. 23: figs. 

1–6; 1966a:22; Norris, 1985a:93, tbls. 1, 2, fig. 33; Norris, 1985b:125, 

figs. 9, 10 [non Gracilaria lemaneiformis (Bory de Saint-Vincent) 

Weber-van Bosse, 1928:151, 435].

Gracilariopsis lemaneiformis sensu Womersley, 1996:30, fig. 8A–F; 

Arellano-Carbajal et al., 1999:51; Pacheco-Ruíz and ZertucheGonzález, 2002:467 [non Gracilariopsis lemaneiformis (Bory 

de Saint-Vincent) E. Y. Dawson, Acleto O., et Foldvik, 1964:59; 

basionym: Gigartina lemaneiformis Bory de Saint-Vincent, 

1828:151].

Gracilariopsis sjoestedii sensu Dawson, 1949a:42, and Dawson, 1961b:218 

[both in part; only the Ensenada de San Francisco specimens]; Norris, 

1973:12, and Huerta-Múzquiz, 1978:337 [both in part; only Bahía de 

Las Ánimas specimens; non Gracilariopsis sjoestedii (Kylin) E. Y. Dawson, 1949a:40, basionym: Gracilaria sjoestedii Kylin, 1930:55, which is 

now Gracilariopsis andersonii (Grunow) E. Y. Dawson, 1949a:43; see 

Gurgel et al., 2003b:154].

Latin Description. Algae graciles, omnino ramis 

paucis ad pluribus longis teretibus, ad 1.2 m longae, e hapterono 

discoideo plerumque ramulis prostratis consociato orientes; axes 

principales conspicui, (0.5–)0.7–1.5 mm diametro, ubique irregulariter ramosi, parci ad abundantes, ramis brevibus, plerumque 

gracilioribus; rami laterales 300–600 μm diametro; ramuli ultimi 

150–200 μm diametro, acuminati sed saepe effracti. Medulla 

stratis 3–5 cellularum; cellulis magnis, 200–500 μm diametro. 

FIGURE 200. (Opposite) Gracilariopsis animasensis Gurgel et J. N. Norris, sp. nov.: A. Holotype (JN-3215 ♀; US Alg. Coll.-89276). B. Cystocarpic specimen from Ensenada San Francisco, Gulf of California (EYD-1813, AD-A6283). C. Transection though middle part of the main 

axis detailing the gradual transition between medulla and cortex and radially elongated cortical cells (EYD-1813, AD-A6283, microscope slide 

21062). D. Longitudinal section through cystocarp; note the absence of traversing filaments and the presence of elongated cells that connect the 

gonimoblast to cells on the floor of the carposporophyte, with the irregular shape of the gonimoblast mass containing well-defined, large gonimoblast cells in the middle, well-defined pericarp composed of small, laterally compressed cells, and carposporangia organized in short chains 

(EYD-1813, AD-A6283, microscope slide 21061). (For C and D, note that Gulf of California specimens collected in 1946 did not expand when 

immersed in water, hence the compressed aspect of the sections).
NUMBER 96 • 399
400 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 201. Gracilariopsis animasensis from South Australia: A. Cystocarpic specimen. B. Nonreproductive specimen (A, B, from Lake Butler, Robe, AD-A64282c). C. Transection of thallus showing vegetative structure (AD-A63430, microscope slide 14314).
NUMBER 96 • 401

Tetrasporangia decussate divisa, ovoidea ad ellipsoidalia, 38–55 

μm longa, 15–35 μm diametro. Cellulae corticales radiatim 

elongatae. Carposporophytum base lata, cellula conjunctionum 

persistenti sed parva, sine filamentis peragrantibus (bibulis) 

pericarpium ad gonimoblastum jungentibus. Cellulae inferae 

gomnioblasti ovoideae (non ampliatae), 20–40 μm diametro, 

foveis ad cellulas soli cystocarpi extense conjungentes. Cellulae 

carposporophytum ad solum cystocarpi conjungentes elongatae, 

conspicuae. Gonimoblastus cellulis majoribus distinctis consistens, irregulariter formatus. Spermatangia in strato superficiali 

(ut in Chorda).

Algae slender, of a few to several long, cylindrical branches 

throughout, up to 1.2 m long; arising from a discoid holdfast 

usually associated with prostrate branches. Main axes conspicuous (Figures 200A,B, 201A,B), (0.5–)0.7–1.5 mm in diameter, 

branched irregularly, sparingly to abundantly, along their entire 

FIGURE 202. Gracilariopsis animasensis from South Australia: A. Transection through middle part of main axis showing gradual transition 

between medulla and cortex and radially elongated cortical cells (AD-A63430, microscope slide 14316). B. Longitudinal section through a cystocarp depicting the absence of traversing nutritive filaments, well-formed medullary cell layer at the base of the carposporophyte, and irregular 

shape of the gonimoblast mass, which contains well-defined, large gonimoblast cells in the middle and a well-defined pericarp composed of small 

laterally compressed cells. C. Detail of elongated cells connecting gonimoblast cells and gametophyte cells at the base of the cystocarp (arrow); 

note the well-developed layers of medullary cells at the base of the carposporophyte (B, C, AD-A63430, microscope slide 14317). D. Transection through middle of a tetrasporophyte showing decussate-cruciately divided tetrasporangia (arrow) flanked by slightly modified cortical cells 

(AD-A63430, microscope slide 14320). E. Transection through the middle part of a male gametophyte showing Chorda-type spermatangia and 

spermatium cut off from cortical spermatangial parent cell (arrow) (AD-A63430, microscope slide 14319).
402 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

length, with short, usually more slender, lateral branches, 300–

600 μm in diameter; ultimate branchlets 150–200 μm in diameter, acuminate but commonly broken. Medulla of 3–5 cell layers; 

of large colorless cells, 200–500 μm in diameter, with numerous 

secondary pit connections and thick cell walls, 10–20 μm; cells 

becoming progressively smaller outward and grading into subcortex of 3–5 cells; outer cortex, 1–2(–4) cell layers of small, radially elongated (subpalisade), pigmented cortical cells; cortical cells 

sometimes ovoid to more or less isodiametric (in both transverse 

and longitudinal sections), 6.0–17.5 μm long, 4–7 μm in diameter 

(Figures 200C, 201C, 202A); diagonal cortical cell division evident. Cortex often with intact hairs above conspicuous basal cells.

Tetrasporangia decussately divided, ovoid to ellipsoidal, 

38–55 μm long, 15–35 μm in diameter; within slightly modified cortex of anticlinally elongated cells (Figure 202D); pit connected to inner cortical cells; scattered throughout the cortex 

of branches. Cystocarps protruding, hemispherical to conical, 

usually dome shaped, with a broad base or sometimes slightly 

constricted at base; 1.0–1.6 mm in basal diameter, 800–1600 μm 

in height; with or without beaked rostrum; irregularly scattered 

over branch surfaces, primarily occurring on main axes and 

thicker branches, rarely on thin terminal branchlets. Pericarp 

100–200 μm thick, of 8–14 small, isodiametric cells with secondary lateral pit connections, all compacted and well organized in 

files (Figures 200D, 202B). Carposporophyte broad based, with 

a persistent but inconspicuous fusion cell and without traversing (absorbing) filaments connecting the pericarp to the gonimoblast. Gonimoblast of well-defined larger cells, irregular in 

shape; lower cells of gonimoblast, ovoid (not enlarged), 20–40 

μm in diameter, extensively pit connected to cells of the cystocarp floor (Figures 202B–C). Cells connecting carposporophyte 

to the floor of the cystocarp, elongated and conspicuous (Figures 

200D, 202B–C). Carposporangia more or less ovoid, 20–30 μm 

in diameter; developed in chains, usually unbranched or occasionally branched. Spermatangia in superficial layer (Chordatype) arising from the cortex and covering branch surface; cut 

off from elongated initials by transverse walls; spermatia 2–3 

mm in diameter (Figure 202E).

Etymology. The name of the type locality, Bahía de 

Las Ánimas (“bay of lost souls”), is based on ánima (Spanish, 

feminine noun), which means soul. We name this species G. animasensis not only for its type locality, one of the locales where 

we obtained specimens, but also to loosely reflect the meaning 

of a “lost soul” of Gracilariopsis since initially it was unclear 

whether the species was native or exotic (non-indigenous).

Holotype. Coll. J. N. Norris and K. E. Bucher, JN3215 (cystocarpic), 23 May 1972, US Alg. Coll.-089276 (Figure 

200A).

Isotypes. US Alg. Coll.-89274, US Alg. Coll.-156378 

(Norris, 1985b: fig. 9), and US Alg. Coll.-159743.

Type Locality. Growing in fine–sediment sand, 

intertidal to 1.0 m depths; in shallow channel near entrance 

to mangrove estero, inside Bahía de Las Ánimas (28°48′28′′N, 

113°21′39′′W), east coast of Baja California, Gulf of California, 

Mexico.

Paratypes. Gulf of California, Mexico: Bahía de 

Las Ánimas, Baja California, from aquaculture tanks, Coll. 

J .A. Zertuche-González, June 1998 (rbcL GenBank accession 

number AY049416 [C.F.D. Gurgel-211], specimen in silica gel). 

Ensenada de San Francisco (~7 km east of Bahía San Carlos and 

~15.7 km NW of Heroica Guaymas), Sonora: Coll. E. Y. Dawson (EYD-1813 [♀], 17 May 1946, AD-A6283 (Figure 200B–D), 

including microscope slides 21061 and 21062 [Figure 200B–D], 

and EYD-1813 [♀, ♂, and tetrasporophyte], AHFH, now UC, 

and EYD-1814, AD-A6262).

South Australia, Australia: Lake Butler (small lake 

used as harbor for fishing fleet; Womersley, 1996:31), Robe 

(37°9′47.61′′S, 139°45′4.83′′E], Coll. H. B. S. Womersley, 15 

April 1994: AD-A63430a (3 specimens; Figures 201C, 202B,C), 

AD-A63430b (2 specimens), AD-A64745, AD-A64775, and 

AD-A64404; 3 March 1995: AD-A64282a (3 specimens; ♀ on 

left side), AD-A64282b (2 specimens; Figure 201A–B), and ADA64282c (2 specimens; Figure 201A); and 1 December 2007: 

AD-A47259, AD-A47260, and AD-A74304a-h (9 specimens on 

8 herbarium sheets, all nonreproductive). Middle Beach (mangrove area), north of metropolitan Adelaide: Coll. C. F. D. Gurgel, AD-A89218 and AD-A89219.

Habitat. Mostly growing in fine–sediment sand 

and on small, sand-covered rocks, pebbles, and shells in shallow, protected waters of esteros, estuaries, marinas, lagoons, and 

bays; intertidal to very shallow subtidal, 0–3 m depths (habitats 

are similar in both the northern Gulf of California and South 

Australia).

Distribution. Gulf of California: Bahía de Los 

Ángeles, Baja California, to Punta Trinidad, Baja California 

Sur; Ensenada de San Francisco (between Bahía San Carlos and 

Guaymas), Sonora. Southern Ocean: Lake Butler, Robe, and 

Middle Beach mangrove area, north of metropolitan Adelaide, 

both South Australia, Australia.

Remarks. Gracilariopsis animasensis has a wide, 

disjunct distribution, known only from the northern Gulf of 

California and two locales in South Australia. Northern Gulf of 

California specimens collected by E. Y. Dawson on 17 May 1946 

(Dawson, 1949a, as “Gracilariopsis sjoestedii”; EYD-1813 [♀], 

AD-A6283, and EYD-1814 [♀, tetrasporic], AD-6262, and 

AHFH, now UC) from the Sonoran coast at Ensenada de San 

Francisco (NW of Guaymas) are now identified to be Gracilariopsis animasensis. Specimens of G. animasensis have been found 

growing attached from the Baja California coast of the northern 

Gulf since 1969 in the intertidal of the estero (small lagoon into 

which the tide flows) at Bahía de Las Ánimas (JN-387, MLML; 

Norris, 1973, as “G. sjoestedii”; 1985b, as “G. lemaneiformis”) 

and on intertidal, sand-covered rocks at Bahía San Francisquito 

(JN-277, US Alg. Coll.-090173). In South Australia it was first 

collected by H. B. S. Womersley in 1994 from Lake Butler, Robe 

(Womersley, 1996, as “Gracilariopsis lemaneiformis”), indicating it to be an introduced species. 

Sequence analysis of the rbcL gene of northern Gulf specimens from Bahía de Las Ánimas revealed them to be an undescribed species of Gracilariopsis (Gurgel et al., 2003a, as 
NUMBER 96 • 403

“Gracilariopsis sp. 1”). The Gulf of California Gracilariopsis 

animasensis can be superficially similar to some larger specimens 

of the northeastern Pacific Gracilariopsis andersonii (Grunow) 

E. Y. Dawson and to the Pacific South American Gracilariopsis 

lemaneiformis (Bory de Saint Vincent) E. Y. Dawson, Acleto O. 

et Foldvik (1964) from Peru to Chile (Gurgel et al., 2003b). The 

latter two species are typically more slender and have fewer, but 

usually longer, lateral branches, whereas Gracilariopsis animasensis is generally larger, more robust and succulent, and heavier, 

often with more abundant, but shorter, lateral branches.

The works of José A. Zertuche-González and Isaí PachecoRuíz and their collaborators (e.g., Arellano-Carbajal et al., 

1999; Pacheco-Ruíz et al., 1999, 2003) have described important aspects of the biology and ecology of this species in the 

Gulf of California. Pacheco-Ruíz et al. (1999, as “Gracilariopsis lemaneiformis”) studied seasonal variation in biomass of 

G. animasensis along the Baja California coast of the northern Gulf. Agar from G. animasensis was reported to be of high 

quality, and since 1995, it has been exploited commercially in 

the Gulf of California from Bahía de Los Ángeles (east coast of 

Baja California) to Punta Trinidad (east coast of Baja California 

Sur), with an estimated 46,000 dry tons available for harvest 

(Pacheco-Ruíz et al., 2003). Biomass production is reportedly 

massive, and individual alga growth rates up to 12% per day 

have been observed, peaking when the water temperatures and 

the nutrient concentrations are highest (spring and summer in 

the northern Gulf of California (Pacheco-Ruíz et al., 1999, as 

“G. lemaneiformis).” In South Australia, Lake Butler is situated 

in an upwelling region where during the spring-summer season, 

temperatures are the lowest while light and nutrient concentration are the highest, quite similar to the best growing photoperiod conditions of Gracilariopsis animasensis as described for 

the Gulf of California populations.

Gracilariopsis megaspora E. Y. Dawson

Gracilariopsis megaspora E. Y. Dawson, 1949a:45, pl.18: figs.1–3; 

1961a:217, pl. 11: fig. 3, pl. 22: fig. 2; 1961b:430; González-González 

et al., 1996:217; Gurgel et al., 2003a:61, tbl. 2.

Gracilaria megaspora (E. Y. Dawson) Papenfuss, 1967:100; Chang and 

Xia, 1976:145, figs. 40, 41; Norris, 1985b:127; Abbott, 1995:191; 

González-González et al., 1996:214; Xia and Zhang, 1999:60, fig. 36, 

pl. 5: fig. 6; Pacheco-Ruíz et al., 2008:206.

Algae cylindrical, up to 20 cm long, thin, less than 500 μm 

in diameter throughout; main axes abundantly branched to 2–3 

orders; branches 5.0–35 mm long; attached by a small discoid 

holdfast. Medulla of large cells, up to 100 μm wide, with an 

abrupt change to subcortex of 2–3 layers of subcortical cells 

20–35 μm in diameter; outer cortex of 1 layer of anticlinally 

arranged pigmented cells, about 10 μm in diameter, often with 

abundant short hairs above their basal cells.

Tetrasporangia unknown. Cystocarps projecting, globose, 

about 500 μm in diameter, slightly constricted at their base and 

barely rostrate. Gonimoblast of small, densely massed cells, rich 

in protoplasm, arising from a distinct fusion cell; lacking any 

nutritive filaments. Carposporangia in chains, ovoid, unusually 

large, to 50 μm long; each with a distinct central stellate body. 

Spermatangia unknown.

Habitat. Floating in shallow, sandy lagoon and 

probably attached to sand-covered rocks in shallows bays and 

lagoons; intertidal.

Distribution. Gulf of California: Bahía San Carlos. Western Pacific: China.

Type Locality. Lagoon, Bahía San Carlos (north of 

Guaymas), Sonora, Gulf of California, Mexico.

Remarks. In the Gulf of California, Gracilariopsis 

megaspora is only known from the type collection, a small, not 

very informative specimen. It has since also been reported in 

China (Chang and Xia, 1976; Xia, 1985; Xia and Zhang, 1999) 

and in India (Umamaheswara Rao, 1974; Silva et al., 1996a). 

It differs from Gracilariopsis andersonii and G. animasensis

in generally having thinner axes, with abundant, short, stubby 

basal hairs in the cortex and smaller cystocarps with very large 

carpospores. The described cystocarps of G. megaspora support 

its placement in Gracilariopsis. Future Gulf collections, particularly from the type locality, should reveal tetrasporangial and 

spermatangial specimens necessary to elucidate this species. Additional cystocarpic material will allow genetic testing to determine its relationship to other terete Gulf species.

Uncertain Record:

Gracilariopsis rhodotricha E. Y. Dawson

Gracilariopsis rhodotricha E. Y. Dawson, 1949a:47, pl. 19, figs. 3–7; 

1961a:317, pl. 10: fig. 9, pl. 11: figs. 11–12, pl. 21: fig. 1(holotype); 

1961b:430; González-González et al., 1996:217.

Gracilaria rhodotricha (E. Y. Dawson) Papenfuss, 1967:100.

Distribution. Eastern Pacific: Isla Clarión and Isla 

Socorro, Islas Revillagigedo (Dawson, 1949a; Serviere-Zaragoza 

et al., 2007).

Type Locality. Dredged from 56–102 m; off Isla 

Clarión, Islas Revillagigedo, Colima, Pacific Mexico.

Remarks. One specimen from Bahía de San Lucas, 

Baja California Sur (E. Y. Dawson-6847; US Alg. Coll.) was tentatively referred to G. rhodotricha (Norris, 1985c:133, fig. 12). 

Further collections and the finding of gametophytes of G. rhodotricha in the Gulf of California are needed to verify its presence. 

Additional type locality collections are needed for molecular testing of its generic and taxonomic status. Terada and Yamamoto 

(2002) referred the Japanese “G.rhodotricha” of Ohmi (1958) 

to Gracilaria vermiculophylla. Other records of G. rhodotricha

from Vietnam (Phạm-Hoàng, 1969) and Queensland (Lewis, 

1984) should also be reexamined.

Gracilariophila Setchell et H. L. Wilson

Gracilariophila Setchell et H. L. Wilson in Wilson, 1910:81; Fredericq et al., 

1989:167, figs. 1–36; Gerung and Yamamoto, 2002:209.

Algae are minute, colorless to whitish (lacks pigments, 

including chlorophyll), and more or less globose to postulate. 

They grow as adelphoparasites on some species of Gracilaria 

and Gracilariopsis on the host’s surface, with elongated rhizoidal 
404 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

filaments (cellular processes) that penetrate into its host’s tissue. 

The medulla is composed of large, thick-walled, somewhat angular cells that grade into the cortex of small cells.

Tetrasporangia are isolated, embedded in the cortex, and 

scattered over the thallus. Cystocarps are ostiolate and either 

embedded within the thallus or borne on the tuberculate surface. 

Spermatangia are superficial on the outer cortex.

One species of Gracilariophila is known from the northern 

Gulf of California.

Gracilariophila gardneri Setchell

Gracilariophila gardneri Setchell, 1923:393; Dawson, 1949a:51, pl. 23: 

figs. 4–7; 1961a:218; 1961b:430; 1966a:22; Abbott and Hollenberg, 

1976:500, fig. 448; Abbott, 1983:562; Norris, 1985b:125; GonzálezGonzález et al., 1996:217.

Algae a minute, more or less wart-like pustule, 3.0–3.5 mm 

in diameter; an adelphoparasite appearing whitish to yellowish on 

host species of Gracilaria and Gracilariopsis. Cellular processes 

penetrate host’s tissue and grow endophytically, often surrounding 

or isolating algal host cells and forming connections with them.

Tetrasporangia elongate to elliptical, 28–34 μm long, irregularly cruciately to partially zonately divided (see Dawson, 1949a: 

pl. 23: fig. 5); borne over pustule surface. Cystocarps hemispherical, nonrostrate, obscurely ostiolate, either isolated or grouped; 

carposporangia 11–13 μm in diameter. Spermatangia superficial, 

in outer tissue (up to 50 μm thick) of densely packed slender, 

anticlinal filaments, 6–17 μm long by 1.5–2.5 μm in diameter; 

spermatia about 3 μm in diameter.

Habitat. Found parasitic on Gracilaria crispata; on 

rocks and tidal platform; mid intertidal.

Distribution. Gulf of California: Playa Las Conchas (Playa Estacíon), Puerto Peñasco; Bahía Bocochibampo. 

Eastern Pacific: Santa Monica to La Jolla, southern California.

Type Locality. On Gracilaria cunninghamii Farlow ex J. Agardh; Santa Monica, Los Angeles County, southern 

California, USA.

Remarks. Gracilariophila gardneri can sometimes 

be found on Gracilaria crispata growing on the tidal platform, 

Playa Las Conchas, Puerto Peñasco (Dawson, 1966a; JN-3163, 

US Alg. Coll.), in the upper Gulf and in the southeast Gulf from 

Bahía Bocochibampo (Dawson, 1949a, 1961a). Dawson (1961a) 

noted Gracilariophila-like tubercles on Gulf “Gracilaria textorii” but concluded they were not sufficient for identification.

Gracilariophila gardneri is morphologically similar to the 

generitype, G. oryzoides Setchell et H. L. Wilson (in Wilson, 

1910; see Fredericq et al., 1989), an adelphoparasite found on 

Gracilariopsis andersonii (Abbott, 1983:562, as “G. sjoestedtii”) 

of the Pacific Coast from British Columbia to Baja California 

(Dawson, 1961b; Scagel et al. 1989) and on G. cunninghamii

from Baja California Sur (Mateo-Cid and Mendoza-González, 

1994b). The Gulf G. gardneri differs only in tetrasporangia, 

which are irregularly divided versus being strictly, regularly, 

cruciately divided in G. oryzoides. Further investigations of the 

anatomy, host specificity, and DNA are needed to test the relationship of these two species.

Pterocladiophilaceae

Pterocladiophilaceae K.-C. Fan et Papenfuss, 1959:38.

Parasitic algae that are minute, generally more or less spherical, and basally penetrating the tissue of the host and protruding 

above the host’s surface.

Tetrasporangia are cruciately divided. Carpogonial branch 

is 2-celled. Spermatangia are produced in chains, cut off transversely at upper end of spermatangial parent cell.

Remarks. The Pterocladiophilaceae is represented in 

the Gulf by Gelidiocolax, a minute parasitic alga growing on 

species of the Gelidiales (Fan and Papenfuss, 1959).

Gelidiocolax N. L. Gardner

Gelidiocolax N. L. Gardner, 1927c:340.

Parasitic algae that are diminutive, whitish, pale pink or colorless, subspherical to hemispherical tubercules, up to 5 mm in 

diameter, on host species of Gelidium and Pterocladia. Thalli are 

composed of basal-penetrating rhizoids that apparently either 

form or lack secondary pit connections to the host tissue and 

outwardly develop a solid mass of isodiametric cells.

Tetrasporangia are cruciately divided and scattered over the 

thallus surface. The initial stages of gonimoblast development 

are unknown, but the carposporophytes apparently consist of 

a small basal fusion cell and radiating chains of carposporangia 

developed in conceptacle-like chambers in the thallus that have 

an ostiole at the surface. Carposporophytes are surrounded by a 

thick pericarp and grouped in lobes of the thallus. Spermatangia 

are produced from the spermatangial parent cells in rows of 3–4 

and can cover the entire surface.

Remarks. On the basis of significant anatomical and 

morphological similarities to the Gracilariales, Fredericq and 

Hommersand (1990) removed the genera Gelidiocolax and Pterocladiophila K.-C. Fan et Papenfuss (1959; parasites on members 

of the Gelidiales) and Holmsella Sturch (1926; on some Gracilariaceae) from the family Choreocolacaceae Sturch (1926) and 

transferred them to the Pterocladiophilaceae. The molecular data 

of Zuccarello et al. (2004a) supported the placement of Holmsella in the Gracilariales, but they noted that parasitic algae rarely 

infect members outside their family and concluded that molecular 

data are needed to test the family placement of the other genera.

There is one species of this diminutive parasite in the northern Gulf of California.

Gelidiocolax microsphaericus N. L. Gardner

Gelidiocolax microsphaericus N. L. Gardner, 1927c:341; Dawson, 1953a:61; 

1954a:323; Fan and Papenfuss, 1959:33; Dawson, 1961b:410; Stewart, 1976:342, fig. 285; 1991:97; González-González et al., 1996:204; 

L. Aguilar-Rosas et al., 2000:130; Mateo-Cid et al., 2000:64.

Minute parasites, subspherical to hemispherical mounds, 

white to pinkish white, 175–230 μm in diameter, found on some 

members of Gelidiaceae; internally of filaments, dichotomously 

to trichotomously branched, terminating in long, narrow apical, 

surface cortical cells.
NUMBER 96 • 405

Tetrasporangia 22–28 μm in diameter; scattered over surface. Carpogonial branch 2-celled. Cystocarps within thallus; 

carposporangia in dense clusters. Spermatangia, 1.5–2.0 μm in 

diameter; 3–4 seriate on upper ends of outer cortical cells; covering surface of thallus.

Habitat. Adelphoparasite on Gelidium pusillum; 

intertidal.

Distribution. Gulf of California: El Coloradito 

to Puertecitos; Punta Arena. Eastern Pacific: Balboa, southern 

California to Punta Descanso, Baja California; Isla San Martín 

(northwest of San Quintín, Baja California).

Type Locality. On Gelidium pulchrum N. L. Gardner 

(1927b; =Gelidium purpurascens N. L. Gardner, 1927b); ~3.2 km 

south of Balboa Beach, Orange County, southern California, USA.

Cryptonemiales

Cryptonemiales F. Schmitz, 1892:21.

Halymeniales G. W. Saunders et Kraft, 1996:730.

Algae are low growing, repent, or erect and exhibit a wide range 

of morphologies. Species may be narrow to broad, unbranched or 

branched, or foliose blades. Thalli are multiaxial in structure. The 

medulla is filamentous, and the cortex is pseudoparenchymatous. In 

one family, the Halymeniaceae, secondary pit connections are common between cells in the medulla and inner cortical layers.

Member algae have a triphasic life history with isomorphic gametophytes and tetrasporophytes. Tetrasporangia are 

usually cruciately or decussately cruciately divided. Carpogonial 

branches and auxiliary cells are located in separate branch systems (nonprocarpic), and carpogonial branches are from twoto four-celled. After presumed fertilization, carpogonia produce 

multiple septate, branched connecting filaments that transfer the 

zygote nucleus to auxiliary cells. Diploidized auxiliary cells issue 

a single gonimoblast initial, directed thallus outward. The carposporophyte is multilobed with a small fusion cell, and the bulk of 

gonimoblast cells convert to carposporangia.

Remarks. The distinction of the Cryptonemiales and 

Gigartinales has long been debated (e.g., Kraft and Robbins, 1985; 

Abbott, 1999). Saunders and Kraft (1996) clarified the two orders 

and proposed a new name, the Halymeniales, for this order, restricting it to two families. Thus, two names are in current use for 

this order, Cryptonemiales F. Schmitz (1892) and Halymeniales 

G. W. Saunders et Kraft (1996), and there has been much discussion on which of these ordinal names should be used (e.g., Kraft 

and Saunders, 2000; Silva, 2002; Gavio et al., 2005). At present, 

the Botanical Code (McNeill et al., 2006, 2012: Art. 11.10) does 

not require priority for use of taxon names above the rank of family. Therefore, although either name could be used, the ICBN does 

recommend using priority. For now, following Recommendation 

16A, “in choosing among typified names for a taxon above the 

rank of family, authors should generally follow the principle of 

priority,” the name Cryptonemiales is used for this order.

The order is represented by two families in the marine flora 

of the northern Gulf of California.

KEY TO THE FAMILIES OF CRYPTONEMIALES IN THE NORTHERN GULF OF CALIFORNIA

1a. Gulf species membranous (not gelatinous), generally slippery in texture; some cortical filament cells with secondary pit 

connections; carpogonial branch 2- to 4-celled; most genera with separate clusters of accessory sterile filaments (ampullae) 

for each carpogonial branch or auxiliary cell; carposporophyte cupped or surrounded by involucres derived from ampullary filaments, in some genera with additional involucres derived from medullary filaments . . . . . . . . . . . Halymeniaceae

1b. Gulf species gelatinous; cortical filament cells without secondary pit connections; carpogonial branch 3-celled; auxiliary 

cells intercalary in normal cortical filaments; female reproductive structures not in ampullary filament clusters . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tsengiaceae

Halymeniaceae

Halymeniaceae Bory de Saint-Vincent, 1828:158 [as “Halymeniae”]; Guiry, 

1978a:192; Silva, 1980:82.

Cryptonemiaceae Harvey, 1849b:75, 132; Papenfuss, 1955:188; Silva, 

1980:82.

Grateloupiaceae F. Schmitz, 1892, nom. illeg.:18, 21; Schmitz and Hauptfleisch, 1897c:508, fig. 274; Kylin, 1956:213 [see Silva, 1980:82].

Algae are generally erect and simple, divided, or branched, 

with species displaying great variation in habit, being cylindrical, 

compressed, flattened, or blade-like. Thalli are multiaxial in construction, with a filamentous medulla and a cortex of cells that 

become successively smaller toward the surface.

Gametophytes isomorphic with tetrasporophytes. Tetrasporangia are cruciately divided, embedded in the cortex, and either 

(1) scattered over the thallus surface, (2) grouped in sori, or (3) 

borne in modified areas of tissue (nemathecia). Sexual thalli are 

monoecious or dioecious. The carpogonial branch is generally 

two-celled; this branch and the auxiliary cell branch are separate 

from each other (nonprocarpic), and in most genera, each is surrounded by a cluster of special ampullary filaments (accessory 

sterile filaments) that arise from inner cortical cells. Connecting 

filaments develop from fertilized carpogonia and these contact 

and diploidize the auxiliary cell, which then develops the carposporophyte. Cystocarps are embedded in the thallus and in most 

genera are cupped or surrounded by sparse to conspicuous involucres derived mostly from the ampullary filaments (ampullae); 

in some genera, however, additional involucres are derived from 

medullary filaments. Spermatangia are superficial on the thallus, 

cut off from terminal cortical cells.

The Halymeniaceae is represented by four genera in the 

northern Gulf of California.
406 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

KEY TO THE GENERA OF THE HALYMENIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli ranging from narrow, branching fronds to foliose blades; medulla with predominantly periclinal filaments, anticlinal medullary filaments rare to absent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Most thalli foliose blades; medulla with some conspicuous anticlinal filaments . . . . . . . . . . . . . . . . . . . . . . Halymenia

2a. Thalli of thin, flattened blades; blades entire (unbranched), divided, or lobed; cortex thin, 1–3(–6) cell layers; medulla of 

loose periclinally directed filaments, some with dense and refractive contents (these generally wider) . . . . Cryptonemia

2b. Thalli flat, usually thicker; of narrow strap-like branches or subcylindrical and narrow in diameter or compressed, 

flattened blades; cortex of 4 or more cell layers; medulla with lax to congested filaments, filaments without refractive 

contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Texture rigid or cartilaginous; fronds of narrow, strap-shaped branches, usually with few to many laterals; cortex thick, of 

5–12 cells in anticlinal file; medulla packed with filaments; tetrasporangia grouped in sori in outer cortex . . . . . . Prionitis

3b. Thalli lubricous to leathery; of compressed to flattened blades or subcylindrical narrow axes and branches; cortex of 4–8 

cells in anticlinal file; medulla lax to dense throughout (1 species with sparse filaments and a hollow center); tetrasporangia scattered in cortex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Grateloupia

Cryptonemia J. Agardh

Cryptonemia J. Agardh, 1842:100.

Algae are erect, flattened blades that vary in form from 

lanceolate to ovoid or broad and are unbranched or branched, 

lobed or irregularly divided above a stipe that is attached by a 

small discoid holdfast. Some have proliferous branchlets along 

blade margins or the stipitate portion. In at least one species, the 

stipe is perennial and exhibits growth rings. The thallus is typically relatively thin, usually 300 μm or less thick. The medulla is 

composed of predominately periclinally directed filaments; some 

of the medullary filaments may have dense and highly refractive 

contents. The cortex is thin, usually composed of one to four layers of more or less spherical to ellipsoid small cells that become 

progressively smaller toward the surface.

Tetrasporophytes and gametophytes are isomorphic. Tetrasporangia are generally small (<25 μm) and cruciately divided, embedded in the cortex, and scattered over the blade surface. Female 

reproductive structures are borne in ampullae, with ampullary 

filaments branched up to four orders. Carpogonial branches are 

two-celled, borne on a primary or secondary ampullar filament. 

The hypogynous cell may develop a sterile filament. Auxiliary cell 

ampullae are slightly more complex; the auxiliary cell is a basal or 

suprabasal cell of a second- or third-order ampullary filament in 

a branch system separate from those of the carpogonial branches. 

After fertilization, connecting filaments are issued by the carpogonia and contact auxiliary cells, where a small auxiliary fusion cell 

is formed. A single gonimoblast initial arises from the diploidized 

auxiliary cell and produces a compact carposporophyte of many 

small carposporangia. The surrounding pericarp is slight, formed 

by elongated ampullary filament cells. Cystocarps are embedded 

and scattered, slightly distending the blade surface. Spermatangia, 

where known, are superficial over the thallus.

Remarks. One Pacific Mexico species, Cryptonemia 

decolorata W. R. Taylor (1945; type locality: Isla María Magdalena, Islas Marías) described from the southernmost entrance to 

the Gulf off Nayarit, has been also reported in the southern Gulf, 

from Bahía Concepción (Mateo-Cid et al., 1993).

There are five species of Cryptonemia in the northern Gulf 

of California, two of which are endemic to the Gulf.

KEY TO THE SPECIES OF CRYPTONEMIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Blades generally smaller; lobed, pseudodichotomously or irregularly branched; up to 15 mm wide . . . . . . . . . . . . . . . . 2

1b. Blades larger, ovate to obovate or broadly lanceolate; simple, lobed, or divided; more than 15 mm wide . . . . . . . . . . . 4

2a. Blade with distinctively lobed, orbicular-shaped bladelets from margins of central blade (resemble Opuntia cactus pads), 

up to 9 mm in diameter; up to 50 μm thick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. opuntioides

2b. Blades divaricately, pseudodichotomously or irregularly branched . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Blades irregularly dividing, often becoming much lacerated; up to 15 mm wide; 80–90 μm thick . . . . . . . . C. veleroae

3b. Blades distinctly and divaricately pseudodichotomously branched, at times repeatedly; (2.0–)3–15 mm wide; 40–

70(–110) μm thick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. guaymasensis

4a. Blades ovate to obovate, entire or only once or twice lobed; membranous; 4–30 cm tall and wide; 120–300(–450) μm 

thick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. obovata

4b. Blades ovate to broadly lanceolate, usually divided (rarely entire), or dichotomously or pinnately branched; 5–14 cm tall, 

2–6 cm wide; more delicate, thinner; 35–100 μm thick; margins sometimes with small lateral bladelets . . . .. C. angustata

Cryptonemia angustata (Setchell et N. L. Gardner) E. Y. 

Dawson

FIGURE 203

Kallymenia angustata Setchell et N. L. Gardner, 1937:77 [as “Callymenia 

angustata”], pl. 3: fig. 6b, pl. 12: fig. 32; Dawson, 1944a:285, pl. 68: 

fig. 1.
NUMBER 96 • 407

Cryptonemia angustata (Setchell et N. L. Gardner) E. Y. Dawson, 1954c:261, 

pl. 2: figs. 11–14; 1960a:45; Dawson et al., 1960a:56, pl. 24: fig. 3; 

Dawson, 1961b:422; 1961c:413, pl. 19: fig.3; Dawson et al., 1964:50, 

pl. 56: fig. B; Dawson, 1966a:21; Abbott, 1967a:147 [in part], figs. 

9, 10; Abbott and Hollenberg, 1976:437 [in part], fig. 387; Stewart, 

1991:89; Ramirez and Santelices, 1991:229; González-González et al., 

1996:195; Pacheco-Ruíz and Zertuche-González, 2002:467; MateoCid et al., 2006:52; Dreckmann et al., 2006:155; Serviere-Zaragoza et 

al., 2007:9; Pacheco-Ruíz et al., 2008:207; Bernecker, 2009:CD-Rom 

p. 63; Fernández-García et al., 2011:61.

Kallymenia tenuifolia W. R.Taylor, 1945:214 [nom. illeg.], pl. 72: figs. 1–4 

[non Kallymenia tenuifolia Feldmann, 1935:368].

Algae membranous, ovate to broadly lanceolate blades, rose 

red, 5–14 cm tall, 2–6 cm wide; arising from a short distinct 

stipe; attached below by a small discoid holdfast. Blades simple 

or pinnately divided, sometimes with irregular proliferations; 

blades stipitate. Blades 35–60 μm thick in smaller blades and 

can be up to 90(–100) μm thick in larger thalli. Medulla of a 

few, slender, longitudinally aligned filaments, some thicker and 

with dense refractive contents. Cortex of (1–)2–3 cell layers; 

outer cortical cells 3–8(–10) μm in diameter; inner cortical cells 

slightly larger.

Tetrasporangia cruciately divided, 20 μm or less in diameter 

in surface view; scattered in cortex over blade. Cystocarps up 

to 200 μm in diameter, surrounded by a few sterile (ampullary) 

filaments; embedded within thallus and bulging blade surface; 

scattered over blade. Spermatangia not seen.

Habitat. Occasional on shaded rocks and tide pools, 

low intertidal, down to 10 m depths; dredged from 30–84 m 

depths.

Distribution. Gulf of California: Puerto Peñasco; 

Bahía Tepoca to Punta La Gringa, Bahía de Los Ángeles; Bahía 

de San Lucas. Eastern Pacific: Monterey Bay, central California, 

and La Jolla, southern California; Isla Magdalena, Bahía Magdalena (Baja California Sur); Isla Socorro (Islas Revillagigedo); 

Chiapas; El Salvador; Costa Rica; Peru.

Type Locality. Bahía Santa María, west coast of 

Isla Magdalena (outside Bahía Magdalena), Baja California Sur, 

Pacific Mexico.

Remarks. Cryptonemia angustata, described from 

Pacific Baja California Sur, is predominately a warm-temperate 

to subtropical species. Gabrielson et al. (2004) noted that as reported in colder waters of the northeast Pacific, C. angustata,

C. obovata J. Agardh (1876), and C. borealis Kylin (1925) can 

be difficult to separate and are in need of reinvestigation. The 

northern California C. obovata and the Washington C. borealis

are both cool- to cold-temperate species. Morphologically, Gulf 

of California specimens referred to C. angustata are close to C. 

veleroae (E. Y. Dawson) E. Y. Dawson (see also Remarks under 

C. veleroae) and should be critically compared.

FIGURE 203. Cryptonemia angustata: Habit of a tetrasporophyte (JN-4500, US Alg. Coll.-158994).
408 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Cryptonemia guaymasensis (E. Y. Dawson) E. Y. Dawson

FIGURE 204A,B

Kallymenia guaymasensis E. Y. Dawson, 1944a:286, pl. 68: fig. 2 [as “Callymenia guaymasensis”].

Cryptonemia guaymasensis (E. Y. Dawson) E. Y. Dawson, 1954c:263; 

1960a:45; 1961b:422; 1966a:21; Lewis, 1990: fig. 6 [holotype]; 

González-González et al., 1996:195; L. Aguilar-Rosas et al., 2000:130; 

CONANP, 2002:139; Mateo-Cid et al., 2006:52.

Algae of strap-like axes in lower portion, subdichotomously 

divided above, usually branched; dark rose red, mostly 5–7 cm tall, 

5.0–15 mm wide; smaller in intertidal, up to 3 cm tall and (2.0–) 

3.0 mm wide; arising from subcylindrical to compressed stipes, 2–5 

mm long; attached by a small discoid holdfast. Axes with round 

apices, margins sometimes undulate. Intertidal algae up to 110 μm 

thick, with stipe sometimes extending into base of blade as a midrib, occasionally extending to first division. Subtidal algae 40–70 

μm thick; midrib lacking. Branching divaricately subdichotomous 

in 1 plane; sometimes secondary proliferations from margins. Medulla narrow, of branched interwoven filaments; some with dense 

refractive contents. Cortex of 2–3(–4) cell layers; subcortex 1–2 

layers of rotund cells, 8–12 μm in diameter; outer cortex of 1 layer 

(rarely 2) of small pigmented cells, 4–6 μm in diameter.

Tetrasporangia unknown. Cystocarps 200–250 μm in diameter; embedded, bulging (more prominent on side with ostiole); 

scattered over blade surface; carposporangia in compact mass, 

appearing pedicellate (borne on persisting auxiliary cell). Spermatangia unknown.

Habitat. On sides of rocks, in crevices, and on side 

walls of deeper tide pools; low intertidal to shallow subtidal, 

down to 6 m depths; also dredged from 8–37 m depths (Dawson, 

1954c).

Distribution. Gulf of California: Playa Las Conchas (Playa Estacíon), Puerto Peñasco to Guaymas; El Coloradito to Santa Teresa; Bahía de Loreto to Bahía de San Lucas. 

Eastern Pacific: Costa Rica.

Type Locality. On muddy bottom, 4–6 m depths; 

outer harbor, Guaymas, Sonora, Gulf of California, Mexico.

Remarks. Intertidal specimens identified as Cryptonemia guaymasensis from Puerto Peñasco (Dawson, 1966a) are 

3–4 mm wide and 1–3 cm tall, smaller overall than those reported elsewhere in the Gulf (Dawson, 1954c). Once thought to 

be a Gulf endemic (Dawson, 1954c), Cryptonemia guaymasensis

has also been reported from Pacific Costa Rica (Dawson, 1960a; 

Bernecker, 2009 [CD-Rom], as “C. limensis”; Fernández-García 

FIGURE 204. Species of Cryptonemia. A, B. Cryptonemia guaymasensis: Habits of two thalli 

(EYD-27492, US Alg. Coll.-40772). C. Cryptonemia opuntioides: Habit of holotype (EYD-26126, 

US Alg. Coll. microscope slide 786).
NUMBER 96 • 409

et al., 2011, as “C. limensis”) and in the western Atlantic from 

Brazil (Pinheiro-Joventino, 1977; Creed et al., 2010). Lewis 

(1990) included C. guaymasensis as a synonym of C. limensis

(Sonder ex Kützing) J. A. Lewis (basionym: Euhymenia limensis Sonder ex Kützing, 1849), a species from Peru and northern Chile (Ramírez and Santelices, 1991, as “Sebdenia limensis

(Sonder ex Kützing) M. Howe, 1914”). After more fertile specimens from the Gulf of California are collected, especially from 

the type locality, a critical morphological and molecular systematic study is needed to evaluate the taxonomic status of Gulf 

C. guaymasensis and its relationship to South American C. 

limensis.

Cryptonemia obovata J. Agardh

FIGURE 205

Cryptonemia obovata J. Agardh, 1876:681; Kylin, 1925:10, fig. 8a; Dawson, 

1954c:260, pl. 1: figs. 9, 10; Dawson et al., 1960a:56, pl. 25: figs. 3, 

4; 1960b:18; Dawson, 1961b:422; Hollenberg and Abbott, 1966:68, 

figs. 26, 27; Abbott, 1967a:145; Acleto O., 1973:41, 124, 127–128; 

Abbott and Hollenberg, 1976:438, fig. 389; Silva, 1979:318; Norris, 

1985d:210; Scagel et al., 1989:171; Stewart, 1991:89, fig. 6; GonzálezGonzález et al., 1996:308.

Algae membranous, ovate to obovate blades, 4–30 cm 

tall, arising from a short-branched stipe; attached below by a 

small conical holdfast. Blades mostly reddish brown, simple or 

divided or torn, sometimes with secondary blades; firm in texture, margins entire; (65–)100–250(–450) μm thick. Medulla of 

intertwined predominately periclinally directed filaments; some 

medullary filaments with highly refractive contents. Cortex of 

3–6 rows of cells; inner cortical cells oval, gradually becoming 

smaller outward; outer cortical cells slightly elongated.

Tetrasporangia cruciately divided, scattered in outer cortex 

over thallus. Cystocarpic and spermatangial plants unknown in 

Gulf material.

Habitat. Rare, attached to shells or rocks, mud-sand 

bottom; subtidal, 14 m depth.

Distribution. Gulf of California: Canal de Infiernillo (between Isla Tiburón and El Desemboque, Sonora); Isla 

San Esteban. Eastern Pacific: Alaska to Cabo Tórtolo (off south 

entrance to Bahía Tortugas [Bahía San Bartolomé]), Baja California Sur; Peru; Chile.

Type Locality. San Francisco Bay entrance (probably Fort Point, vicinity of Golden Gate Bridge), San Francisco, 

San Francisco County, northern California, USA.

FIGURE 205. Cryptonemia obovata: A. Habit of small blade (JN-4729, US Alg. Coll.-158996). B. Habit of large blade (EYD21577, US Alg. Coll.-7069). C. Diagrammatic transection of C. obovata.
410 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Remarks. Cryptonemia obovata is generally recognized by its reddish brown color and larger and thicker blades 

than other Cryptonemia species in the Gulf.

Cryptonemia opuntioides E. Y. Dawson

FIGURE 204C

Cryptonemia opuntioides E. Y. Dawson, 1966b:59, fig. 6F; GonzálezGonzález et al., 1996:195; Pacheco-Ruíz and Zertuche-González, 

2002:467; Pacheco-Ruíz et al., 2008:207.

Algae up to 1.5 cm tall, with orbicular blades originating 

from margins of a central blade, attached below by a small discoid holdfast. Secondary orbicular blades, up to 9 mm in diameter (shaped like Opuntia cactus pads); borne on short stipes 

from eroded or grazed margins of primary blade; blades very 

thin, about 50 μm thick. Medulla of a few slender, mostly periclinally directed filaments, many with dense refractive contents. 

Cortex mostly 2 rows of cells; inner cortex of rotund cells, up to 

11 μm in diameter; outer cortex a single layer of small cells, to 

7 μm in diameter.

Tetrasporophytes unknown. Cystocarps 250–275 μm in diameter, to 225 μm thick, prominently bulging on both sides of 

blade, scattered throughout blade. Spermatangia unknown. 

Habitat. Poorly known, subtidal, 12–18 m depths.

Distribution. Gulf of California: Isla La Ventana, 

Bahía de Los Ángeles; Isla Salsipuedes.

Type Locality. Isla Salsipuedes, Islas de San Lorenzo (Islas de la Cintura), off Baja California, Gulf of California, Mexico.

Remarks. Cryptonemia opuntioides is apparently a 

northern Gulf endemic and restricted to the subtidal.

Cryptonemia veleroae (E. Y. Dawson) E. Y. Dawson

Kallymenia veleroae E. Y. Dawson, 1944a:285 [as “Callymenia veleroae”], 

pl. 45: fig. 1; Hernández-Kantún et al., 2010:1.

Cryptonemia veleroae (E. Y. Dawson) E. Y. Dawson, 1954c:262; 1961b:423; 

González-González et al., 1996:196; Silva et al., 1996b:233.

Blades up to 4 cm tall; initially simple and entire, obovate 

to oblanceolate, becoming split (divided) and forming additional 

divisions; lower portion of blades up to 8 mm wide, cuneate at 

the short, narrow, flattened stipe; upper portions up to 15 mm 

wide. Blades mostly 80–90 μm thick; medulla of longitudinal filaments, 5–6 μm in diameter, 30–65 μm long; inner cortex of 1–2 

layers of periclinally elongated cells, 10–20 μm tall; outer cortex 

a single layer of small pigmented cells, 5–7 μm in diameter.

Tetrasporophytes unknown. Cystocarps not described. 

Spermatangia grouped together and separated by sterile cells in 

superficial sori (see Dawson, 1954c).

Habitat. Subtidal, 10–20 m depths.

Distribution. Gulf of California: Rocas Consag; 

Guaymas.

Type Locality. Outside Guaymas Harbor entrance, 

Guaymas, Sonora, Gulf of California, Mexico.

Remarks. Although poorly known, Cryptonemia 

veleroae is apparently close to C. angustata (Dawson, 1944a, 

1954c), and later, the two were considered to be conspecific 

(Abbott, 1967a). Recognition of C. veleroae as a distinct species is problematic, primarily on the basis of differences seen in 

comparably sized blades: in C. veleroae they are deeply divided 

and show progressive lacerations and thicker blades (80–90 μm), 

whereas those of C. angustata are simple ovate and later divided 

blades with broadly lanceolate segments and are thinner (35–60 

μm). For now, both taxa are recognized in the northern Gulf, until 

their taxonomic status can be elucidated with molecular evidence.

Grateloupia C. Agardh

Grateloupia C. Agardh, 1822:221.

Algae are erect, terete (at least basally in some), compressed 

or flattened, and lanceolate, linear, or foliose, above a cylindrical 

to compressed stipe that is attached below by a discoid holdfast. Thalli are simple, entire, lobed, or much divided or irregularly, dichotomously, subdichotomously, pinnately, or palmately 

branched in one or more planes. Some occasionally have proliferous branchlets. Surfaces are lubricous to leathery in texture 

and are usually mostly smooth, although some have short surface proliferations. Multiaxial in structure, the medulla is relatively sparse, composed of colorless filaments (mostly periclinal), 

sometimes with rhizoidal filaments. Some cells have long processes, called stellate or ganglionic cells, especially in the outer 

medulla and inner cortex. The cortex varies in thickness among 

the species, with an inner cortex of rounded to rotund cells and 

an outer cortex composed of anticlinal rows of progressively 

smaller cells toward the surface.

Tetrasporophytes and gametophytes are isomorphic. Tetrasporangia are cruciately divided, embedded in the outer cortex, 

and scattered over the thallus. Gametophytes are monoecious or 

dioecious. Carpogonial branches and auxiliary cells are in separate accessory branch systems (ampullae). Ampullary filaments 

are sparingly branched, usually only to one or two orders. Auxiliary cell ampullae consist of a primary filament and one to three 

unbranched secondary filaments. Carpogonia are terminal on a 

two-celled carpogonial branch on a primary ampullar filament. 

After fertilization, connecting filaments develop and can fuse 

with a succession of auxiliary cells located in separate ampullae. 

A small auxiliary fusion cell is formed, and a single, outwardly 

directed gonimoblast initial produces a compact cystocarp of 

many small carposporangia, embedded within the thallus, surrounded by moderate involucres derived from both medullary 

and ampullary filaments. Cystocarps are usually conical in outline with a small ostiole. Spermatangial parent cells formed from 

surface cells and spermatangia are borne superficially in whitish 

sori or scattered over the blade surface.

Remarks. The species of Grateloupia in the Gulf of 

California have a firm, but slippery, lubricous texture and often 

are quite elastic when fresh. In the Gulf, the foliose Grateloupia can be distinguished from other foliose red species by their 

smooth or proliferous surface, slippery texture, and darker color, 

often iridescent, brown-mahogany, greenish purple, or deep violet. The exception to this is the very large foliose, G. violacea,

that is a distinctive iridescent rose red when fresh.
NUMBER 96 • 411

Grateloupia species are economically important as a food 

(Kumari et al., 2010), producers of carrageenan (Critchley 

and Ohno, 1998; Critchley et al., 2006), and bioactive natural 

products (Wang et al., 2007). Those of the Gulf of California, such as G. violacea, warrant further investigations. However, once introduced into marine habitats, nonnative species 

of Grateloupia are among the most invasive (Inderjit et al., 

2006). Japanese Grateloupia turuturu Yamada (1941; shown 

by Gavio and Fredericq, 2002, to be correct name for Altantic 

“G. doryphora”) has been found in major shipping ports in 

the North Atlantic (Miller et al., 2011), most likely introduced 

via ship ballast waters (Villalard-Bohnsack and Harlin, 2001), 

hull fouling and aquaculture (Hewitt et al., 2007), and also 

possibly transported by boats and yachts. In the Pacific, G. turuturu was discovered in the port of Ensenada, Baja California, 

in 2008 (Aguilar-Rosas in Miller et al., 2011), and in California 

in 2009 at Santa Barbara Harbor (Hughey et al., 2009) and 

2010 in Half Moon Bay (Miller et al., 2011). The potential 

introduction of nonnative Grateloupia could cause problems 

in the Gulf of California, and the ports and harbors, including 

those of Puerto Peñasco, Bahía San Carlos, Guaymas, La Paz, 

and Mazátlan, should be monitored by methods such as those 

given by Meinesz (2007).

The genus, Sinotubimorpha W.-X. Li et Z.-F. Ding (1998; 

generitype: S. porracea (Mertens ex Kützing) W.-X. Li et Z.-F. 

Ding; basionym: Grateloupia porracea Mertens ex Kützing, 

1843) was distinguished from Grateloupia by its hollow thallus, 

secondary filaments in the ampullae, one- to three-celled carpogonial branches, and one- to four-celled sterile filaments on the 

carpogonium. Subsequently, Wang et al. (2000) and Sheng et al. 

(2012) found no morphological or genetic support for the separation of these genera.

With seven species, Grateloupia is well represented in the 

northern Gulf of California.

KEY TO THE SPECIES OF GRATELOUPIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Large, long and wide, flat blades; more than 1 cm in width, mostly 3–8 cm (up to 20 cm wide); up to 30–55 (or more) 

cm in length; rose red to dark violet or brownish . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Fronds much narrower, less than or only up to 1(–2) cm in width; shorter, up to 12(–20) cm tall; compressed or flattened 

(some more or less terete in portions), more or less lanceolate or linear and much branched; red to dark red or greenish 

purple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2a. Thalli with smooth surfaces and entire margins; rose red; up to 55 cm long (largest to 230 cm), more than 5 (up to 20) cm 

wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. violacea

2b. Thalli surfaces and margins with numerous spine-like proliferations or short papillose branchlets; brownish mahogany 

to dark brownish black; up to 30 cm long, usually less than 8 cm wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. howei

3a. Axes mostly 10(–20) mm wide, branching in 1 plane, predominately and abundantly pinnate; axes surface smooth or 

with slender short proliferous branchlets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. prolongata

3b. Axes mostly less than 5 mm wide, branching in 1 plane (distichous) or more than 1 plane (multifarious) . . . . . . . . . . 4

4a. Branching in more than 1 plane . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

4b. Branching in 1 plane or dichotomous to subdichotomous . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

5a. Mostly over 8 cm tall; medulla filaments very sparse and loose; central portion of medulla hollow; ultimate branchlets 

catenate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. catenata

5b. Mostly less than 4 cm tall; medulla filaments not sparse; medulla solid (without a hollow center); ultimate branchlets not 

catenate. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. hancockii

6a. Branched dichotomous to subdichotomous; branches up to 2.5 mm wide . . . . . . . . . . . . . . . . . . . . . . . . G. dactylifera

6b. Branching partly pinnate to irregular; branches up to 4 mm wide; variegated dark greenish purple, usually iridescent

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. versicolor

Grateloupia catenata Yendo

FIGURE 206

Grateloupia catenata Yendo, 1920:9; Wang et al., 2000:228–234, figs. 1 [lectotype], 2–19; De Clerck et al., 2005b:392, tbl. 1.

Sinotubimorpha catenata (Yendo) W.-X. Li et Z.-F. Ding in Xia, 2004:141, 

fig. 83, pl. 13: fig. 1.

Grateloupia filicina var. lomentaria M. Howe, 1924:142, pl. 1: figs. 2–4, 

pl. 2: figs. 1–5; Okamura, 1936:540; Dawson, 1950b:155, fig. 29; 

1954c:253; 1966a:20; Dawson and Neushul, 1966:177; GonzálezGonzález et al., 1996:218; Mateo-Cid et al., 2006:51.

Grateloupia filicina var. porracea f. lomentaria (M. Howe) Okamura, 

1936:540.

Lomentaria drouetii E. Y. Dawson, 1944a:309, pl. 46: figs. 1, 2, pl. 74: fig. 2; 

González-González et al., 1996:242.

Sinotubimorpha porracea sensu Li and Ding, 1998:1 [in part, Chinese specimens only; non Sinotubimorpha porracea (Mertens ex Kützing) W.-X. 

Li et Z.-F. Ding, 1998:1; which is now Grateloupia porracea Mertens 

ex Kützing, 1843:397 (type locality: West Indies)].

Grateloupia filicina sensu Dawson, 1954c:252; 1961b:422 [non Grateloupia 

filicina (J. V. Lamouroux) C. Agardh, 1822:223; basionym: Delesseria 

filicina J. V. Lamouroux, 1813:125].

Algae of 1 to several terete to compressed axes, 8–12(–20) 

cm tall; multifariously, or pinnately branched, 2–5 orders; arising 

from a small discoid holdfast. Axes mostly 1.5–2.0(–3.0) mm in 

diameter, with narrower branches, 700–1000 μm in diameter; ultimate branchlets short, more slender, less than 200 μm in diameter, usually with 1 or 2 constrictions (catenate proliferations), 

attenuated upward. Internally with a medulla of sparse, slender, 
412 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

branched filaments, 7–8 μm in diameter; inner medulla often 

partly or entirely hollow. Inner cortex of (1–)2 layers, sometimes 

partially incomplete, of more or less rotund cells; outer cortex of 

anticlinal rows of 2–3 smaller cells.

Tetrasporangia scattered in cortex; 35–40 μm tall, 18–20 

μm in diameter. Cystocarps immersed in cortex, scattered over 

thallus. Spermatangia not observed in Gulf specimens.

Habitat. On rocks and tidal platforms; intertidal to 

shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía de Topolobampo; Mazatlán, Sinaloa to Nayarit. Eastern Pacific: Anacapa Island (California Channel Islands); northern Baja California. Western Pacific: China; Japan; Korea.

Type Locality. Syntype localities of Yendo 

(1920:10); Japan: Honshū Island: Tsugaru and [Cape] Tappizaki, Shimofuro and Ajigasawa (Aomori Prefecture), and Fukuyama (Hiroshima Prefecture); and Hokkaidō Island (Hokkaidō

Prefecture): Hokodate. Lectotype locality: Ajigasawa, Aomori 

Prefecture (northern Honshū Island), Japan (Wang et al., 2000: 

fig. 1).

Remarks. Gulf specimens tentatively referred to 

Grateloupia catenata are in agreement with the interpretation of 

Dawson (1950b, 1954c), who concluded that most Gulf material 

closely resembled G. filicina var. lomentaria (Howe, 1924). The 

latter, described from China (type locality: Pei-tai-ho (Beidaihe), 

Hebei Province), is now considered to be a synonym of the Japanese G. catenata Yendo (Wang et al., 2000; De Clerck et al., 

2005b).

H.-W. Wang et al. (2000) found no basis for the generic 

separation of Sinotubimorpha W.-X. Li et Z.-F. Ding (1998) 

from Grateloupia. Although S. porracea was considered to be 

conspecific with S. catenata (Yendo) W.-X. Li et Z.-F. Ding (in 

Xia, 2004), this was not supported by Wang et al. (2000), who 

recognized the western Pacific G. catenata and the western Atlantic G. porracea as distinct species.

The Gulf Grateloupia catenata also resembles G. avalonae

E. Y. Dawson (1949b) from the California Channel Islands in 

habit but differs from it primarily in being centrally hollow. Morphological and molecular systematics of these taxa should clarify 

their taxonomic status and the identification of Gulf G. catenata.

FIGURE 206. Grateloupia catenata: A. Habit. B. Transection of compressesd axis showing hollow medulla (center) (A, B, JN-6058, US Alg. 

Coll.-159869, microscope slide 8684).
NUMBER 96 • 413

Grateloupia dactylifera E. Y. Dawson

Grateloupia dactylifera E. Y. Dawson, 1954c:257, pl. 10: fig. 53; 1961b:422; 

González-González et al., 1996:217.

Algae solitary or in clumps, up to 4 cm tall, of 1 or more 

flat, branched fronds, axes up to 2.5 mm wide, 200–300 μm 

thick; with or without a very short stipe above a small irregularly 

shaped disc. Branching dichotomously to subdichotomously divaricate, up to 9 orders; widest near base, narrowing in width 

upward; ultimate branches somewhat “hand-like.” Medulla of 

loose to moderately dense periclinal filaments, up to 5 μm in 

diameter. Inner cortex of angular to “arachnoid” cells; outer 

cortex of anticlinal rows of 3–4 small cells, 3–4 μm in diameter.

Tetrasporangia not known. Cystocarps 120–130 μm in 

diameter, embedded and bulging from either side in middle to 

upper portions of thallus; carposporangial mass subglobose to 

reniform and “pedicellate” on modified auxiliary cell; carposporangia up to 14 μm in diameter. Spermatangia unknown.

Habitat. On rocks; mid to low intertidal.

Distribution. Gulf of California: Ensenada de San 

Francisco; Bahía San Gabriél, Isla Espíritu Santo.

Type Locality. Ensenada de San Francisco, vicinity 

of Guaymas, Sonora, Gulf of California, Mexico.

Remarks. Apparently a Gulf endemic, Grateloupia 

dactylifera is known from only a few specimens. More specimens, particularly reproductive ones, are need to evaluate its 

taxonomic status.

Grateloupia hancockii E. Y. Dawson

FIGURE 207

Grateloupia hancockii E. Y. Dawson, 1944a:280, pl. 69: fig. 2; 1950b:155; 

1954c:254, pl. 1: figs. 7, 8; 1961b:422; Dreckmann et al., 1990:30; 

González-González et al., 1996:218; Pacheco-Ruíz et al., 2008:207.

Algae clumps, 2–3(–7) cm tall, of several abundantly 

branched, mostly nonpercurrent axes arising from a small discoid holdfast. Axis compressed, narrow, to 1 mm wide, 300–

400(–700) μm thick; multifariously branched throughout, 

mostly irregularly, but appearing pinnate, to 2–3 orders; ultimate branchlets sometimes attenuated to acute tips. Medulla of 

slender, branched filaments; sparse and interlaced toward center; 

dense and mostly longitudinally aligned, adjoining inner cortex. 

Cortex 7–8 cells thick; inner cortex of 1–2 layers of large cells, 

12–15 μm in diameter, giving rise to anticlinal filaments of small 

cells, to 5 μm in diameter.

Tetrasporangia embedded in cortex and scattered over thallus. Cystocarps embedded and scattered throughout thallus. 

Spermatangia superficial on thallus surface.

Habitat. On rocks; mid to low intertidal, shallow 

subtidal down to 1 m depth.

Distribution. Gulf of California: Bahía La Choya 

(Bahía Cholla, vicinity of Puerto Peñasco) to Guaymas; Isla Estanque, off southeast end of Isla Ángel de la Guarda (Islas de la 

Cintura). Eastern Pacific: Michoacán.

Type Locality. “Rocky headland about 3 miles 

north of Kino,” Bahía Kino, Sonora, Gulf of California, Mexico 

(Dawson, 1944a).

Remarks. Grateloupia hancockii forms dark greenish red to brownish red clumps on intertidal rocks. In the northern Gulf G. hancockii can be distinguished from the similar-sized, 

clumped forms of G. catenata by its distinctly solid (nonhollow) 

medulla and stiffer branches (Dawson, 1954c). A northern Gulf 

species that was originally thought to be restricted in distribution to Sonora (Dawson, 1954c), G. hancockii’s distribution is 

now extended northward to Bahía La Choya (JN-5894, US Alg. 

Coll.-159782) and is also reported from the south end of Isla 

Estanque (Islas de la Cintura) (JN-5597, US Alg. Coll.-159781). 

Dreckmann et al. (1990) report G. hancockii from Michoacán, 

indicating its presence south of the Gulf of California in Pacific 

Mexico.

Grateloupia howei Setchell et N. L. Gardner

FIGURE 208

Grateloupia howei Setchell et N. L. Gardner, 1924:782 [as “G. howeii”], pl. 

83; Dawson, 1944a:281; 1950b:153, fig. 28; 1954c:246, pl. 1: fig. 2, pl. 

6: fig. 47; 1959a:6, 22; Dawson et al., 1960a:64, pl. 25: fig.1; 1960b:10; 

Dawson, 1961b:422; Chávez-Barrear, 1972b:269; Huerta-Múzquiz, 

1978:335; Stewart and Stewart, 1984:144; Mendoza-González and 

Mateo-Cid, 1992:17; Serviere-Zaragoza et al., 1993a:483; MateoCid et al., 1993:47; Mateo-Cid and Mendoza-González, 1994b:39; 

Mendoza-González et al., 1994:106; González-González et al., 

FIGURE 207. Grateloupia hancockii: A, B. Habit variations (A, JN5597, US Alg. Coll.-159781; B, JN-5894, US Alg. Coll.-159782).
414 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 208. Habits of Grateloupia howei: A. Mature thallus 

with numerous spinose papillae on surface and margins, and 

proliferous bladelets along margins (JN-5519, US Alg. Coll.-

159785). B. Juvenile thallus (JN-5920, US Alg. Coll.-159790).
NUMBER 96 • 415

1996:218, 354: fig. 33; Riosmena-Rodriguez et al., 1998:27; PachecoRuíz and Zertuche-González, 2002:467; Pacheco-Ruíz et al., 2008:207.

Gigartina eatoniana sensu Dawson, 1944a:301 [not Gigartina eatoniana

J. Agardh, 1899:15].

Thalli of 1 to several complanate blades, lubricous in texture, up to 30 cm tall; arising from a discoid holdfast. Blades 

simple, divided, or pinnately branched; 450–800 μm thick; margins usually with proliferous bladelets; surface covered in varying degrees with few to numerous short papillate and spinose 

outgrowths. Medulla a loose network of slender, branched filaments, 2.5–3.0 μm in diameter. Cortex of 8–10 cell layers; the 

outer 4–5 cells small and in anticlinal filaments.

Tetrasporangia 32–40 μm long, 9–14 μm in diameter, embedded in cortex and scattered over upper portions of blades. 

Cystocarps embedded and slightly raising thallus surface, scattered over blade and appearing as minute warts among spinose 

outgrowths. Spermatangia superficial on blade surface.

Habitat. On rocks, low intertidal to shallow subtidal, down to 15 m depths.

Distribution. Gulf of California: Puerto Lobos 

to Roca El Solitario (off northern Bahía Agua Verde); Isla San 

Pedro Mártir; Isla San Esteban; Mazatlán, Sinaloa to Jalisco. 

Eastern Pacific: Isla Guadalupe; Isla Cedros; Isla San Benito; 

Punta María, Baja California, to Todos Santos, Baja California 

Sur; Guerrero.

Type Locality. Isla San Esteban (Islas de la Cintura), Gulf of California, Mexico.

Remarks. Variable in size and shape, some specimens 

of Grateloupia howei superficially may look “Chondracanthuslike.” In the field, blades of G. howei can be distinguished from 

Chondracanthus by their lubricous texture, mahogany (brownish reddish) color, and short proliferations on both surfaces and 

margins of the blades.

Grateloupia prolongata J. Agardh

FIGURE 209

Grateloupia prolongata J. Agardh, 1847:10; Kützing, 1867:7, pl. 24: figs. 

a,b; Setchell and Gardner, 1924:780, pl. 80; Dawson, 1944a:279; 

1945b:24; 1954c:248, pl. 7: fig. 49; 1959a:10, 22; 1961b:422; Abbott 

and Hollenberg, 1976:435, fig. 385; Pacheco-Ruíz and Aguilar-Rosas, 

1984:72, 76; Stewart, 1991:91; R. Aguilar-Rosas and Aguilar-Rosas, 

1994:521; González-González et al., 1996:218; CONANP, 2002:140; 

Pacheco-Ruíz and Zertuche-González, 2002:467; López et al., 2004:11; 

Xia, 2004:125, fig. 72 (1–6), pl. 12: fig. 2; Hernández-Herrera et al., 

2005:147; Pacheco-Ruíz et al., 2008:207.

Grateloupia prolongata Liebmann ex Kützing, 1849:730, nom. illeg. [later 

homonym].

Algae of compressed to flattened, ligulate fronds, up to 

20(–50) cm long, expanding above a stipitate portion from cuneate lower portion; upward to 1–2(–3) cm in width; 250–400 

μm thick; arising from a small discoid holdfast. Frond margins 

usually with numerous, pinnate lateral branchlets, narrow (less 

than 10 mm) and up to 15 cm long; these often with abundant 

secondary pinnate bladelets. Blade surfaces smooth or sometimes 

with scattered, short, slender proliferations. Medulla of loose 

slender filaments; sometimes very sparse. Inner cortex of 1–2 

layers of large cells adjoining an outer cortex of small pigmented 

cells in anticlinal rows, 5–6 cells in length.

Tetrasporangia embedded in cortex and scattered over 

thallus. Mature tetrasporangia 40–50 μm long, 10–15 μm in 

diameter, among somewhat elongate cortical cells. Cystocarps 

embedded, slightly bulging, and scattered over thallus. Spermatangia unknown in Gulf material.

Habitat. On rocks; low intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Lobos to 

Guaymas; Isla San Pedro Nolasco; Bahía de Los Ángeles to Bahía 

de Loreto. Eastern Pacific: Goleta, southern California to Salina 

Cruz, Oaxaca. Western Pacific: China.

Type Locality. In describing Grateloupia prolongata, J. Agardh (1847:10) gave the locale as “Pochetti”; Dawson 

(1954c) later listed this locality with the added comment “probably on the coast of Oaxaca.” Kützing (1849:730) stated the 

locale as “Guatulco (Mexico),” probably Huatulco, Oaxaca. De 

Clerck et al. (2005b:392) gave the locale as “Pochutla” (Oaxaca), Pacific Mexico (note that Pochutla is Spanish for the place 

of pochotes; pochote is the Spanish name for the Mexican tree

species of Ceiba [Malvaceae]).

Grateloupia versicolor (J. Agardh) J. Agardh

FIGURE 210

Grateloupia sternbergii var. versicolor J. Agardh, 1847:10.

Grateloupia versicolor (J. Agardh) J. Agardh, 1851:181; De Toni, 1905:1565; 

Dawson, 1954c:256, pl. 6, fig. 48; 1959a:7, 22; 1961b:422; 1961c:423, 

pl. 20: fig. 3; 1962b:208, fig. 101; 1966a:20; 1966b:59; HuertaMúzquiz, 1978:338; Mendoza-González and Mateo-Cid, 1986:423 

[with a query]; Salcedo-Martínez et al., 1988:83; González-González 

et al., 1996:219; Ramírez and Santelices, 1991:234; Mateo-Cid and 

Mendoza-González, 1992:21; Mendoza-González and Mateo-Cid, 

1992:17; Serviere-Zaragoza et al., 1993a:483; León-Tejera et al., 

1993:200; Mateo-Cid et al., 1993:47; Stout and Dreckmann, 1993:10; 

Mateo-Cid and Mendoza-González, 1994b:39; Mendoza-González et 

al., 1994:106; Mateo-Cid et al., 2000:64; Cruz-Ayala et al., 2001:191; 

CONANP, 2002:140; López et al., 2004:11; Mateo-Cid et al., 2006:51; 

Serviere-Zaragoza et al., 2007:10; Gabrielson, 2008:94–96, fig. 3 [type 

of Grateloupia versicolor]; Pacheco-Ruíz et al., 2008:207; FernándezGarcía et al., 2011:62.

Grateloupia filicina sensu Taylor, 1945:204 [non Grateloupia filicina (J. V. 

Lamouroux) C. Agardh, 1822:223; see Dawson, 1954c:253].

Prionitis sternbergii sensu Kylin, 1941:10 [in part], pl. 2: figs. 6, 7; Dawson, 

1944a:282 [non Prionitis sternbergii (C. Agardh) J. Agardh, 1851:190; 

basionym: Sphaerococcus sternbergii C. Agardh, 1822:275; see Dawson, 1954a:256; Gabrielson, 2008:95].

Thalli of several erect narrow, compressed, branched fronds, 

up to 4.5 cm tall; dull purple to purple-green; arising from a 

discoid holdfast. Axes up to 4 mm wide; 300–500 μm thick; 

branched pinnately, subdichotomously, or irregularly, up to 4(–5) 

orders. Branches lanceolate, usually with short, lateral branchlets. Medulla dense, of branched filaments, mostly periclinally 
416 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 209. Habit variation in Grateloupia prolongata. A. JN-5167, US Alg. Coll.-159794. B. JN-5351, US Alg. Coll.-159796. C. JN-5898, 

US Alg. Coll.-159804.
NUMBER 96 • 417

aligned near the center; outer medulla of inflated stellate cells, 

grading into cortex of anticlinal filaments of 4–5 small cells.

Tetrasporangia 30–35 μm long, 10–12 μm wide, embedded 

in cortex and scattered over thallus surface. Cystocarps embedded and more or less aggregated or scattered over upper branch 

surfaces. Spermatangia not observed.

Habitat. On rocks or hard substrata, tidal platforms, and tidal pools; mid to low intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Bahía San Francisquito; Bahía Concepción to Cabeza Ballena; 

Mazatlán, Sinaloa to Jalisco. Eastern Pacific: Isla Magdalena 

(Bahía Magdalena) to Todos Santos, Baja California Sur; Isla San 

Benedicto (Islas Revillagigedo); Jalisco to Oaxaca; El Salvador; 

Chile. Western Pacific: China.

Type Locality. “St. Augustín in littore Mexicano 

Oceani Pacifici, Liebman” (J. Agardh, 1851); “St. Augustín, 

probably Oaxaca” (Dawson, 1954c), which is San Agustín, 

Bahías de Huatulco, Oaxaca, Pacific Mexico.

Remarks. A variety, Grateloupia versicolor var. 

prostrata E. Y. Dawson (1954a), was described from Isla San 

Benedicto (Islas Revillagigedo) and has been reported elsewhere 

in Pacific Mexico (Dawson, 1957a; Chávez-Barrear, 1972b; 

Huerta-Múzquiz and Garza-Barrientos, 1975) and El Salvador 

(Dawson, 1961c).

Grateloupia violacea (Setchell et N. L. Gardner) E. Y. Dawson

FIGURE 211

Schizymenia violacea Setchell et N. L. Gardner, 1924:786, pl. 25: figs. 37, 

38, pl. 87.

Grateloupia violacea (Setchell et N. L. Gardner) E. Y. Dawson, 1961a:200, 

pl. 8; 1961b:422; Norris, 1973:10; González-González et al., 1996:219; 

Pacheco-Ruíz and Zertuche-González, 2002:467; Pacheco-Ruíz et al., 

2008:207.

Schizymenia johnstonii Setchell et N. L. Gardner, 1924:786, pl. 88; Dawson, 

1944a:287.

Thalli of 1 or more membranous blades, rose red, slippery 

in texture, up to 230 cm long and up to 80 cm wide, arising 

above a short stipe; attached below by a small discoid holdfast. 

Blades broadly lanceolate to broadly ovate; 150–400 μm thick; 

simple, entire, or sometimes deeply cleft, occasionally lacerated 

or eroded; with undulate margins. Broad medulla of loosely interwoven slender filaments. Cortex relatively thin, of anticlinal 

filaments composed of 3–4 small ovoid cells.

Tetrasporangia cruciately divided, ellipsoidal, 28–32 μm 

long, 14–16 μm in diameter; scattered over blade surfaces above 

basal portion. Cystocarps embedded and bulging out from blade 

surface, nonostiolate; scattered over blade; carposporangial mass 

100–160 μm in diameter. Spermatangia unknown.

Habitat. On rocks; subtidal, 5–15 m depths.

Distribution. Gulf of California: Isla Patos (off 

north end of Isla Tiburón) to Bahía San Francisquito.

Type Locality. Isla San Esteban, Islas de la Cintura, Gulf of California, Mexico.

Remarks. Grateloupia violacea is a Gulf endemic, 

apparently restricted to the central Gulf. Recent collections suggest that G. violacea is an annual or perhaps a perennial with a 

persistent holdfast. Although occasional in distribution, where 

found, G. violacea can be abundant, reaching its largest sizes and 

population numbers in late spring.

Uncertain Record:

Grateloupia abreviata Kylin

Grateloupia abreviata Kylin, 1941:10; Mendoza-González and Mateo-Cid, 

1986:423 [with query].

Remarks. Grateloupia abreviata is generally considered 

to be conspecific with G. doryphora (Montagne) M. Howe (1914), 

e.g., by Abbott and Hollenberg (1976), but others have recognized 

it in Pacific Mexico from Michoacán (Dreckmann et al., 1990). Its 

reported presence in the northern Gulf of California by MendozaGonzález and Mateo-Cid (1986, with a query) needs to be verified.

Uncertain Record:

Norrissia setchellii (Kylin) Balakrishnan

Grateloupia setchellii Kylin, 1941:10; Mendoza-González and Mateo-Cid, 

1986:432. 

Norrissia setchellii (Kylin) Balakrishnan, 1980:284.

Remarks. Specimens of Norrissia setchellii from Segundo Cerro Prieta, Bahía Kino (Mendoza-González and MateoCid, 1986, as “Grateloupia setchellii”) need further study to 

verify its presence in the northern Gulf of California.

Halymenia C. Agardh

Halymenia C. Agardh, 1817:xix.

Algae are erect, usually lubricous, with one or more simple, 

lobed or dichotomously to irregularly branched fronds, attached 

by a discoid holdfast. Multiaxial in structure, the medulla is 

FIGURE 210. Grateloupia versicolor: Habit (JN-5720, US Alg. 

Coll.-159814).
418 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

composed of loosely interwoven slender filaments, with a number of anticlinally directed filaments from one side of the cortex 

to the other and also some periclinally oriented filaments. Filaments may radiate from stellate or refractive (deeply staining) 

ganglionic cells in the outer medulla and inner cortex. The cortex 

is relatively thin (three to six cells) and consists of large subcortical cells, becoming progressively smaller to an outer layer of 

small cells.

Tetrasporangia are cruciately divided, embedded in the 

outer cortex, and scattered over the thallus surface. Gametophytes are monoecious or dioecious. Carpogonial branches and 

auxiliary cells are borne singly on separate branch systems, both 

surrounded by ampullary filaments that arise from inner cortical 

cells. The carposporophyte has an auxiliary cell that remains distinct at its base and is surrounded by a loose network of slender 

involucres branching to the third order, derived from elongation 

and expansion of the ampullary filaments (without contribution 

from medullary filaments), and an ostiole is usually present. Cystocarps are embedded and scattered over the thallus. Spermatangia are borne in whitish sori at the cortical layer surface.

Currently, Halymenia is represented by five species in the 

northern Gulf of California.

KEY TO THE SPECIES OF HALYMENIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli composed of several stipitate, linear to lanceolate blades; simple or 1–2 times dichotomously branched; with acute 

or bifurcate apices; generally less than 1.5 cm wide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. bifida

1b. Thalli obovate to broadly lanceolate foliose blades; not dichotomously branched; greater than 1.5 cm wide (wider than 

the above species) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

FIGURE 211. Grateloupia violacea: A. Habit (JN-3053, US Alg. Coll.-159831). B. Transection showing a relatively wide medulla of sparse, 

irregularly oriented filaments, and a thin cortex, bearing a tetrasporangium (JN-3053-III, US Alg. Coll. microscope slide 4332). C. Transection 

through a cystocarp showing the basal fusion cell and involucres derived from medullary and ampullary filaments (JN-3053-IX, US Alg. Coll. 

microscope slide 4521). 
NUMBER 96 • 419

2a. Thalli of several broadly lanceolate, sometimes falcate blades; cystocarps with prominent ostiole; blades 400–500 μm 

thick and tall (20 cm or more) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. californica

2b. Blades obovate to broadly lanceolate or elliptical, orbicular, or reniform; cystocarps with inconspicuous ostioles; blades 

thinner, less than 400 μm thick, and typically less than 20 cm tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Blades obovate to lanceolate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. gardneri

3b. Blades elliptical, orbicular (wider than tall), or reniform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Blades nearly sessile (only a very short “peg” to attachment disc); blades broader than tall; carposporangia large, 

20–30 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . H. megaspora

4b. Blades above a short stipe; carposporangia smaller, 9–12 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . H. actinophysa

Halymenia actinophysa M. Howe

FIGURE 212

Halymenia actinophysa M. Howe, 1911:509, pl. 34; Dawson, 1944a:277; 

Taylor, 1945:206 [in part]; Dawson, 1954c [in part]:273, pl. 4: figs. 

29–34, pl. 15: figs. 59, 60, pl. 16: fig. 61; 1961b:423; 1966a:20; 

Abbott, 1967a:144; L. Aguilar-Rosas et al., 2000:130; CONANP, 

2002:140; Pacheco-Ruíz and Zertuche-González, 2002:467; MateoCid et al., 2006:55; Pacheco-Ruíz et al., 2008:207; Hernández-Kantún 

et al., 2009:248, figs. 1–12, tbls. 1–3; Bernecker, 2009:CD-Rom p. 63; 

Fernández-García et al., 2011:62.

Sebdenia actinophysa (M. Howe) Soler-Onís in de Jong, 1998:114, nom. illeg.; Serviere-Zaragoza et al., 2007:11; Littler and Littler, 2010.

Halymenia refugiensis E. Y. Dawson, 1944a:278 [with a generic query], pl. 

44: figs. 2, 3; Littler and Littler, 2010; Fernández-García et al., 2011:62.

Algae of 1 or more membranous, usually lubricous blades, 

light to dull rose red in color, arising from a small stipe; attached 

by a small discoid holdfast. Blades elliptical or irregularly orbicular, 4–12(–30) cm tall, 4–10(–20) cm wide; (50–)150–300 

μm thick in transection; margins simple or sinuate or irregularly 

dentate or lacerate. Medulla of anticlinal, sparingly branched filaments, occasionally with a few irregularly placed periclinal filaments. Medullary filaments, 7–19(–24) μm in diameter, 135–240 

μm long, arising from capituliform (stellate) cells of the subcortical layer. Ganglioid (stellate) cells with dense refractive contents. 

Inner cortex of spherical cells, 8–15 μm in diameter; subcortex 

of capituliform (“stellate”) cells with up to 8 stout filamentous 

arms radiating out. Outer cortex thin, of 1–2 cell layers; outermost cells 5–8 μm in diameter.

Tetrasporangia cruciately divided, ovoid to subspherical, 

9–14 μm in diameter; embedded in outer cortex, scattered over 

blade. Gonimoblast is “pedicellate” on elongated auxiliary cell. 

Cystocarps 100–180 μm in diameter, embedded and scattered 

over thallus; carposporangia 6–12 μm in diameter, in a compact, 

subspherical mass, surrounded by slender involucral filaments derived from elongated ampullary filament cells, inconspicuously ostiolate. Spermatangia developed by division of outer cortical cells.

Habitat. Occasional on rocks; subtidal, down to 

25 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to La Paz. Eastern Pacific: Isla Clarión and Isla Socorro (Islas 

Revillagigedo); Costa Rica; Panama. Central Pacific: Hawaiian 

Islands (Abbott, 1999).

Type Locality. La Paz, Baja California Sur, Gulf of 

California, Mexico.

Remarks. The internal structure of Gulf Halymenia 

actinophysa, seen in transection, has characteristic large, subcortical capituliform cells (“arachnoid” or “stellate ganglia” of 

Dawson, 1954c, and “mace-like” of Abbott, 1999).

There has been a difference of opinion as to the generic 

placement of Halymenia actinophysa. Soler-Onís (in [de] Jong, 

1998:114) proposed the transfer of H. actinophysa to Sebdenia, but since the basionym was not cited, that combination was 

invalid. However, recent morphological studies of HernándezKantún et al. (2009) of Halymenia actinophysa collected in the 

vicinity of La Paz (type locality) included reproductive specimens that revealed characteristics that confirm it should be 

included in Halymenia. Smaller, thicker specimens of H. actinophysa (4–10 cm tall, 4–9 cm wide, and 150–300 μm thick) 

from the southern Gulf were elucidated by Hernández-Kantún 

et al. (2009). Larger and thinner specimens (up to 30 cm tall, to 

20 cm wide, and 70–130(–220) μm thick) that were referred to 

H. actinophysa by Dawson (1954c) and Norris (1975, US Alg. 

Coll.) should be morphologically and molecularly reinvestigated 

to work out their taxonomic status. Their difference in thickness could represent phenotypic or habitat variation or could be 

an artifact of air-drying and pressing versus freshly collected or 

liquid-preserved specimens or could possibly reflect differences 

in different parts of the blades where sections were made or may 

possibly represent another taxon.

Another species also described from the Gulf of California, 

Halymenia refugiensis E. Y. Dawson (1944a), was considered 

to be conspecific with H. actinophysa by Dawson (1954c; Abbott, 1967a). More recently, Littler and Littler (2010) recognized 

H. refugiensis as a distinct species when reporting it from Pacific 

Panama. The taxonomic status of northern Gulf H. refugiensis

(type locality: Puerto Refugio, Isla Ángel de la Guarda) should be 

reinvestigated and tested in comparisons with the southern Gulf 

H. actinophysa.

Halymenia bifida E. Y. Dawson

Halymenia bifida E. Y. Dawson, 1954c:269, pl. 2, figs. 19–21, pl. 12, fig. 

56; 1961b:423; 1966a:27; 1966b:59; Mateo-Cid et al., 2006:52; 

Hernández-Kantún et al., 2009:249, 253: tbls. 1, 3.

Algae composed of several lanceolate, membranous stipitate blades, up to 8 cm tall, 4–13 mm wide, simple or dichotomously branched once or twice, 150–260 μm thick; arising 

from a short, slender, compressed, simple or branched stipe; 

attached by a small discoid holdfast. Blade margins entire 
420 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

or occasionally sparsely beset with short pinnate bladelets, 

1–2 mm long; apices acute, usually bifurcate; lowermost portion cuneate above stipe. Medulla of sparse, branched filaments 

(4–5 μm in diameter), irregularly and loosely cross from one 

side to the other, with some stellate or arachnoid cells adjoining the subcortex. Inner cortex of 2 layers of large, rotund 

cells, 9–16 μm in diameter. Outer cortex 1 layer of ovoid cells, 

5–7 μm in diameter.

Tetrasporangia cruciately divided, ovoid, 15–18 μm long; 

borne in cortex, scattered over blade surfaces. Cystocarps 100–

150 μm in diameter, surrounded by a loose network of involucres derived from elongation of the ampullary filament cells, 

embedded and scattered over thallus. Spermatangia unknown.

Habitat. On rocks, lowermost intertidal to subtidal; 

dredged from 8–19 m depths.

Distribution. Gulf of California: Punta Pelícano 

(vicinity of Puerto Peñasco); Punta Los Frailes; Bahía de San Lucas.

Type Locality. Punta Los Frailes, Baja California 

Sur, Gulf of California, Mexico.

Halymenia californica G. M. Smith et Hollenberg

Halymenia californica G. M. Smith et Hollenberg, 1943:216, figs. 18, 19; 

Smith, 1944:243, pl. 54: fig.6, pl. 55: fig. 4; Dawson, 1954c:270, 

pl. 13: fig. 57; 1961b:423; Hollenberg and Abbott, 1966:70; Abbott, 1967a:140, fig. 13; Abbott and Hollenberg, 1976:425, fig. 

378; L. Aguilar-Rosas, 1981:93; Anaya-Reyna and RiosmenaFIGURE 212. Halymenia actinophysa: A. Habit (JN-5137, US Alg. Coll.-159936). B–D. Squash preparations of female gametophyte: B. Ganglionic cell and developing ampulla. C. Young ampulla. D. Elongated ampullary filaments around carposporophyte (B–D, JN-4501c, US Alg. 

Coll. microscope slide 4399).
NUMBER 96 • 421

Rodríguez, 1996:864, tbl. 1; CONANP, 2002:140; HernándezKantún et al., 2009:249, 253: tbls. 1, 3; Fernández-García et al., 

2011:62.

Halymenia abyssicola E. Y. Dawson, 1944a:278 [with generic query]; 

1954c:271, pl. 3: figs. 22–25; 1961b:423; Fernández-García et al., 

2011:62.

Halymenia actinophysa sensu Dawson, 1954c:273 [in part; non Halymenia

actinophysa M. Howe, 1911:509].

Thalli of usually 1 (rarely more) membranous blade, up to 30 

cm tall, to 18 cm wide; dark rose red in color; arising from a short, 

broad stipe; attached by a discoid holdfast. Blades broadly lanceolate, sometimes falcate, 400–500 μm thick; margins entire; base cuneate. Medulla traversed by many slender anticlinal filaments from 

one side to the other and also contains some loosely arranged periclinal filaments (2–4 μm in diameter). Outer cortex of branched 

anticlinal filaments, 3–4 cells long; inner cortex and outer medulla 

of 2–4 layers of periclinal irregularly shaped filaments.

Tetrasporangia cruciately divided, elongate, 22–25 μm long, 

12–14 μm in diameter; borne in cortex, scattered over thallus 

surface. Cystocarps hemispherical, ostiolate; scattered throughout blade. Spermatangia unknown in Gulf material.

Habitat. On rocks; subtidal, 5–30 m depths.

Distribution. Gulf of California: Isla San Esteban; 

Isla Tiburón; Bahía de Loreto to Isla Partida (off north end of Isla 

Espíritu Santo); Cabo Pulmo to Punta Los Frailes. Eastern Pacific: 

northern British Columbia to central Baja California; Panama.

Type Locality. Moss Beach, San Mateo County, 

central California, USA.

Remarks. In the Gulf of California, Halymenia californica is found in the northern Gulf from Islas de la Cintura 

and in the southern Gulf from Isla Partida (off north end of Isla 

Espíritu Santo) to Punta Los Frailes.

Halymenia gardneri (Kylin) P. G. Parkinson

Aeodes gardneri Kylin, 1925:17, fig. 7a; Smith, 1944:241, pl. 54: figs. 4, 5.

Halymenia gardneri (Kylin) P. G. Parkinson, 1980:12; Lindstrom, 1986:532; 

Scagel et al., 1989:192; Stewart, 1991:92; Spalding et al., 2003:277; 

Pacheco-Ruíz et al., 2008:208.

Algae foliose, of 1 or more obovate to lanceolate, usually 

undivided, blades, bright cherry red in color, central California 

sizes up to 50 cm tall and to 25 cm wide (Smith, 1944; note that 

sizes were not reported for northern Gulf specimens by PachecoRuíz et al., 2008); arising above a discoid holdfast. Medulla of 

interwoven filaments. Cortex of 3–6 layers of similar-sized cells.

Reproductive structures not reported for northern Gulf material. In California specimens, cystocarps loosely surrounded by 

a few sterile filaments, ostiolate (after Kylin, 1925; Smith, 1944, 

1969).

Habitat. On rocks; subtidal.

Distribution. Gulf of California: Bahía de Los 

Ángeles. Eastern Pacific: southern British Columbia to southern 

California.

Type Locality. Whidbey Island (“Whidby”), Island County, Puget Sound, Washington, USA.

Remarks. Halymenia gardneri has been reported 

from Bahía de Los Ángeles by Pacheco-Ruíz et al. (2008). Since 

I have not seen their specimens, the description of the species is 

based on Smith (1944).

Halymenia megaspora E. Y. Dawson

FIGURE 213

Halymenia megaspora E. Y. Dawson, 1954c:272, pl. 3: figs. 26 [type specimen], 27, 28, pl. 14: fig. 58; Dawson, 1961b:423; González-González 

et al., 1996:223; Hernández-Kantún et al., 2009:249, 253: tbls. 1, 3.

Blades irregularly orbicular to reniform, membranous, lubricous, 10–15 cm high (wider than tall), 200–400 μm thick; 

lobed or lacerate; with smooth margins; cuneate in lower portion to a short stipe; attached below by a small discoid holdfast. 

Medulla sparse, of irregular, more or less anticlinal filaments 

(in transection, mostly from one side to the other); medullary 

filaments 6–7 μm in diameter, 150–163 μm long. Some stellate 

cells connected by periclinal filaments occur in the subcortex. 

Cortex of 3–4 layers of ovoid cells, 9–10 μm in diameter; outermost cortical cells slightly elongated, 10–12 μm long, 9–10 μm 

in diameter.

Tetrasporangia unknown. Cystocarps 100–150 μm in diameter, scattered over blade; carposporangia large, 20–30 μm in 

diameter (longer than wide), not angular, in a loose mass. Spermatangia unknown.

Habitat. On rock and sand bottom; subtidal, from 

8.0 to 18 m depths.

Distribution. Gulf of California: Canal de San 

Lorenzo (off southern end of Isla Espíritu Santo) to Bahía Los 

Frailes.

Type Locality. Rock-sand bottom, 8–15 m depths; 

Bahía Los Frailes (south side of Punta Los Frailes), Baja California Sur, Gulf of California, Mexico.

Remarks. Halymenia megaspora was described with 

its blade as “almost sessile” above a small fleshy peg and discoid attachment (Dawson, 1954c). Later Hernández-Kantún et 

al. (2009) in referring to this species, noted the base was cuneate above a short stipe. Halymenia megaspora is known in the 

southern Gulf, but it likely may be found in subtidal collections 

elsewhere in the Gulf. Although it was included as a synonym of 

W. templetonii (Abbott, 1967a, as “Halymenia templetonii”), it 

is currently considered a separate species. The type of H. megaspora E. Y. Dawson and additional collections are needed for 

critical study to clarify its taxonomic status.

Prionitis J. Agardh 

Prionitis J. Agardh, 1851:185.

Algae are erect and cartilaginous, with one or more axes 

that are terete throughout, or terete to slightly compressed in 

the lowermost portions and become compressed to flattened 

upward. These axes are pinnately, dichotomously, or irregularly 

branched often from the margins, and attached by a discoid holdfast. Branches are compressed or flat and can rebranch, often 
422 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 213. Halymenia megaspora: Habit (paratype: EYD-6904A, US Alg. Coll.-206130).
NUMBER 96 • 423

with a few to numerous proliferous branchlets. The medulla is 

composed of tightly interwoven periclinal filaments. The cortex 

is composed of dense, compacted cells, which become progressively smaller toward the thallus surface or have an abrupt size 

difference between the inner and outer cells.

Tetrasporangia are cruciately divided, scattered and embedded beneath the surface or borne in nemathecia. Carpogonial 

branches and auxiliary cells are formed singly in separate clusters 

of filaments (ampullae). Cystocarps are embedded in the thallus, 

surrounded by slender filaments, and have a carpostome. Spermatangia are borne in whitish sori on flattened branch surfaces.

Remarks. Wang et al. (2001) suggested that Prionitis was congeneric with Grateloupia. Whereas their analyses 

included the generitype, Prionitis lanceolata (Harvey) Harvey 

(1853; basionym: Gelidium lanceolata Harvey in Hooker and 

Arnott, 1833), their California specimens were from Pigeon 

Point, San Mateo County, not from the type locality (Monterey, 

Monterey County; Silva, 1979). [Note: if accepted, the name 

would be Grateloupia americana Kawaguchi et H.-W. Wang (in 

Wang et al., 2001) to avoid being a homonym of G. lanceolata

(Okamura) Kawaguchi (1997).] However, Gabrielson (2008) 

considered the proposed generic merger premature until morphological and molecular studies of Prionitis species from the 

Gulf of California, the Southeast Pacific, and eastern tropical 

Pacific can be completed. He also noted it is likely that there 

is more than one genus in the circumscribed Grateloupia sensu 

lato. There have been four species of Prionitis, one with two 

varieties, recorded for the northern Gulf of California. One additional species, Prionitis mexicana E. Y. Dawson (1944a), occurs in the southern Gulf from Cabeza Ballena to San Jose del 

Cabo (type locality) and Pacific Mexico from Baja California Sur 

(Dawson, 1954c, 1961b).

KEY TO THE SPECIES OF PRIONITIS IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli thin, up to 1 mm wide; branching irregular or dichotomous and irregular in mid portions . . . . . . . . . . . . . . . . 2

1b. Thalli mostly broader, 2.0–4.0 mm wide; taller; primary branching dichotomous to subdichotomous . . . . . . . . . . . . . 3

2a. Thalli up to 15 cm tall; subcylindrical to compressed, axes and branches wiry, mostly less than 1mm in diameter; primary 

branching irregular . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. delicatula

2b. Thalli shorter, up to 4 cm tall; compressed to flattened, axes and branches, narrow, 0.5–1.0 mm wide; branching primarily 

dichotomous (can become irregular in middle thallus) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. acroidalea

3a. Pinnate laterals on axes and branches, usually long, 10–15 mm in length . . . . . . . . . . . P. abbreviata var. guaymasensis

3b. Pinnate laterals on axes and branches shorter, mostly less than 3 mm long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

4a. Young branches spatulate; thalli usually 8 cm or less tall . . . . . . . . . . . . . . . . . . . . . . . . . . P. abbreviata var. abbreviata

4b. Young branches not spatulate; thalli taller, up to 12(–20) cm tall . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . P. cornea

Prionitis abbreviata Setchell et N. L. Gardner var. abbreviata

FIGURE 214A

Prionitis abbreviata Setchell et N. L. Gardner, 1924:785, pl. 25: fig. 

39, pl. 50b; Dawson, 1944a:283; Taylor, 1945:211; Dawson, 

1959a:25; 1961b:423; 1966a:20; Norris, 1973:19; HuertaMúzquiz, 1978:338; Ramírez, 1982:13, figs. 3, 20; Littler and Littler, 1981:tbl. 3, fig. 4; Huerta-Múzquiz and Mendoza-González, 

1985:50; Ramírez and Santelices, 1991:237; González-González 

et al., 1996:259; Riosmena-Rodríguez et al., 1998:27; Mateo-Cid 

et al., 2000:64; L. Aguilar-Rosas et al., 2000:130; Cruz-Ayala et 

al., 2001:191; CONANP, 2002:140; Pacheco-Ruíz and ZertucheGonzález, 2002:467; Mateo-Cid et al., 2006:51, 55.

Zanardinula abbreviata (Setchell et N. L. Gardner) G. De Toni, 1936b:[2]; 

Dawson, 1954c:279, pl. 19: fig. 64, pl. 20: figs. 65,–66; GonzálezGonzález et al., 1996:273; Pacheco-Ruíz et al., 2008:208.

Thalli of 1 or more branched flattened fronds, to 8 cm tall, 

often forming loose and irregularly shaped clumps, attached 

below by a small discoid holdfast. Fronds linear-lanceolate, 

cartilaginous, dark brownish red to black; axes to 4 mm wide; 

250–500 μm thick; branched irregularly, primary branches 

more or less dichotomous, ultimate segments spatulate with 

blunt apices. Secondary branching more or less pinnate and 

sometimes rebranched in a pinnate manner; mostly branched 

in 1 plane at irregular intervals along margins of primary 

branches. Adventitious foliar proliferations occasionally on 

faces of primary branches. Medulla of densely packed filaments. Cortex of inner 3 layers of rotund cells, 10–18 μm in 

diameter, grading into outer cortex of small cells, 3.5–5.0 μm 

in diameter, in anticlinal rows.

Tetrasporangia cruciately divided, 45–50 μm long, 9–12 

μm wide, borne in nemathecial sori, on secondary branchlets. 

Cystocarps up to 250 μm in diameter, embedded, ostiolate, aggregated on secondary branchlets, often bulging out of surface. 

Spermatangia unknown.

Habitat. On rocks, in tide pools, along ledges and 

crevices in slightly shaded areas; mid to lowermost intertidal.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena. Eastern Pacific: Galápagos Islands; Chile.

Type Locality. Isla San Esteban, Islas de la Cintura, Gulf of California, Mexico.

Remarks. Two varieties of Prionitis abbreviata are 

found in the Gulf of California. One, P. abbreviata var. abbreviata, has broader primary axes that are mostly dichotomously 

branched, with spatulate ultimate segments, similar to the type 

described by Setchell and Gardner (1924). The other variety, 

originally described as P. guaymasensis E. Y. Dawson (1944a), 

is P. abbreviata var. guaymasensis (E. Y. Dawson) E. Y. Dawson (1954c). This variety typically has narrower and longer, 
424 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

more abundant pinnate secondary lateral branchlets. There are 

some thalli that are intermediate between these two varieties, 

but in agreement with Dawson (1954c) I find it useful to recognize these two rather commonly occurring, usually distinct, 

varieties.

Prionitis abbreviata var. guaymasensis (E. Y. Dawson) 

E. Y. Dawson

FIGURE 214C,D

Prionitis guaymasensis E. Y. Dawson, 1944a:283, pl. 66: figs. 1, 2.

Prionitis abbreviata var. guaymasensis (E. Y. Dawson) E. Y. Dawson, 

1959a:25; 1961b:423; 1966a:20; González-González et al., 1996:259; 

Mateo-Cid et al., 2006:51.

Zanardinula guaymasensis (E. Y. Dawson) E. Y. Dawson, 1945e:93; 

González-González et al., 1996:273.

Zanardinula abbreviata var. guaymasensis (E. Y. Dawson) E. Y. Dawson, 

1954c:279; González-González et al., 1996:273.

Thalli cartilaginous, up to 7 cm tall; a single to few erect, narrow main axes; 1.5–2.0 mm wide, occasionally divided, usually 

in one plane; with numerous lateral, long secondary branchlets, 

FIGURE 214. Species of Prionitis. A. Prionitis abbreviata var. abbreviata: Habit (JN-7059, US Alg. Coll.-160707). B. Prionitis acroidalea: Habit 

(EYD-961, US Alg. Coll.-12842). C, D. Prionitis abbreviata var. guaymasensis: Habit variation (C, EYD-27341, US Alg. Coll.-40742; D, JN4051, US Alg. Coll.-160679).
NUMBER 96 • 425

5–18 mm long, 0.7–1.0 mm wide, narrowed at branch origin; with 

subacute apices (attenuated); thalli attached by discoid holdfast.

Habitat. On rocks, tidal platforms, and tide pools;

intertidal to shallow subtidal.

Distribution. Gulf of California: Puerto Peñasco 

to Guaymas; Isla San Pedro Nolasco; Puerto Refugio, Isla Ángel 

de la Guarda.

Type Locality. Punta San Pedro, about 41 km 

north of Guaymas, Sonora, Gulf of California, Mexico.

Prionitis acroidalea (Setchell et N. L. Gardner) E. Y. Dawson

FIGURE 214B

Grateloupia acroidalea Setchell et N. L. Gardner, 1924:781, pl. 26: figs. 45–

46; Dawson, 1944a:281.

Prionitis acroidalea (Setchell et N. L. Gardner) E. Y. Dawson, 1961a:424; 

Mendoza-González and Mateo-Cid, 1986:423 [with a query]; 

González-González et al., 1996:259.

Zanardinula acroidalea (Setchell et N. L. Gardner) E. Y. Dawson, 1954c:277, 

pl. 5: figs. 37–39 [from type of Prionitis kinoensis]; González-González 

et al., 1996:273.

Prionitis kinoensis E. Y. Dawson, 1944a:284, pl. 67: fig. 1; Taylor, 1945:210; 

Huerta-Múzquiz and Mendoza-González, 1985:50; GonzálezGonzález et al., 1996:260.

Zanardinula kinoensis (E. Y. Dawson) E. Y. Dawson, 1945e:94; GonzálezGonzález et al., 1996:273.

Algae forming short clumps, up to 4 cm tall; of few to several dark purple or greenish red compressed to flattened, cartilaginous, usually densely branched fronds; very narrow, up to 1 

mm wide (more or less uniform width throughout), 280–480 μm 

thick; attached by a small discoid holdfast. Branching mostly dichotomous and more or less divaricate, becoming irregular in 

middle portions; short secondary branchlets, 1–4 mm long; apices blunt, as wide as lower portion of branch or somewhat swollen in fertile thalli. Medulla of densely interwoven, compacted 

filaments. Cortex with an inner cortical layer of 2–3 large cells 

with “intercellular connections” (Dawson, 1954c: 278, pl. 5: fig. 

39, as Zanardinula acroidalea); outer cortical layer of anticlinal 

filaments composed of 5–6 small, pigmented cells.

Tetrasporangia 40–50 μm long, 8–13 μm wide, borne in nemathecial sori on secondary branchlets and terminal in branches. 

Cystocarps about 150 μm in diameter, ostiolate, embedded in 

branchlets and terminal portions. Spermatangia borne in sori, 

superficial on branchlets and terminal portions.

Habitat. On rocks, high to mid intertidal.

Distribution. Gulf of California: Bahía Kino to 

Guaymas; Isla Turner (off SE end of Isla Tiburón); Isla de Tortuga; Bahía de La Paz. Eastern Pacific: Galápagos Islands.

Type Locality. Upper intertidal; Isla de Tortuga, 

about 24.1 km [15 miles] northeast of Isla San Marcos, off 

Puerto Santa Rosalía, Baja California Sur, Gulf of California, 

Mexico.

Prionitis cornea (Okamura) E. Y. Dawson

Grateloupia cornea Okamura, 1913:63, pl. 118: figs. 1–11; Kawaguchi, 

1989:226, figs. 22–25; Wang et al., 2001:253, figs. 1–3.

Prionitis cornea (Okamura) E. Y. Dawson, 1958:71; Dawson et al., 

1960a:76, pl. 26: fig. 1; Dawson, 1961b:424; Dawson and Neushul, 

1966:177; Guzmán del Proó et al., 1972; Abbott and North, 1972:76; 

Abbott and Hollenberg, 1976:445, fig. 395; L. Aguilar-Rosas, 1981:93; 

Pacheco-Ruíz and Aguilar-Rosas, 1984:72, 77; Scagel et al., 1989:244; 

R. Aguilar-Rosas et al., 1990:125; R. Aguilar-Rosas and Aguilar-Rosas, 

1994:521; Perestenko, 1996:97, pl. 9: fig. 5; Riosmena-Rodríguez et 

al., 1998:27; Yoshida, 1998:729, fig. 3-57B; Schubert et al., 2006:1212, 

tbl. 1; Pacheco-Ruíz et al., 2008:208; Castaneda-Fernández de Lara et 

al., 2010:200, tbl. 1.

Carpopeltis cornea (Okamura) Okamura, 1936:553.

Zanardinula cornea (Okamura) E. Y. Dawson, 1954c:282, pl. 22: fig. 68.

Algae cartilaginous, up to 20 cm tall; of 1 or more narrow, 

strap-like main axes and branches, (1–)2 mm wide, more or less 

equal width throughout; 280–500 μm thick; primarily subdichotomously branched, up to 3–4 orders, at intervals of 1–4 cm, 

secondary branching pinnate, usually sparse from the margins, 

mostly 2–3 mm long (up to 10 mm long); apices slightly tapered; 

attached by spreading irregularly discoid holdfast. Medulla dense, 

of intertwined compact filaments, 4–10 μm in diameter; subcortex of irregular layers of rotund cells, to 25 μm in diameter, becoming progressively smaller to surface of small, pigmented cells.

Tetrasporangia cruciately divided, 30–43 μm long, 8–12 μm 

in diameter; in elongated elevated sori on ultimate branches. Cystocarps ostiolate, embedded within secondary branches and ultimate branchlets; carposporangial mass 130–150 μm in diameter, 

pedicellate above an auxiliary cell. Spermatangia not observed.

Habitat. On rocks; low intertidal.

Distribution. Gulf of California: Bahía de Los 

Ángeles; Mulegé. Eastern Pacific: Vancouver Island, British Columbia to Bahía Asuncíon, Baja California Sur; California Channel Islands; Islas Todos Santos (off Ensenada), Baja California. 

Western Pacific: Russia; China; Korea; Japan.

Type Locality. Kadzusa, Chiba Prefecture, Honshū

Island, Japan.

Remarks. Prionitis cornea has been reported in the 

northern Gulf from Bahia de Los Ángeles by Pacheco-Ruíz et al. 

(2008). Because I have not seen their specimens, the description 

is after Dawson (1954c).

Prionitis delicatula (W. R. Taylor) E. Y. Dawson

Prionitis filiformis var. delicatula W. R. Taylor, 1945:210, pl. 66: fig. 1.

Prionitis delicatula (W. R. Taylor) E. Y. Dawson, 1961a:424; 1966a:20; 

1966b:59; González-González et al., 1996:260; Mateo-Cid et al., 

2006:51.

Zanardinula filiformis f. delicatula (W. R. Taylor) E. Y. Dawson, 1945e:94; 

González-González et al., 1996:273.

Zanardinula delicatula (W. R. Taylor) E. Y. Dawson, 1954c:284; GonzálezGonzález et al., 1996:273.

Thalli bushy in appearance, of several branched, very narrow subcylindrical to compressed, sometimes flattened, axes, 

up to 15 cm tall; arising from a broad, discoid holdfast. Axes 

wiry, cartilaginous, brown to purple-black, up to 1 mm wide, 

180–300 μm thick, of more or less uniform width throughout; 

primary branching irregular; secondary branching more or less 
426 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

pinnate, branches relatively long, up to 3 cm, branching more 

dense in upper portions; branches tapering toward their basal 

portion; apices subacute. Medulla of densely packed filaments. 

Inner cortex of 2–3 irregular layers of rotund cells, to 12 μm in 

diameter; outer cortex of anticlinal rows of 3–4 small cells, to 4 

μm in diameter.

Reproductive material unknown.

Habitat. On rocks; mid intertidal.

Distribution. Gulf of California: Puerto Peñasco. 

Eastern Pacific: Isla San Benitos; Isla Cedros; Bahía Asuncion to 

Isla Magdalena (Bahía Magdalena), Baja California Sur.

Type Locality. On rocks; Bahía Sur (“South Bay”), 

Isla Cedros (“Isla Cerros”), off Baja California, Pacific Mexico.

Remarks. Dawson (1966a) in reporting Prionitis 

delicatula in the upper Gulf, noted the Puerto Peñasco specimens 

had fewer determinate laterals; and thalli of his specimens (US 

Alg. Coll.) were subcylindrical to slightly compressed, whereas 

those of Pacific Baja California Sur were flattened (cf. Taylor, 

1945: pl. 66: fig. 1).

Uncertain Record:

Prionitis australis (J. Agardh) J. Agardh

Prionitis australis (J. Agardh) J. Agardh, 1851:188; Mendoza-González and 

Mateo-Cid, 1986:432.

Remarks. Prionitis australis, a California species 

(Abbott and Hollenberg, 1976), was recorded from Segundo 

Cerro Prieta, Bahía Kino, by Mendoza-González and Mateo-Cid 

(1986) and González-González et al. (1996). Collection of more 

material, as well as reexamination of their specimens, will be 

helpful in order to verify its presence in the northern Gulf.

Tsengiaceae*

Tsengiaceae G. W. Saunders et Kraft, 2002:1259; Schneider and Wynne, 

2007:227.

Members are multiaxial in structure, with a filamentous medulla and a cortex of branched filaments forming cortical fascicles, without gland cells, and secondary pit connections between 

cells are lacking.

Life histories, where known, are an alternation of isomorphic generations. Tetrasporangia are scattered on fronds and 

regularly to irregularly cruciately divided. Gametophytes have 

a three-celled carpogonial branch, and connecting filaments are 

septate and branched, arising directly from an undivided fertilized carpogonium. Auxiliary cells are intercalary in cortical filaments and are diploidized (fertilized) by lateral fusion with a 

connecting filament, the connecting filaments often proceeding 

on to diploidize additional auxiliary cells. A gonimoblast is issued directly from the diploidized auxiliary cell. The carposporophyte develops thallus outward, with one to three gonimolobes.

* Contributed by Katina E. Bucher and James N. Norris. K. E. Bucher: 

Department of Botany, National Museum of Natural History, 

Smithsonian institution, Washington, D.C. 20013-7012, USA.

Remarks. A monotypic family, members of the Tsengiaceae strongly resemble those of the Nemastomataceae (Nemastomatales) in habit and vegetative structure. Saunders and 

Kraft (2002, as Halymeniales) provided morphological data, 

supported by molecular evidence, that Tsengia is closer to members of the Cryptonemiales and belonged in its own family.

Tsengia is now reported in the northern Gulf of California.

Tsengia K.-C. Fan et Y.-P. Fan

Tsengia K.-C. Fan et Y.-P. Fan, 1962:191; Womersley and Kraft, 1994:274.

Algae are erect, firm to soft and flaccid, and often lubricous 

or gelatinous. Species may be foliose, simple to divided, or laciniate, or others are terete or compressed and subdichotomously 

to irregularly branched. Thalli may also have many laterals or 

proliferations. Thalli are multiaxial with a medulla composed of 

entangled filaments. The cortex is formed by subdichotomously 

(to trichotomously) branched anticlinal filaments that are without gland cells or secondary pit connections. 

Life histories, where known, are triphasic, involving isomorphic tetrasporophytes and gametophytes (Umezaki, 1974, as 

Nemastoma nakamurae). Tetrasporangia are regularly to irregularly cruciate to obliquely divided; borne laterally off a cortical 

filament cell, scattered over the thalli. Gametophytes are monoecious or dioecious. Carpogonial branches 3(–4)-celled, borne 

on a supporting cell in the inner portions of cortical fascicles, 

with straight, curved, or coiled trichogynes. Auxiliary cells are 

borne in similar locations on inner cells of cortical fascicles. Fertilized carpogonia develop one to four connecting filaments that 

grow to an auxiliary cell (Umezaki, 1967). Connecting filaments 

may diploidize several auxiliary cells in succession (Dixon and 

Irvine, 1977b, as Platoma bairdii). Gonimoblasts arise directly 

from auxiliary cells and develop thallus outward. The carposporophyte is borne among the cortical filaments, with all of its cells 

(except the gonimoblast initial) developing into carposporangia. 

Spermatangia are developed from the outer cells of the cortical 

filaments (after Womersley and Kraft, 1994).

One species of Tsengia occurs in the northern Gulf of 

California.

Tsengia abbottiana (J. N. Norris et Bucher) J. N. Norris et 

Bucher, comb. nov.

FIGURES 215, 216A,B

Platoma abbottianum J. N. Norris et Bucher, 1977:157 [as “P. abbottiana”], 

figs. 1–9; González-González et al., 1996:248; Pacheco-Ruíz et al., 

2008:210; Gabriel et al., 2010:4, tbl. 1.

Algae erect foliose blades, up to 27 cm tall, flattened, rose 

red, gelatinous and slippery but firm in consistency; arising from 

a short stipe attached by a discoid holdfast, branching somewhat dichotomously to irregularly. Young blades often with 

forked blunt apices; blades thicken and expand, becoming irregularly lobed with age. Internally, blades composed of loosely 

aggregated filaments in a gelatinous matrix. Medulla consists 

of slender, septate, sparingly branched, longitudinally arranged 
NUMBER 96

• 427

FIGURE 215. Tsengia abbottiana: A. Habit; note 

stipe (arrow) (holotype of Platoma abbottiana, 

JN-5677, US Alg. Coll.-55677). B. Carpogonial 

branch (cb) and supporting cell (sc). C. Presumed 

fertilized carpogonium issuing connecting fila-

ments (cf) (B, C, JN-5677, US Alg. Coll. micro-

scope slide 1071).
428 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

filaments, 4.5–15 μm wide and to 56 μm in length, and with 

some X-shaped cells that issue rhizoidal filaments. Outer medullary filaments bear numerous laterals, which branch outward to 

form the cortex of dichotomously branched, 5–7 times, cortical fascicles. Inner cortical cells cylindrical, 9–15 μm wide and 

16.5–27.0 μm long, decreasing in size toward the surface; cortical surface cells tear shaped, 3–6 μm in diameter (Figure 216B). 

Gland cells absent.

Gametophytes apparently dioecious. Carpogonial branches 

3-celled, with a long, straight trichogyne, borne on a supporting 

cell (darkly staining with aniline blue) (Figure 215B) on inner 

dichotomies of cortical fascicles. Connecting filaments arise directly from a fertilized carpogonium (Figure 215C). Auxiliary 

cells intercalary, usually borne on separate cortical filaments 

from carpogonial branches, within inner dichotomies of cortical 

fascicles and indistinguishable from vegetative cells before fusion 

with a connecting filament, which results in the formation of a 

single gonimoblast initial by the auxiliary cell, generally opposite the site of fusion. Mature cystocarps spherical to irregular 

in shape, 130–195 μm in diameter, and immersed in the cortex. 

Carposporangia are spherical, to 9 μm in diameter. Tetrasporangia and spermatangia unknown.

Habitat. On rocks; subtidal, down to 20–25 m 

depths.

Distribution. Gulf of California: Isla Mejía and 

Puerto Refugio, Isla Ángel de la Guarda.

Type Locality. 23 m depth; in channel off SE end 

of Isla Mejía, northwest side of Puerto Refugio, Isla Ángel de la 

Guarda (Islas de la Cintura), Gulf of California, Mexico.

Remarks. The female reproductive features of

Platoma abbottianum differ from those of the genus Platoma

Schousboe ex F. Schmitz (1894) as it is currently defined (Masuda 

and Guiry, 1995a). Species of Platoma possess darkly staining 

“nutritive auxiliary” cells, borne to each side of the supporting 

cell of the carpogonial branch, and carpogonia may or may not 

divide (depending on species) after fertilization, and one or both 

of these derivatives fuse or pit connect with the adjacent nutritive 

auxiliary cells before sending out connecting filaments to effect 

FIGURE 216. A, B. Tsengia abbottiana: A. Detail of lower branching developed above stipe. B. Cortical filament (A, B drawn from holotype: 

JN-5677, US Alg. Coll.-55677). C. Predaea masonii: Habit of thick gelatinous blade with faint veins (after Dawson, 1961a: pl. 3, fig.1).
NUMBER 96 • 429

diploidization of the “generative” auxiliary cells. Platoma abbottianum does not have “nutritive auxiliary” cells associated with 

its carpogonial branch nor this postfertilization development and, 

consequently, needs to be transferred to a more appropriate genus.

The female gametophyte of P. abbottianum has a close anatomical affinity with two genera, Tsengia and Itonoa Masuda et 

Guiry (1995b), that are in two different orders. Both genera lack 

gland cells and lack darkly staining “nutritive auxiliary” cells on 

the supporting cell of their carpogonial branch and have connecting filaments issued directly from fertilized carpogonia. A key feature separating Tsengia and Itonoa is their life history: sporophytes 

and gametophytes are isomorphic in species of Tsengia, whereas 

those of Itonoa are heteromorphic, involving erect gametophytic 

fronds and a sporophyte that is either a crust or tuft of filaments 

(Masuda and Guiry, 1995b). However, since the tetrasporophyte 

of P. abbottianum is unknown, female reproductive morphology is 

used as a primary distinguishing feature. There are differences between the carpogonial branches; those of Itonoa contain a greater 

number of cells and have extraneous lateral branchlets, both sterile 

and/or fertile (can be compound), borne on it, whereas the carpogonial branch of P. abbottianum is three-celled, with a straight 

trichogyne, and does not have any extraneous cells or filaments 

attached, more akin to the carpogonial branch of Tsengia. Connecting filaments of P. abbottianum resemble those of Itonoa, in 

that the filaments branch before reaching the auxiliary cell, with 

one fork terminating at the auxiliary cell and the other continuing 

to lengthen, presumably forging ahead to the next auxiliary cell. 

Although connecting filaments of Tsengia do not fork just before 

auxiliary cells, they fuse laterally with auxiliary cells and then continue on, presumably to diploidize additional auxiliary cells. Vegetative X- shaped cells that occur in the medulla of Itonoa and P. 

abbottianum are also known in species of other genera [see Gabriel 

et al., 2010, Platoma cyclocolpum (Montagne) F. Schmitz (1894)], 

so their presence may not be a good character for generic distinction. Since the tetrasporophyte of P. abbottianum is unknown, the 

species is tentatively assigned to Tsengia on the basis of its unadorned three-celled carpogonial branch. Further studies, such as 

DNA sequence analysis, the discovery of the tetrasporophyte, or 

life history studies, will enable resolution of its generic placement.

Tsengia abbottiana is apparently rare in occurrence in the 

Gulf of California, thus far only known off the northern end of 

Isla Ángel de la Guarda in the central Gulf. It has been also reported in the South Pacific from Moorea, French Polynesia (Payri 

et al., 2000; N’Yeurt and Payri, 2010, as Platoma abbottianum).

Nemastomatales*

Nemastomatales Kylin, 1925:39 [as “Nemastomales”]; Saunders and Kraft, 

2002:1257.

Gametophytes are multiaxial in structure, with thalli of 

various shapes and are usually gelatinous or lubricous in texture. Thalli possess a medulla composed of loosely to densely 

arranged slender filaments and rhizoids. The cortex is composed 

of usually pseudodichotomously branched anticlinal cortical filaments and adventitious rhizoidal filaments, and there are no secondary pit connections (except in Schizymenia apoda (J. Agardh) 

J. Agardh, 1851). Gland cells are present in some members and 

absent in others.

Life histories, where known, are of heteromorphic tetrasporophytes and gametophytes. Tetrasporophytes are minute to expanding fleshy crusts or Acrochaetium-like filaments and produce 

zonately divided tetrasporangia. Carpogonial branches are (2–)3(–

5) cells long, and one family has additional dark staining “nutritive auxiliary” cells borne on the supporting cell of the carpogonial 

branch. After fertilization, the carpogonium either directly generates septate, branching, connecting filaments, or in members of 

one family, divides once, and one or both halves fuse or pit connect to the nutritive auxiliary cells and then produce connecting 

filaments. Connecting filaments grow to generative auxiliary cells 

to transfer the diploid nucleus. Generative auxiliary cells are intercalary in cortical filaments, usually located in cortical filaments 

separate from those bearing the carpogonial branches. Connecting 

filaments diploidize auxiliary cells by a lateral fusion and continue 

on or terminate at the auxiliary cell. Gonimoblast issued lateral or 

outward either from the auxiliary cell or from the connecting filament at its site of fusion with the auxiliary cell. Carposporophytes 

of one to three gonimolobes of carposporangia usually develop 

outward toward the thallus surface but develop inwardly in one 

genus, Adelophycus Kraft (in Womersley and Kraft, 1994), from 

Australia. Cystocarps are compact and with or without an ostiole. 

Spermatangia are scattered or in patches on cells near the thallus 

surface (after Saunders and Kraft, 2002.)

The order is represented by both of its families in the northern Gulf of California.

* Contributed by Katina E. Bucher and James N. Norris. K. E. Bucher: 

Department of Botany, National Museum of Natural History, 

Smithsonian institution, Washington, D.C. 20013-7012, USA.

KEY TO THE FAMILIES OF NEMASTOMATALES IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli soft and gelatinous; supporting cell of carpogonial branch without adjoining darkly staining “nutritive auxiliary” 

cells; connecting filaments issued directly from fertilized carpogonia . . . . . . . . . . . . . . . . . . . . . . . . . Nemastomataceae

1b. Thalli membranous (not gelatinous), may be slippery; supporting cell of carpogonial branch bearing adjoining, darkly 

staining “nutritive auxiliary” cells; carpogonia may or may not divide after fertilization, and one or both derivatives fuse 

or pit connect with nutritive auxiliary cell(s) before issuing connecting filaments . . . . . . . . . . . . . . . . . Schizymeniaceae
430 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Nemastomataceae

Nemastomataceae F. Schmitz in Engler, 1892:22, nom. cons; Schmitz and 

Hauptfleisch, 1897d:521 (both as ‘Nemastomaceae’).

Gymnophlaeaceae Kützing, 1843:389, nom. rej. [see Silva, 1993b:708].

Gametophytes are erect above a discoid base, soft and flaccid, often gelatinous, and may be either (1) foliose, compressed 

to flattened, and simple to divided or branched blades or (2) 

complanate to compressed and entire or lobed or (3) cylindrical 

and subdichotomously to irregularly branched. All are multiaxial in structure, with a medulla of loosely entangled or sometimes 

longitudinally aligned filaments and a more compact cortex of 

subdichotomously branched filaments with progressively smaller 

cells toward the blade surface. Adventitious rhizoidal filaments 

may be issued from medullary and cortical filaments. Some medullary filaments with X-shaped cells. Medullary and cortical filament cells are without secondary pit connections, and gland cells 

are lacking in most members but are present in some others. Millar and Guiry (1989) proposed the use of the term vesicular cells 

for structures that were earlier called “gland cells” or “secretory 

cells” as they have no known secretory function.

Life histories are mostly unknown, but heteromorphic 

phases have been reported. The heteromorphic sporophyte 

is filamentous or may be crustose. Tetrasporophytes, where 

known, produce zonately divided tetrasporangia. Monosporangia are reported in at least one species (Millar and Guiry, 1989). 

In this family, foliose or terete gametophytes produce carpogonial branches and auxiliary cells on separate cortical fascicles 

(nonprocarpic). The auxiliary cells are intercalary in the cortical 

filaments. After fertilization, the carpogonia directly issue connecting filaments that grow toward auxiliary cells, where they 

fuse, transferring the diploid nucleus. The gonimoblast develops outwardly toward the blade surface in most members, with 

nearly all of its cells forming carposporangia. Cystocarps are embedded within the thallus and consist of groups of carposporangia in various stages of maturity. Spermatangia are cut off from 

the outer cortical cells.

The Nemastomataceae is represented by one genus in the 

northern Gulf of California.

Predaea G. De Toni

Predaea G. De Toni, 1936b:[5].

Clarionea Setchell et N. L. Gardner, 1930:174, nom. illeg. [non Clarionea 

Lagasca ex A. P. de Candolle, 1812:65].

Algae are blade-like, ovoid, irregularly divided or variously 

lobed and soft and gelatinous in texture. The thallus is with or 

without a small stipe above a small discoid holdfast. The broad 

medulla is composed of loosely arranged slender filaments and 

rhizoidal filaments embedded in and traversing a matrix of soft 

clear jelly. The medullary filaments give rise to a short anticlinal 

layer of loosely arranged cortical fascicles that form the thallus 

surface. Cortical filaments are dichotomously to trichotomously 

branched and lack secondary pit connections between cells in adjacent cortical fascicles. Gland cells are present in some species, 

borne intercalary in cortical filaments.

Heteromorphic sporophytes (not known for all species) are 

acrochaetioid filaments known only from culture studies (Athanasiadis, 1988; Vergés et al., 2004) or crustose thalli that produce cruciately (Lemus and Ganesan, 1977) or zonately divided 

tetrasporangia or monosporangia (Millar and Guiry, 1989). Bisporangia (possibly propagules; Guiry and Guiry, 2008–2010) 

are reported on the outer cortical cells of the gametophyte of 

one species (Kajimura, 1987b). Gametophytes are monoecious 

or dioecious, carpogonial branches are (2–)3(–5)-celled and are 

typically borne on a cell near the basal dichotomy of inner cortical filaments. Auxiliary cells are intercalary and near the base of 

cortical filaments (separate from carpogonial branches). Modified vegetative cells adjacent to auxiliary cells bear short, simple 

to branched chains of small nutritive cells (cellules nourricieres) 

that form clusters near the auxiliary cells. The nutritive cellules 

near the auxiliary cells and cystocarps are a distinguishing character of this genus and are present before fertilization. One to 

many septate, branched connecting filaments arise directly from 

a fertilized carpogonium and grow the distance to diploidize the 

auxiliary cells. The gonimoblast initial usually originates from 

the connecting filament near the point where it fuses with the 

auxiliary cell, or in a few species the gonimoblast initial is issued by the auxiliary cell. Carposporophytes are ovoid to lobed 

and immersed in the cortex, scattered over the thallus. They lack 

a pericarp, involucral filaments, or an ostiole. All gonimoblast 

cells except the gonimoblast initial become carposporangia. 

Spermatangia are clustered at the apices of cortical filaments and 

produce subspherical spermatia.

Two species of Predaea are reported in the northern Gulf of 

California.

KEY TO THE GELATINOUS FOLIOSE SPECIES IN THE NORTHERN GULF OF CALIFORNIA: 

PREDAEA (NEMASTOMATACEAE), PLATOMA (SCHIZYMENIACEAE), AND TSENGIA (TSENGIACEAE)

Note: These Gulf of California species are distinguished from the other Gulf foliose reds 

by their soft, mucilaginous to gelatinous, and very lubricous texture.

1a. Mucilaginous blades with or without a stipe; cells adjacent to auxiliary cells without short chains of small nutritive 

cellules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Mucilaginous blades without a stipe; cells adjacent to auxiliary cells with short chains of small, nutritive cellules . . . . 3
NUMBER 96 • 431

2a. Mucilaginous blades, divided into portions above a distinct short stipe; younger blades somewhat dichotomously divided 

in upper portion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tsengia abbottiana

2b. Mucilaginous blades, broadly lobed; without a stipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Platoma fanii

3a. Mucilaginous blade with faint, broad, more or less opposite veins from a central vein; gland cells lacking; cortical cell 

shape linear to oblong . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Predaea masonii

3b. Mucilaginous blade lacking any evident venation; gland cells present, spherical; cortical cell shape spherical to ovoid

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Predaea japonica

Predaea japonica T. Yoshida

FIGURE 217

Predaea japonica T. Yoshida, 1980:69, figs. 1–4; Kajimura, 1990:530, figs. 

1–17; Yoshida, 1998:761.

Predaea masonii sensu Norris, 1975:332, pl. 15: fig. C; Norris and Bucher, 

1976:14, fig. 6c; Pacheco-Ruíz and Zertuche-González, 2002:468; 

Pacheco-Ruíz et al., 2008:209 [non Predaea masonii (Setchell et N. L. 

Gardner) G. De Toni, 1936b:[5].

Algae erect, compressed, gelatinous, deeply divided foliose 

blades (usually of 3–5 broadly rounded lobes), up to 23 cm in 

height, 15 cm wide; without a stipe. Cortical filaments of moniliform cells that become progressively smaller toward the surface; 

dichotomously branched, 3–5 times, cortex up to 100 μm thick; 

occasional unbranched rhizoidal filaments issued from cortical 

filaments. Outermost surface cells very small, about 2.7 μm in diameter. Gland cells spherical, 10–15(–22) μm in diameter, prominent, intercalary in cortical filaments, (2–)3–5 cell layers below 

surface. Medullary cells slender, 3.6–4.0 μm in diameter, of varying lengths, loosely arranged, infrequently branched, within gelatinous matrix.

FIGURE 217. Predaea japonica: A. Habit (JN-5300, US Alg. Coll.-160633). B. Gland cell intercalary in cortical filaments (JN-5607, US Alg. 

Coll. microscope slide-5296). C. Clusters of nutritive cellules borne on cortical cells on both sides of the auxiliary cell (arrow) (JN-5295, US Alg. 

Coll. microscope slide 5298).
432 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Sporophyte not known. Gametophytes monoecious or dioecious. Carpogonial branch 2-celled, borne off innermost cortical 

cells; shape of cells distinctive, urn-like basal cell, carpogonium 

with a pit connection to a wide based trichogyne (cf. Yoshida, 

1980: fig. 3). Auxiliary cells are usually borne in cortical filaments separate from carpogonial branches and are larger (10 μm 

in diameter) than adjacent cortical cells. Cells to either side of the 

auxiliary cell bear several simple to pinnately branched chains of 

small nutritive cells (subspherical, about 3 μm in diameter). Connecting filaments fuse with a side of an auxiliary cell, resulting in 

a bulge; this bulge then cuts off the gonimoblast initial that develops the carposporophyte. Spermatangial thalli have not been 

found in the Gulf of California (as described for P. japonica from 

Japan: spermatangia occur on ends of cortical filaments and can 

also arise on rhizoidal filaments that upturn into the cortex, a 

distinctive feature of this species; Kajimura, 1990).

Habitat. Rare; subtidal, down to 20 m depths.

Distribution. Gulf of California: Isla Ángel de 

la Guarda; Isla Estanque; Islas de Los Gemelos, Bahía de Los 

Ángeles. Western Pacific: Japan.

Type Locality. Mitsuse, near Cape Nomo, Nagasaki Prefecture, Kyūshū, Japan.

Remarks. Predaea japonica differs from P. masonii in 

having gland cells, a thinner cortex (up to 100 μm thick within the 

gelatinous matrix ), and in lacking any evident venation in the blade.

Predaea masonii (Setchell et N. L. Gardner) G. De Toni

FIGURE 216C

Clarionea masonii Setchell et N. L. Gardner, 1930:174, pl. 9: figs. 34–38; 

Serviere-Zaragoza et al., 2007:9.

Predaea masonii (Setchell et N. L. Gardner) G. De Toni, 1936b:[5]; Dawson, 1954a:335, pl. 2: figs. 1–6; 1961a:196, pl. 3: figs. 1–6; 1961b:427; 

Dawson and Neushul, 1966:177; Kraft and Abbott, 1971:200; Abbott 

and Hollenberg, 1976:481, fig. 427; Stewart and Stewart, 1984:144; 

Bula-Meyer, 1992:61, 64; González-González et al., 1996:259; ServiereZaragoza et al., 2007:11.

Blade-like thallus, complanate, mucilaginous, pale red, up 

to 15 cm tall and to 9 cm wide; without an evident stipe, attached below by a small, more or less discoid holdfast. Blades 

irregularly ovate, slightly lobed, often with a faint indication of 

broad, pinnate to seemingly opposite veins from a central axial 

vein; up to 8 mm thick (sometimes more) below and 1–3 mm 

thick in upper portions. Medulla of elongated branching filaments, 2.5–4.0 μm in diameter, traversing a clear, gelatinous matrix. Cortical filaments about 300 μm in length, branched, of 

linear to oblong-elliptical cells, about 4 μm in diameter by 8–16 

μm long; cells become progressively smaller outward, to 2.0 μm 

in diameter, toward thallus surface.

Tetrasporangial thalli unknown. Carpogonial branch 

2-celled. Auxiliary cells intercalary in inner cortical filaments, 

small-celled nutritive cellules on cells adjacent to auxiliary cells. 

Carposporangia roundish to irregular, carposporangial mass 

to 200 μm in diameter. Spermatangial thalli not seen in Gulf 

material.

Habitat. On rocks; subtidal, 4–30 m depths.

Distribution. Gulf of California: Isla Carmén 

(east of Loreto); Canal de San Lorenzo (off southern end of Isla 

Espíritu Santo). Eastern Pacific: Anacapa Island and Santa Catalina Island (California Channel Islands); Isla Guadalupe (off Baja 

California); Isla Clarión (Islas Revillagigedo).

Type Locality. Growing on a crustose coralline; 

Isla Clarión (Islas Revillagigedo), west of Colima, Pacific Mexico.

Remarks. The generitype Predaea masonii was described from Pacific Mexico. It is apparently rare in the Gulf of 

California, only known in the southern Gulf from a few specimens (Dawson, 1961a). New collections as well as those earlierreported specimens need to be studied in order to evaluate the 

taxonomic status and phylogenetics of P. masonii in the Gulf of 

California.

Dawson (1961a:198) found that a specimen identified as 

“Platoma tenuis” (W. R. Taylor, 10 April 1939; AHFH-2996, 

now UC) was not Platoma tenue M. Howe et W. R. Taylor 

(1931; now Predaea tenuis (M. Howe et W. R. Taylor) BulaMeyer in Gabriel et al. (2010) but was referable to Predaea, 

probably P. masonii. CONANP (2002) list “Predaea masonii” without comment from Bahía de Loreto; these specimens 

should be reexamined and may belong here or possibly be P. japonica. Predaea masonii has also been reported in the Atlantic 

from the Canary Islands (Haroun et al., 2002), Ghana (Lawson 

and John, 1987), and North Carolina and in the Caribbean 

(Schneider and Searles, 1991). Differences between Pacific 

Mexico Predaea masonii, the Atlanic P. tenuis (Howe et W. R. 

Taylor) Bula-Meyer (in Gabriel et al., 2010; Bula-Meyer, 1992), 

and P. japonica suggest these records should also be comparatively studied.

Schizymeniaceae

Schizymenieae F. Schmitz et Hauptfleisch, 1897f:522.

Schizymeniaceae (F. Schmitz et Hauptfleisch) Masuda et Guiry, 1995b:66.

Gametophytes are erect, with simple (unbranched) blades 

or branched blade-like thalli. In texture they may be either soft 

and gelatinous or slippery, membranous, and firm. Most genera are noncalcified, but one, Titanophora, is calcified. Internally, the medulla is composed of loosely arranged, entangled 

filaments, which are usually periclinally directed. The cortex 

is more compact, formed by anticlinal fascicles of branched 

cortical filaments; secondary pit connections between cells of 

adjacent cortical filaments are absent (with the exception of 

Schizymenia apoda, which has some secondary pit-connections 

linking inner cortical cells (Gabriel et al., 2011). Gland cells are 

found in many species.

Life histories are triphasic, involving an alternation of heteromorphic sporophytes and gametophytes. In Schizymenia, 

the crustose, noncalcified sporophyte, often referred to as the 

Haematocelis-phase, produces terminal, zonately divided tetrasporangia (Ardré, 1980; DeCew et al., 1992). In other genera the 

life history is not completely understood. Crustose sporophytes 
NUMBER 96 • 433

are also reported in Platoma (Masuda and Guiry, 1995a; Huisman, 1999), and Gabriel et al. (2010) indicated there are morphologically different crustose tetrasporangial stages [note: for 

alternative interpretation see Zuccarello and West, 2010].

Gametangial thalli may be monoecious or dioecious. Carpogonial branches are borne on the inner cells of cortical filaments, 

and generative auxiliary cells are borne in separate cortical filaments. Carpogonial branches are three-celled, with adjoining 

cortical cells on either side of the supporting cell modified to 

nutritive or subsidiary auxiliary cells that also stain densely with 

aniline blue. Upon fertilization, the carpogonium divides and 

fuses or develops secondary pit connections with one or more of 

the nutritive auxiliary cells borne on the supporting cell before 

issuing few to many secondary connecting filaments that grow to 

reach and transfer the diploid zygote nucleus to the generative 

auxiliary cells. Generative auxiliary cells produce a gonimoblast 

that develops outward and forms a compact carposporophyte. 

The mature cystocarp is loosely surrounded by elongated cortical cells (rudimentary involucres) and releases carposporangia 

through a surface pore. Spermatangia develop in pairs on outer 

cortical cells, forming superficial patches.

Remarks. At least one genus of the family, Schizymenia, has been shown to contain natural products with antiviral 

activity (Nakashima et al., 1987; Bourgougnon et al., 1996).

Two of the five genera presently included in the Schizymeniaceae are reported to occur in the northern Gulf of California.

KEY TO THE GENERA OF SCHIZYMENIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Blades lobed or divided; flaccid, soft, and gelatinous; medulla of loosely aggregated slender filaments; gland cells absent 

or intercalary in some cortical filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Platoma

1b. Blades entire or divided; membranous, firm in texture, sometimes more or less “leather-like”; medulla of relatively dense 

slender filaments; large gland cells terminal on some cortical filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . Schizymenia

Platoma Schousboe ex F. Schmitz

Platoma Schousboe ex F. Schmitz, 1894:627.

Gametophytes are erect or decumbent, soft, smooth, compressed gelatinous blades that may be foliose and lobed or divided 

or irregularly subdichotomously branched. They are attached to 

the substratum by a small, crustose holdfast. Blade margins are 

entire and may be ruffled or undulate or sometimes have marginal proliferations. Thalli are composed of filaments embedded 

within a gelatinous matrix. Medullary filaments are slender, septate, and loosely entwined, some X-shaped cells occur in some 

species. Cortical filaments are relatively more compact, with fascicles of branching anticlinal filaments composed of pigmented, 

progressively smaller cells outward. Gland cells are intercalary in 

some cortical filaments or absent.

A diploid, sporophytic crustose phase has been reported in 

life history studies (Gabriel et al., 2010). Culture studies have 

shown (1) carpospores that develop directly into erect, branched 

filaments, (2) carpospores that initially develop monostromatic 

crusts or multilayered pseudodiscs of loosely aggregated filaments, 

from which erect filamentous thalli were produced, and (3) direct 

development of carpospores to an apparently permanent, multistromatic crustose thallus with monostromatic margins (Gabriel 

et al., 2010). Gametophytes are monoecious or dioecious. The 

carpogonial branch is three-celled, borne on a cortical filament 

cell, with its supporting cell developing “nutritive auxiliary” cells 

before fertilization in some species or after fertilization in others. 

There are two kinds of auxiliary cells: “generative” auxiliary cells 

that are intercalary in a cortical filament and spatially separate 

from the carpogonial branches, and “nutritive” auxiliary cells that 

are distal on the supporting cell of the carpogonial branch. Postfertilization, the carpogonium (may or may not divide depending 

on species) fuses with one or both nutritive auxiliary cells and then 

issues connecting filaments that grow to the generative auxiliary 

cells in separate cortical filaments. Developing carposporophytes 

produce gonimolobes, which, when mature, consist almost entirely of carposporangia. Several contiguous cortical cells elongate 

to arch around the carposporophyte. Cystocarps are immersed 

and scattered over the thallus, with carpospores released through 

an obscure ostiole (carpostome) or a gap in the cortex. Spermatangia develop in groups on the surface of cortical cells.

Remarks. The conservation of the name Platoma

as being neuter gender (Athanasiadis, 2000; Compère, 2003), 

rather than feminine (Norris and Bucher, 1976), was approved 

(McNeill et al., 2006). Therefore, the spelling of species names, 

where necessary, is correctable.

There is currently one species described as a Platoma in the 

Gulf of California (see also “Key to the Gelatinous Foliose Species in the Northern Gulf of California” following Predaea).

Platoma? fanii E. Y. Dawson

Platoma fanii E. Y. Dawson, 1961a:197, pl. 5, pl. 6: figs. 1–6; 1961b:427; 

González-González et al., 1996:248.

Sarcodiotheca linearis sensu Guiry and Guiry, 2008–2010 [non Sarcodiotheca linearis Setchell et N. L. Gardner, 1937:80].

Algae erect, foliose, complanate, very gelatinous, pale rose; 

up to 8 cm tall by 14 cm wide and 800–1200 μm thick, irregularly 

lobed and partially divided. Medulla of sparse, little-branched, 

interwoven filaments, cells of medullary filaments 47–58 μm 

long by 4.5–12.0 μm in diameter. Cortex about 150–200 μm 

thick, of pigmented, dichotomously branched cortical filaments; 

cells of inner cortical filaments, 23–28 μm long by 7–11 μm in 

diameter; cortical cells becoming smaller outward; ultimate cells 

ovoid to elliptical, 3–4 μm diameter.

Tetrasporangia not known. Carpogonial branch borne 

on cortical filaments, three-celled, with a long, often coiled, 
434 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

trichogyne; connecting filaments, branched, septate, 4–5 μm in 

diameter. Auxiliary cells modified from intercalary cells of inner 

cortical region, 16–19 μm long by 11–16 μm in diameter. The 

gonimoblast develops from a diploidized auxiliary cell, often 

opposite the fusion site with the incoming connecting filament. 

The carposporophyte is initially broadly ovoid, sometimes later 

becoming slightly lobed, and usually with a “pedicel” (presumably the auxiliary cell and gonimoblast initial). Spermatangial 

thalli unknown.

Habitat. Growing on rock; subtidal, depths of 9–37 

m (Dawson, 1961a).

Distribution. Gulf of California: Isla San Esteban.

Type Locality. Isla San Esteban (Islas de la Cintura), Gulf of California, Mexico.

Remarks. An endemic species from the northern 

Gulf, Platoma fanii is still only known from the type material of 

two specimens. Species of Platoma have two kinds of auxiliary 

cells: auxiliary cells intercalary in cortical filaments and “nutritive auxiliary” cells borne distally on the supporting cell of the 

carpogonial branch. The described characteristics of the carpogonial branch of P. fanii with its lack of “nutritive auxiliary” 

cells suggest P. fanii does not belong in the genus Platoma, and 

may belong in Tsengia K.-C. Fan et Y.-P. Fan (1962) or Itonoa

Masuda et Guiry (1995b). It is uncertain if gametophytes and 

sporophytes of P. fanii are heteromorphic (Itonoa) or isomorphic 

(Tsengia). Although the internal anatomy and some reproductive 

characters of P. fanii (Dawson, 1961a, pl. 6: figs. 1–6) are similar 

to Tsengia abbottiana, the external morphology of P. fanii differs in that it has no stipe, lacks branching, and is broadly lobed. 

Recognizing its generic placement is problematic; for now, this 

species is reluctantly left in Platoma, until additional Gulf specimens are discovered for the morphological, developmental, and 

molecular analyses needed to elucidate its taxomomic status.

Another eastern Pacific specimen identified as “Platoma 

fanii” was recently reported in Pacific Panama (Littler and Littler, 2010; Fernández-García et al., 2011). Examination of 

liquid-preserved portions of short erect blades (M. & D. Littler69030, liquid-preserved; US Alg. Coll.) revealed tetrasporangia, 

about 6 μm in diameter. The tetrasporangial parent cell is a cortical cell borne toward the end of the cortical filament. Although 

this suggests the Pacific Panama material is probably a species of 

Tsengia, without female gametophytes its identification remains 

uncertain.

Schizymenia J. Agardh

Schizymenia J. Agardh, 1851:158.

Gametophytes are erect, with one or more flattened, membranous foliose blades, generally firm in texture, above an inconspicuous cylindrical stipe, which attaches to the substrate 

by a small discoid holdfast. Blades are ovoid to lanceolate and 

may be entire or divided. Thalli are multiaxial in structure, with 

a medulla composed of colorless, interwoven filaments. The 

cortex is composed of anticlinal fascicles of subdichotomously 

branched filaments whose cells become progressively smaller 

toward the surface. Gland cells are interspersed in the cortex, 

located terminally on cortical filaments, often conspicuous and 

numerous.

Life histories are triphasic but are not known in all species. 

Where known, the tetrasporophytes and gametophytes are heteromorphic. Culture studies of the generitype, S. dubyi (Chauvin 

ex Duby) J. Agardh (1851), by Ardré (1980) showed germinating 

carpospores to develop Haematocelis-like tetrasporangial crusts. 

Tetrasporangia are zonately to occasionally irregularly divided 

and are embedded in the cortex, scattered over the thallus surface. Gametophytes can be monoecious or dioecious. Carpogonial branches are three-celled, with the “nutritive auxiliary” cells 

(also darkly staining) adjoining the support cell. After fertilization, the carpogonium divides and fuses or pit-connects with one 

or more nutritive auxiliary cells that issue connecting filaments. 

The diploid nucleus is transferred by the connecting filaments to 

generative auxiliary cells; nearly all cells of the gonimoblasts become carposporangia. The cortical cells pit-connected to the generative auxiliary cells elongate and develop into a loose involucre 

around the carposporophyte. Cystocarps are globose, with a distinct carpostome, and develop in the cortex and protrude into the 

medulla. Spermatangia are cut off from outer cortical cells.

Remarks. Two species, Schizymenia johnstonii and 

S. violacea, originally described from the Gulf of California by 

Setchell and Gardner (1924) were later considered to be a single 

species by Dawson (1944a) as S. violacea. Subsequently, Dawson 

(1961a) recognized S. violacea to be a member of the genus Grateloupia, as G. violacea (Setchell et N. L. Gardner) E. Y. Dawson.

Crustose Haematocelis are known to be sporophytes in life 

histories of some Schizymenia species (Guiry and Guiry, 2013). 

Haematocelis zonalis E. Y. Dawson et Neushul (1966:176) was 

described from Anacapa Island (California Channel Islands) and 

Bahía Agua Verde (Baja California Sur) in the southern Gulf, but 

culture and genetic studies are needed to see if it is involved in 

the life history of Gulf Schizymenia.

Currently, there is one species of Schizymenia reported in 

the northern Gulf of California.

Schizymenia pacifica (Kylin) Kylin

FIGURE 218

Turnerella pacifica Kylin, 1925:21, fig. 10a–e; Kylin, 1930:38, figs. 25, 26.

Schizymenia pacifica (Kylin) Kylin, 1932:10; Kylin, 1941:17; Smith, 

1944:258, pl. 60: fig. 4, pl. 61: fig. 1; Dawson, 1961a:199, pl. 3: fig. 

7, pl. 7; 1961b:427; Abbott, 1967b:162, figs. 1–3; Abbott and North, 

1972:76; Norris, 1973:11; Abbott and Hollenberg, 1976:481, fig. 

426; Silva, 1979:321; Pacheco-Ruíz and Aguilar-Rosas, 1984:73, 77; 

Ramírez and Rojas, 1988:22, figs. 5, 6, 27-29; Scagel et al., 1989:258; 

Stewart, 1991:99; Ramírez and Santelices, 1991:277; GonzálezGonzález et al., 1996:269; Pacheco-Ruíz and Zertuche-González, 

2002:468; Spalding et al., 2003:277; Pacheco-Ruíz et al., 2008:210.

Sarcophyllis californica sensu Setchell and Gardner, 1903:354 [non Sarcophyllis californica J. Agardh, 1876:263, which is Dilsea californica

(J. Agardh) Kuntze, 1891:892].
NUMBER 96 • 435

Algae of 1 to several foliose blades, dull brownish red in 

color; up to 30 cm tall and (4–)12–20 cm wide, 250–500 μm 

thick; ovate to broadly lanceolate (usually longer than wide; occasionally broader than long), sometimes falcate; undivided, or 

sometimes divided or deeply split; margins mostly slightly undulate, or sometimes irregular; blades either above a short stipe, 

1.0–2.0 mm long, or expanding directly from a small discoid 

holdfast. Medulla of entangled, slender, branched filaments 

about 7–11 μm in diameter; mostly periclinal and fewer anticlinal, outward tending to be mostly anticlinal. Cortex compact, 

of anticlinal fascicles of short branched filaments of 6–8(–15) 

cells; inner cortex of highly granular cells, 8–10 μm in diameter, 

becoming progressively smaller toward surface; outer cortex of 

4–5 pigmented cells, terminal cortical cells may be slightly elongated. Darkly staining gland cells terminal on some cortical filaments, elongate, ovoid to pyriform, 20–40(–60) μm in length, 

10–20 μm in diameter.

Sporangial thalli not seen in Gulf material. Cystocarps 

about 150–210 μm in diameter; scattered, slightly bulging over 

the blade surface; embedded within thallus, of several gonimolobes; carposporangia 30–45 μm long, 15–20 μm in diameter; with carpostome at thallus surface to discharge carpospores. 

Spermatangia about 4–5 μm in diameter; superficial, covering 

upper portions of blade; spermatia about 2 μm in diameter.

FIGURE 218. Schizymenia pacifica: A. Habit (female gametophyte) (JN-5759, US Alg. Coll.-160898). B. Surface view showing gland cells in 

cortex and several carpostomes of cystocarps, the largest with carposporangia visible within (JN-5747c, US Alg. Coll. microscope slide 4524). 

C. Portion of transection showing elongate gland cells terminating cortical filaments (JN-5747, US Alg. Coll. microscope slide 4526).
436 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Habitat. On rocks, sometimes sand-covered rocks; 

mid intertidal to shallow subtidal, down to 5(–10) m depths.

Distribution. Gulf of California: Puerto Refugio, Isla Ángel de la Guarda (Islas de la Cintura); Bahía Willard 

(northwest of Bahía San Luis Gonzága); Bahía de Las Ánimas. 

Eastern Pacific: Aleutian Islands, Alaska to Isla Magdalena 

(northwestern side of Bahía Magdalena), Baja California Sur; 

central Chile.

Lectotype Locality. On pilings of dock; Friday 

Harbor, San Juan Island, San Juan Islands, San Juan County, 

Washington, USA.

Remarks. Schizymenia pacifica is known in the Gulf 

of California from only a few collections. It can be distinguished 

from the other Gulf foliose reds by its brown-reddish color and 

somewhat “leathery” texture in the field and by the presence of 

ovoid to long-elliptical gland cells in its cortex. Dawson (1961a) 

suggested a drift fragment found at Bahía Agua Dulce, Isla Tiburón, might also be S. pacifica.

Plocamiales

Plocamiales G. W. Saunders et Kraft, 1994:1260.

Algae of this order are uniaxial and may be autotrophic or 

parasitic.

Gametophytes and tetrasporophytes are isomorphic. Tetrasporangia are zonately divided and borne in stichidia. Female 

reproductive structures are procarpic, with a three-celled carpogonial branch borne on an intercalary cortical supporting cell. 

After presumed fertilization, the carpogonium fuses with the 

supporting cell, and the supporting cell then additionally functions as the auxiliary cell. A single outwardly directed gonimoblast initial is issued by the auxiliary cell and develops several 

gonimolobes, most cells of which (except for basal cells) differentiate into carposporangia. A carposporophyte nutritive system 

is developed by the modification of cortical cells that are pitconnected to the auxiliary cell, but there is no fusion between 

these cells and the developing carposporophyte.

One family of the Plocamiales, the Plocamiaceae, occurs in 

the Gulf of California.

Plocamiaceae

Plocamiaceae Kützing, 1843:442, 449.

The family consists of only two genera: Plocamium J. V. 

Lamouroux and Plocamiocolax Setchell. Plocamium is an erect, 

pigmented, free-living macroalga of various shades of red that 

has a firm thallus of compressed to flattened axes that branch 

from the margins, often in a zigzag manner as growth is ramisympodial and pectinate from axes margins. Species of Plocamium are uniaxial in structure, with each central axial filament 

cell surrounded by four periaxial cells (most evident only in 

transections of the upper portions of the thallus, becoming obscure below) that produce the pseudoparenchymatous anatomy. 

Carposporophytes have nonostiolate pericarps. The other genus, 

Plocamiocolax is an adelphoparasite on its host Plocamium.

Species of Plocamiocolax form whitish (lacking chlorophyll and 

phycobilin pigments), small globose to pulvinate clusters (usually less than 5 mm). Carposporophytes have ostiolate pericarps 

(Kugrens and Delivopoulos, 1986).

The Plocamiaceae is represented by one genus in the northern Gulf of California.

Plocamium J. V. Lamouroux

Plocamium J. V. Lamouroux, 1813:137.

Algae are erect, with several compressed to flattened axes 

that are repeatedly pectinately branched in a unilateral alternating series of 2 or more lateral branches. Several axes often form 

a clump of fronds that is attached to the substrate by a hapteralike holdfast or prostrate terete branches with discoid holdfasts. 

Primary branching is ramisympodial, with a regular pattern of 

pairs or series of three or more laterals (depending on species), 

distichously arranged along alternating sides of axes margins. 

The most distal branch of each lateral series may continue to 

grow and repeats the branching pattern that is characteristic for 

the species, whereas the lowermost branch of the series usually 

remains undivided. However, in at least one species, adventitious 

branchlets occur in addition to the basic determinate branching pattern. Margins are entire or serrate, and in certain species 

branchlets may be recurved. Thalli are uniaxial in structure, with 

each axial filament cell bearing four pericentral cells (first two 

are lateral, and the other two are transverse). The pericentral 

cells in turn produce the pseudoparenchymatous medulla of successively smaller cells outward that form a compact cortex.

Tetrasporangia are zonately divided, within simple or 

branched stichidia that are either derived from the conversion of 

ultimate branchlets or are adventitious laterals that form distinct 

clusters in axils of branches. Sexual thalli are dioecious. In female gametophytes, the carpogonial branch is three-celled, with 

the supporting cell functioning as the auxiliary cell (after fusion 

with the fertilized carpogonium). Cystocarps have a lobed gonimoblast that is surrounded by a nonostiolate pericarp formed 

by cortical cell divisions. Most gonimoblast cells develop into 

carposporangia. Cystocarps are either scattered on axes margins, 

sessile, on a terete pedicel, or in axils of branchlets. Spermatangia develop from parent cells and cover the ultimate branchlet 

surfaces or are on special spermatangial branchlets that form 

tufts in axils of branchlets.

Remarks. Plocamium is a diverse genus of more 

than 45 currently recognized species (Wynne, 2002; Saunders 

and Lehmkuhl, 2005) distributed primarily in temperate to subtropical waters. The most widely reported species of Plocamium, 

P. cartilagineum (Linnaeus) Dixon (1967), has generally been 

accepted with a broad species concept, showing much morphological variability and being worldwide in distribution. More 

recently, molecular sequence data of northeastern Atlantic “P. 

cartilagineum” (Saunders and Lehmkuhl, 2005) showed specimens within the broadly defined species included an assemblage 
NUMBER 96 • 437

of cryptic or unrecognized species. Among this assemblage they 

distinguished four taxa: P. cartilagineum sensu stricto, P. subtile

Kützing (1866), and two new species: P. nanum G. W. Saunders 

et Lehmkuhl (2005) and Plocamium maggsiae G. W. Saunders et 

Lehmkuhl (2005). Cremades et al. (2011: 129, figs. 1–10) clarified the types of Plocamium cartilagineum and found P. subtile

Kützing (1866) to be conspecific (Cremades et al., 2011: 131, 

figs.11–15). They also recognized two others, P. lyngbyanum

Kützing (1843) (Cremades et al., 2011: 134, figs. 29–51, 59) 

and P. raphelisianum P. J. L. Dangeard (1949; see also Cremades 

Ugarte et al., 2007), as being distinct from P. cartilagineum.

Natural product chemistry has been studied in some specimens of Plocamium (Faulkner, 1977; Fenical, 1983). Although 

all “Plocamium cartilagineum” tested contained a mixture of halogenated monoterpenes, there were also some differences in the 

natural products of the California specimens versus those analyzed from elsewhere. For example, North Atlantic specimens 

from the British coast of the English Channel (Faulkner, 1977:6) 

contained three compounds that were analogues of the compounds found in Pacific Coast (USA) specimens and one major 

new component that was not found in Pacific material (Stallard 

and Faulkner, 1974). Furthermore, there were differences between populations of “P. cartilagineum” in Santa Cruz (northern 

California) and La Jolla (southern California) (Faulkner, 1977). 

Together these studies revealed that the taxonomy of Plocamium

in the eastern Pacific needs to be critically studied.

Many of the Pacific and Australasia specimens referred to a 

broadly defined “P. cartilagineum” may represent morphologically similar but different entities, some of which may be undescribed species (Saunders and Lehmkuhl, 2005). One species of 

Plocamium is known in the Gulf of California. It is recognized as 

being distinct from those of the Pacific Coasts of California and 

Baja California and herein is described as new.

Plocamium katinae J. N. Norris, sp. nov.

FIGURE 219

Plocamium coccineum sensu Dawson, 1966a:23; González-González et al., 

1996:250 [in part; Gulf of California references only; non Plocamium 

coccineum Lyngbye, 1819:39].

Plocamium cartilagineum sensu Norris, 1985d:213; González-González et 

al., 1996:250 [in part; Gulf of California references only]; Mateo-Cid 

et al., 2006:52, 56 [non Plocamium cartilagineum (Linnaeus) Dixon, 

1967:58; basionym: Fucus cartilagineus Linnaeus, 1753:1161].

Latin Diagnosis. Thalli erectis ramosis molliter in unicum planum, saepe ramosis in uno piano ad rubeum, 

plerumque minus quam 5 cm alt; vel aliqua compressa axes 

tenues plerumque ad 500 μm latae (quibusdam 750 μm), saepe 

ramosi axes margine, discoidea appensa pronus implicuit holdfast ramis secundis stolonifera develop attachments, main prima 

sympodiales axium ramosa, secundarium et ramosa subquent 

in plus minusve regularibus exemplum, rami marginalis producta series (2–)3–4(–5) ramos marginibus lateribus alternatalternis ramis lateribus ad 3–4 ordinibus, ramorum singulorum 

ordinum gradatim ad apices latus, imo ramosa manet ramulus,

distal sublime in ramulis successive plures palmites series, distal 

maxime lateralis ramus saepe series indeterminata aucta iterum 

ramosis alternis regularem normam; ramuli ultimi determinata, 

recta vel leviter recurvata, acuta, apicibus attenuata. Stichidia 

tetrasporangial plerumque simplices et ramosa flendo turgiduli 

similem ramulus ultima (one apicem divisum visurus pars sterilis) 310–510 μm in longitudine 120–150 μm latus, non stichidia dense aggregatae in axillis sed lateralibus margin tollitur in 

superiorem partem ramulis vel terminales ramulus, plerumque 

breviter stipitati, 30–60 μm longa. Tetrasporangiis 35–45 μm 

longus de 20 μm diametro (forsan immatura, ut illi observanda 

nondum distincte zonate) duo ferri versus bene definitae stichidia. Thalli cystocarpic et spermatangial ignotum.

Algae erect, delicate (not cartilaginous), richly branched in 

1 plane, bright red in color, mostly less than 5(–7) cm in height; 

of 1 or more compressed, slender axes, mostly to 500 μm wide 

(some to 750 μm), repeatedly branched from opposite margins of 

axes, up to 3–4 orders; attached by discoid holdfast and entangled lowermost branches that develop secondary stoloniferous 

attachments. Main axes compressed, with primary branching 

ramisympodial; secondary and subsequent branching in a more 

or less regular pattern; marginal branches produced in a series of 

(2–)3–4(–5) branches to alternating sides. Lowermost branchlet 

of the lateral series (being the previous apex of the ramisympodial growing axis) remains unbranched and narrows to a tip; 

margins are smooth. The more distal branchlets of a lateral series 

are progressively more developed; the most distal branch of the 

lateral series often indeterminate and growing to repeat the regular alternate branching pattern. Ultimate branchlets determinate, 

straight or occasionally slightly recurved, tapered to acute apices.

Tetrasporangial stichidia extend in a series along the margins of branches, being derived from conversion of branchlets. 

Presumably only young tetrasporangial stichidia were observed 

as tetrasporangia were not yet zonately divided. Most stichidia 

were simple, resembling a slightly swollen ultimate branchlet; 

a few were apically bifurcated (see Figure 219C), 310–510 μm 

in length by 120–150 μm in width; stichidia usually on a short 

stalk, 30–60 μm long. Tetrasporangia 35–45 μm long, about 20 

μm in diameter (probably immature); aligned in two offset rows. 

Cystocarpic and spermatangial thalli unknown.

Habitat. On rocks, tidal platforms, and sides of tide 

pools and in crevices and drainage channels of shaded habitats; 

mid to low intertidal and shallow subtidal, down to 6 m depth.

Distribution. Gulf of California: Puerto Peñasco; 

Puerto Lobos to El Desemboque (Haxöl Iihom in the language 

of the Seri); Cabeza Ballena.

Type Locality. Mid intertidal; Cumpleaños Tide 

Pool on tidal platform, Playa Las Conchas (Playa Estación), 

Puerto Peñasco, Sonora, Gulf of California, Mexico.

Holotype. JN-3632A (US Alg. Type Coll.-160510), 

24 November 1972, Coll. J. N. Norris and K. E. Bucher; isotype 

(US Alg. Type Coll.-160511).

Paratypes. Sonora, Puerto Peñasco: Playa Las 

Conchas (Playa Estación) tidal platform, EYD-27484 (US Alg. 
438 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 219. Plocamium katinae J. N. Norris, sp. nov.: A. Holotype, habit (JN-3632a, US Alg. Coll.-160510). B, C. Upper portion of branches 

showing axis with regular alternating series of 3–4 lateral branchlets (B, JN-4163, US Alg. Coll.-217348; C, JN-3897, US Alg. Coll.-160514). 

D. Branch axis with tetrasporangial branchlets (JN-5916, US Alg. Coll. microscope slide 8682). E. Tetrasporangial branchlets (JN-5916, US 

Alg. Coll. microscope slide 8683).
NUMBER 96 • 439

Coll.-40818), Coll. A. E. Dennis, 29 June 1965; JN-2948 (US 

Alg. Coll.-160507), 29 April 1972, Coll. J. N. Norris; JN-3150

(US Alg. Coll.-160508 and -160509), Coll. J. N. Norris and K. 

E. Bucher, 11 July 1972. Sonora: Cumpleaños Tide Pool, Playa 

Las Conchas (Playa Estación): JN-3656 (US Alg. Coll.-160512), 

Coll. J. N. Norris and K. E. Bucher, 25 November 1972; JN-3897 

(US Alg. Coll.-160514), 15 April 1973, Coll. J. N. Norris and K. 

E. Bucher; JN-4163 (US Alg. Coll.-217348), 1 June 1973, Coll. 

J. N. Norris and W. Fenical; JN-4652 (US Alg. Coll.-160158), 4 

July 1973, Coll. J. N. Norris, K. E. Bucher, and E. Johansen. Sonora, Punta Pelícano, northwest of Puerto Peñasco: EYD-27277 

(US Alg. Coll.-40854), 6 April 1966, Coll. E. Y. Dawson; MM/

DSL-s.n. (US Alg. Coll.-163917), Coll. M. M. Littler and D. S. 

Littler, 5 March 1973; JN-5884 (US Alg. Coll.-160529), 21 June 

1974, Coll. J. N. Norris; JN-5072 (US Alg. Coll.-160523), Coll. 

N. McKibbin, 14 February 1974. Sonora, Puerto Lobos: JN5916 (tetrasporic), off north side of point, on rock outcropping, 

about 6 m depth, 17 February 1973, Coll. J. N. Norris and K. 

E. Bucher. Baja California Sur: JN-4119 (US Alg. Coll.-160515), 

Cabeza Ballena (vicinity of the exposed wreck of the Japanese 

ship, Inari Maru No. 10), 3 m depth, 2 January 1973, Coll. J. N. 

Norris, K. E. Bucher, and H. Sleeper.

Etymology. The species is named for Katina Elizabeth Bucher (National Museum of Natural History, Smithsonian 

Institution) in recognition of her contributions to our knowledge 

of the northern Gulf’s marine algae. It is with Katy that I have 

shared many adventures in pursuit of our seaweed interests, traveling through the desert and beaches and diving offshore on the 

reefs of Sonora, Baja California, and Baja California Sur and the 

islands (Islas de la Cintura) of the Gulf of California.

Remarks. Plocamium katinae, although apparently 

not a common species in the northern Gulf, is distinctive. Its 

bright red, compressed axes, with a regular branching pattern in 

one plane, make it easily recognizable among the Gulf’s algae. 

One specimen with undivided tetrasporangia was collected in 

February, although the rest of our specimens collected from November to February (once in July) were nonreproductive. Reproduction was previously unknown in Gulf of California specimens 

(Dawson, 1966a, as “P. coccineum”).

The Gulf of California P. katinae is distinct from the California and Pacific Baja California Plocamium pacificum Kylin (1925; 

G. M. Smith, 1944; =P. cartilagineum subsp. pacificum P. C. Silva, 

1979; =P. coccineum var. pacificum (Kylin) E. Y. Dawson, 1961a). 

The Pacific Coast of North America Plocamium pacificum (often 

identified as “P. cartilagineum,” e.g., Abbott and Hollenberg, 

1976) is a more robust, cartilaginous species and usually is much 

larger (up to 25 cm tall), with axis widths of 1.0–1.5 mm. The 

Gulf of California Plocamium katinae is more delicate, smaller 

and more compact overall, consistently shorter in height (usually 

less than 5 cm tall), and thinner in axial width, mostly 500 μm 

(occasionally to 750 μm) wide, and more finely branched, in an alternating series of (2–)3–4(–5). The one tetrasporophyte of P. katinae discovered had a limited number of immature tetrasporangial 

stichidia; they were mostly simple, in the position of branchlets 

in a lateral series, and none were found in clusters in the axils of 

branches. In P.pacificum, the stichidia are mostly compound.

Uncertain Record:

Plocamium violaceum Farlow

Plocamium violaceum Farlow, 1877:240; Mendoza-González and MateoCid, 1986:424; González-González et al., 1996:251 [in part, Gulf of 

California reports only].

Remarks. Described from central California, Plocamium violaceum is reported from Alaska to Pacific Baja California 

(Abbott and Hollenberg, 1976; Pacheco-Ruíz and Aguilar-Rosas, 

1984; Scagel et al., 1989), and Pacific Panama (Fernández-García 

et al., 2011) and Chile (Ramírez and Santelices, 1991). Specimens 

referred to “P. violaceum Farlow” by Mendoza-González and 

Mateo-Cid (1986) from Puerto Peñasco should be reexamined to 

verify its occurrence in the northern Gulf of California.

Excluded Species:

Plocamium pacificum Kylin

Plocamium pacificum sensu Dawson, 1945d:48 [in part; only Gulf of California specimens]; González-González et al., 1996:251 [in part; only Gulf 

of California references; non Plocamium pacificum Kylin, 1925:42].

Plocamium coccineum var. pacificum sensu Dawson, 1961a:220 [in part; 

only Gulf of California specimens]; 1961b:428 [in part; only Gulf of 

California references]; González-González et al., 1996:250 [in part; 

only Gulf of California references; non Plocamium coccineum var. pacificum (Kylin) E. Y. Dawson, 1961a:220].

Plocamium cartilagineum sensu González-González et al., 1996:250 [in 

part; Gulf of California references only; non Plocamium cartilagineum

(Linnaeus) Dixon, 1967:58; basionym: Fucus cartilagineus Linnaeus, 

1753:1161].

Remarks. Examination of northern Gulf of California specimens identified as “Plocamium pacificum” (US Alg. 

Coll.) has shown them to be the new species P. katinae, and 

the presence of P. pacificum in the northern Gulf is doubtful. 

Currently, P. pacificum is known on the Pacific coasts of North 

America from Alaska to Isla Magdalena, Baja California Sur 

(Smith, 1944, as P. pacificum; Dawson, 1961a, as P. coccineum

var. pacificum; Silva, 1979, as P. cartilagineum subsp. pacificum; 

Scagel et al., 1989, as P. cartilagineum; Withall and Saunders, 

2007, as P. pacificum), and Isla Clarión (Islas Revillagigedo) 

(Taylor, 1945, as P. pacificum), in Central America from Pacific 

Panama (Littler and Littler, 2010; Fernández-García et al., 2011, 

both as P. cartilagineum subsp. pacificum), and in South America 

from the Galápagos Islands (Taylor, 1945, as P. pacificum).

Sebdeniales

Sebdeniales Withall et G. W. Saunders, 2007:388.

Growth is multiaxial in members of this order, and thalli 

have a filamentous medulla surrounded by a pseudoparenchymatous cortex.

Life histories include isomorphic tetrasporophytes and gametophytes. Tetrasporangia are cruciately to irregularly divided. 
440 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Carpogonia and auxiliary cells develop in separate branch systems (nonprocarpic) and are not positioned in specialized ampullae. After diploidization, auxiliary cells produce a single 

gonimoblast initial that develops thallus outward.

The Sebdeniales is currently a monotypic order, with its 

single family, the Sebdeniaceae, occurring in the northern Gulf 

of California.

Sebdeniaceae

Sebdeniaceae Kylin, 1932:12.

Algae are erect or repent, terete to compressed, branched to 

foliose, and soft to firm in texture. Growth is multiaxial. The cortex 

is composed of layers of round to elongate cells, which become progressively smaller toward the thallus surface. Centrally, the medulla 

is composed of parallel to entangled filaments that grade outward 

to stellate or ganglioid cells that connect to inner cortical cells. 

Tetrasporophytes and gametophytes are isomorphic. Tetrasporangia are cruciately to irregularly cruciately divided (sometimes appearing zonate), produced laterally from outer cortical 

cells, and are scattered throughout the cortex or in nemathecia 

depending on the genus. Gametophytes are monoecious or dioecious. Female reproductive structures are nonprocarpic and 

lack ampullar structures for carpogonial branches or auxiliary 

cell branches. Carpogonial branches are three- to four-celled and 

borne laterally on or in unmodified cortical filaments separate 

from those bearing intercalary auxiliary cells. After fertilization, 

carpogonia of most species produce a number of connecting filaments that radiate out and fuse with auxiliary cells. A gonimoblast initial is issued directly from an auxiliary cell and develops 

toward the thallus surface to form the carposporophyte. The 

auxiliary fusion cell remains at the base of the developing carposporophyte. Some species have rudimentary pericarps. Compact lobes of carposporangia develop from all but the innermost 

gonimoblast cells. Cystocarps are embedded in the thallus, only 

slightly protuberant, and scattered or aggregated throughout the 

thallus. Spermatangia are hyaline, pyriform to subglobose, produced from outer cortical cells, and form superficial sori.

Remarks. Since the family was recognized on the 

basis of Sebdenia, two other genera have been described, Crassitegula C. W. Schneider, C. E. Lane et G. W. Saunders (2006) and 

Lesleigha Kraft et G. W. Saunders (2011). Kraft and Saunders 

(2011) also documented the existence of additional taxa, noting 

a higher diversity is likely to be found in this order, as well as 

additional species richness within Sebdenia.

The Sebdeniaceae is represented by one genus, Sebdenia, in 

the northern Gulf of California.

Sebdenia (J. Agardh) Berthold

Halymenia sect. Sebdenia J. Agardh, 1876:134.

Sebdenia (J. Agardh) Berthold, 1882a:530; Berthold, 1884:21; Hansen, 

1989:54–59.

Algae erect, terete and tubular to flattened and blade-like, 

the various morphologies arising above a small stipe that is 

attached by a small discoid or crustose holdfast. Cortex pseudoparenchymatous, of few to many layers of cells, cells becoming progressively smaller from inner to outer cortex; outermost 

cortical cells pigmented and slightly elongate. Medulla of loosely 

arranged, mostly longitudinal filaments (arms or rays), which 

radiate outward from stellate or ganglioid cells and connect to 

other filament cells; ganglioid cells with shorter filaments radiating outward. Dark staining “gland cells” (“conjunctor cells” 

of Gavio et al., 2005; “ray primordial” of Kraft and Saunders, 

2011) are borne occasionally on some cells of the inner cortex 

and medulla in some species.

Tetrasporangia are scattered in the outer cortex. Carpogonial 

branches are 3–4 celled and develop on inner cortical cells, separate 

from auxiliary cells, in otherwise unmodified cortical filaments. 

Fertilized carpogonia of most species directly produce connecting 

filaments that radiate out and fuse with auxiliary cells. Connecting 

filaments may terminate at the base of the auxiliary cell or may 

continue to grow and effect diploidizations of additional auxiliary 

cells (Hansen, 1989). Auxiliary cell often surrounded by nutritive 

cells. Cystocarps are embedded and protuberant as the chamber 

with the developing carposporophyte uplifts the thallus surface. 

Depending on the species, cystocarps are with or without an ostiole, some with a rudimentary ostiole (Hansen, 1989). 

There is one species of Sebdenia currently recognized in the 

Gulf of California.

Sebdenia flabellata (J. Agardh) P. G. Parkinson

FIGURE 220

Isymenia flabellata J. Agardh, 1899:62, 66.

Sebdenia flabellata (J. Agardh) P. G. Parkinson, 1980:12; Schneider and 

Wynne, 1991:473, fig. 1 (lectotype); Yoshida, 1998:796, fig. 3-71 C; 

Xia and Zhang, 1999:115, fig. 67, pl. 7: fig. 6; Pacheco-Ruíz et al., 

2008:210; Hernández-Kantún et al., 2009:249, tbl. 1; FernándezGarcía et al., 2011:64; Acleto O. and Zúñiga A., 2011:109, figs. 41–48.

Halymenia agardhii De Toni, 1905:1542 [new name; to avoid creating 

a homonym of Halymenia flabellata F. Schmitz, 1895:140]; Okamura, 1930:21, pl. 266: figs. 1–3; 1936:534; Taylor, 1945:205; Dawson, 1954c:268, pl. 11: fig. 54; Dawson et al., 1960a:20; Dawson, 

1961b:423; Mateo-Cid and Mendoza-González, 1992:21; ServiereZaragoza et al., 1993a:483; Pacheco-Ruíz and Zertuche-González, 

2002:467.

Sebdenia agardhii (De Toni) Codomier, 1972:747.

Halymenia polydactyla Børgesen, 1932a:122, fig. 10, pl. IV; Yamada, 

1938b:126, pl. 28.

Sebdenia polydactyla (Børgesen) M. S. Balakrishnan, 1961a:89; 1961b:212, 

figs. 28–41, pl. 6: figs. 1, 2; Norris and Bucher, 1976:14, figs. 11a–c, 

12a–c; Acleto O., 1980:11, figs. 14, 25–29; Hansen, 1989:58; Ramírez 

and Santelices, 1991:292; González-González et al., 1996:270; 

Pacheco-Ruíz et al., 2008:210.

Algae are subcylindrical to slightly compressed (more or 

less oval in transection), dichotomously branched in 1 plane, up 

to 21 cm tall, rose red to dark purple-red in color, elastic and 

tough in texture, with a smooth lubricous surface and attached 

below by a discoid holdfast. Branches are mostly 0.5–1.1 cm 

wide, occasionally 1.6(–2.3) cm broad below the branch forks, 
NUMBER 96 • 441

with blunt or broadly rounded apices. Small marginal proliferations are rarely present. Medulla composed of numerous stellate cells, each with a number of long, thin filaments (rays or 

arms) radiating outward. Stellate cells are dense in the outer 

medulla, markedly ganglioid, with centers 12–23 μm in diameter, and radiating, short filaments (to 30 μm long). In the inner 

medulla, the stellate cells are more loosely arranged and larger, 

with centers 18–40 μm in diameter, and narrow, straight radiating filaments 130–180(–300) μm long. Pigmented “gland-like” 

cells (ray primordia, conjunctor cells), about 10–30 μm long, 

are occasional on the stellate cells and filiform medullary filaments. Cortex pseudoparenchymatous and narrower, 4–5(–7) 

cells thick. Outer cortex is of small pigmented cells, 3–6 μm in 

diameter, 3.0–12.5 μm long, that grade into the larger and more 

loosely arranged unpigmented inner cells, 20–30 μm in diameter.

Tetrasporangia cruciately divided, spherical to vertically 

elongate, 13–18 μm in diameter, 20–31 μm long, scattered in the 

outer cortex. Gametophytes dioecious. Cystocarps 180–310 μm 

in diameter, scattered over middle portions of thallus. Cystocarps embedded, bulging out the cortex above and forming an 

arched wall of vertical rows of 5–7 cortical cells. The developing 

carposporophyte has a dense base, an irregularly shaped auxiliary fusion cell, and nutritive cells, and the stellate cells of the 

outer medulla appear to stretch around the developing carposporophyte, creating a rudimentary pericarp.

Habitat. On rocks; shallow subtidal, 3–23 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to Caleta Santa María (north of Santa Rosalía); Nayarit to 

Jalisco; Isla María Magdalena (Islas Marías; =Islas Tres Marías). 

Eastern Pacific: Isla Asunción, Baja California Sur; Panama; 

Peru. Western Pacific: Japan; China.

Type Locality. Guadeloupe, French West Indies, 

Lesser Antilles, Caribbean Sea.

Remarks. Although most have followed Børgesen 

(1932a) in recognizing the similarity of the western Atlantic Sebdenia flabellata (type locality: Guadeloupe, Caribbean Sea) and 

Indian Ocean S. polydactyla (type locality: Port Okha, Gujarat, 

India), Silva et al. (1996a) noted that their being conspecific 

needs to be tested by studying their respective type specimens. 

The Gulf of California specimens tentatively referred to S. flabellata should also be critically compared with the type materials to 

elucidate their relationships. The sulfated polysaccharides from 

the Indian Ocean Sebdenia flabellata exhibited antiviral activity 

(Ghosh et al., 2009, as “S. polydactyla”). It would be interesting 

to investigate those of the northern Gulf S. flabellata to test if 

they too exhibit similar properties.

FIGURE 220. Sebdenia flabellata: A. Habit (JN-5490, US Alg. Coll.-217352). B. Transection of cystocarp showing basal fusion cell (JN-4430, 

US Alg. Coll. microscope slide 4503). C. Transection through cortical and medullary layers showing pigmented gland cell (arrow) on a large 

stellate cell of the inner medulla (JN-3398, US Alg. Coll. microscope slide 4501).
442 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Rhodymeniales

Rhodymeniales F. Schmitz in Engler, 1892:19.

Algae are cylindrical to foliose and tubular, compressed, or 

flattened and simple or branched. Most are erect, although some 

may be low growing or prostrate or partly erect and partly prostrate. Thalli are multiaxial in construction and can be solid or 

hollow or with solid axes and hollow branches. In those that are 

solid throughout or partially solid, the medulla is pseudoparenchymatous, composed of large cells (never filamentous). The 

cortex is composed of small cells. In those that are hollow, the 

inner cortical cells are lined with a limited number of longitudinal filaments that border the mucilage-filled cavity.

Tetrasporophytes produce regular or irregular cruciately or 

tetrahedrally divided tetrasporangia or produce polysporangia 

within the cortex that are either scattered over the surface or in 

nemathecial sori in some members. Gametophytes are dioecious 

or monoecious. Carpogonial branches are either three- or fourcelled. The auxiliary cell is the terminal cell of two cells borne 

on the supporting cell of the carpogonial branch. After fertilization, gonimoblast filaments are produced outward from an 

auxiliary cell, with most of the cells developing into carposporangia. Spermatangia develop from outer cortical cells to form 

various-sized sori.

Four families of the Rhodymeniales are represented in the 

northern Gulf of California.

KEY TO THE FAMILIES OF RHODYMENIALES IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli solid throughout; medulla pseudoparenchymatous; cystocarps with well-developed and persistent tela arachnoidea . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Faucheaceae

1b. Thalli may be solid or hollow throughout or partly solid and partly hollow; cystocarps with tela arachnoidea–like filaments or lacking them . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Thalli may be solid centrally with pseudoparenchymatous medullary cells (filaments absent) or with solid stipe and centrally hollow, nonseptate branches without longitudinal filaments bordering the hollow cavity; tetrasporangia cruciately 

(or decussately) divided; cystocarps lacking tela arachnoidea. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rhodymeniaceae

2b. Thalli with centrally hollow branches divided into segments by septa; bordering the hollow cavity are longitudinal 

filaments lining inner cortical cells; tetrasporangia tetrahedrally (rarely cruciately) divided; cystocarps with or without 

spiderweb-like filaments (=tela arachnoidea). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Branches divided at consistent (regular) intervals into segments by septa (diaphragms) of a single cell layer; carpogonial 

branches 4-celled; some tela arachnoidea–like filaments in cystocarpic cavity; tetrasporangia scattered in cortex . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champiaceae

3b. Branches divided into irregularly (variably) sized segments by septa of multiple cell layers or irregular filamentous plugs; 

carpogonial branches 3-celled; tela arachnoidea filaments absent from cystocarpic cavity; tetrasporangia terminal on 

cortical cells in small sunken sori formed by invagination of the cortex . . . . . . . . . . . . . . . . . . . . . . . . . Lomentariaceae

Champiaceae

Champiaceae Kützing, 1843:438; Saunders et al., 1999:35.

Algae are cylindrical to compressed, regularly segmented 

fronds that are hollow and filled with a dilute mucilage. The 

primary axes and stipitate region may also be hollow or may 

be solid in some members. Branch cavities are divided into segments that are separated by monostromatic transverse septa 

(diaphragms) (except Dictyothamnion) and lined by multiple 

longitudinal filaments bearing secretory cells. Cortex of one to a 

few (four) cell layers. Thalli multiaxial in structure, with a group 

of apical cells at their tips.

Sporophytes produce tetrahedrally divided tetrasporangia, developed from cortical cells, scattered in the cortex of 

branches, and/or polysporangia are produced in some species 

of Gastroclonium. Gametophytes dioecious or monoecious. 

Female gametophytes are procarpic; carpogonial branches are 

four-celled, with the auxiliary cell fusing with other cells after 

fertilization. The gonimoblast is globular, with most of its cells 

becoming carposporangia; hemispherical, with carposporangia borne directly on the fusion cell; or radiating, with only its 

terminal cells producing carposporangia. The fusion cell is usually small and compact, with outlines of its component cells remaining discernible; however, in some members, the fusion cell 

is comparatively massive, and outlines of constituent cells are 

obscured. Cystocarps are large, subspherical, and protruding. 

Spermatangia are developed in superficial sori over outer cortical cells of branches.

Two genera of the Champiaceae are represented in the 

northern Gulf of California.

KEY TO THE GENERA OF CHAMPIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Fronds with solid, terete, simple to branched stipe and primary axes and hollow, cylindrical to compressed, segmented 

branches; pericarp without tela arachnoidea–like filaments surrounding carposporophyte . . . . . . . . . . . Gastroclonium

1b. Fronds without solid stipe or axes; hollow throughout, cylindrical to compressed, segmented axes and branches; pericarp 

with tela arachnoidea–like filaments surrounding carposporophyte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Champia
NUMBER 96 • 443

Champia Desvaux

Champia Desvaux, 1809:245.

Algae may be entirely erect, prostrate, or partly prostrate 

and erect and composed of terete, compressed, or flattened axes, 

depending on the species. Thalli are segmented and alternately or 

sometimes oppositely or irregularly branched. Growth is multiaxial, from a group of apical cells, and the thallus is attached 

by a discoid holdfast. Thalli are divided into hollow segments 

filled with a dilute mucilage, separated by septa (diaphragms) 

one cell layer thick at regular intervals and may or may not be 

constricted at the septa. The hollow cavities are bordered by a 

limited number of longitudinal filaments that bear secretory cells 

(gland cells), and connect with cells of the septa. The cortex is 

thin, 1–2(–3) cells thick, with an inner layer of large cells and an 

outer incomplete layer of small cells.

Tetrasporangia are tetrahedrally divided, often numerous, 

and scattered over upper portions of branches, transformed from 

cortical cells and protruding inward toward the hollow cavity. 

Two types of sporangial development have been reported: intercalary on cortical cells (Irvine and Guiry, 1983) and from a single 

division of a terminal cortical cell to produce a tetrasporangium 

(Ballantine and Lozada-Troche, 2008). Gametangial thalli are 

dioecious. Procarps develop in cortical layers and consist of a 

four-celled carpogonial branch and a single two-celled auxiliary 

cell branch. After fertilization, the gonimoblast develops outward from a fusion cell, and terminal cells of the gonimoblast 

produce carposporangia. Cystocarps have a well-developed pericarp and an ostiole. The pericarp has a filamentous inner lining, 

with inner cells that become stellate and spiderweb-like (resembling tela arachnoidea). Cystocarps are scattered and conspicuously protrude from their bearing branch. Spermatangia develop 

in superficial sori on branches, with spermatia borne subterminal 

on elongated parent cells issued from cortical cells.

Remarks. Species of Champia are widely reported in 

warm-temperate to tropical seas. Spore germination and frond 

development was reported by Boillot (1961). A triphasic life history was described for C. parvula by Steele and Thursby (1983), 

who also suggested that with its ease of maintenance in culture 

and relatively short life history (completed in six weeks), it could 

be used as a bioassay organism. It has also been used for studies 

on the genetics of red algae (Kehoe and van der Meer, 1990). The 

two different methods of tetrasporangia development are problematic, and its implication for possible generic separation needs 

to be further investigated (Ballantine and Lozada-Troche, 2008).

Of the three species in the Gulf of California, two were described from the northern Gulf, and a third, C. parvula, is reportedly widespread in distribution.

KEY TO THE SPECIES OF CHAMPIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Fronds cylindrical; of open, loose, segmented branches; mostly 1.0 mm or more in diameter (0.5–2.5 mm) . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. cf. parvula

1b. Fronds compressed; of somewhat open to dense, segmented branches; mostly less than 1.0 mm wide (0.6–0.9 mm in 

width) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Fronds erect; of somewhat open, distichously branched, strongly compressed branches; segments 600–1100 μm wide by 

200–350 μm high in transection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. disticha

2b. Fronds low growing (mostly repent or only partially erect); compact, dense mats of entangled, overlapping, slightly 

compressed branches (oval in transection); multifariously branched; segments about 900 μm wide by 500 μm high in 

transection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . C. caespitosa

Champia caespitosa E. Y. Dawson

FIGURE 221B

Champia caespitosa E. Y. Dawson, 1944a:311, pl. 46: figs. 3, 4; 1950d:341 

[in part; not including Champia parvula]; Levring, 1960:59; Dawson, 

1963a:468 [in part; only C. caespitosa specimens]; Ramírez and Santelices, 1991:294; González-González et al., 1996:190.

Algae forming low-growing, dense mats of repent to partially erect, entangled and often rhizoidally adjoined, overlapping branches, up to 2 cm tall. Thalli subterete in younger 

portions and slightly compressed in older portions, regularly 

constricted, hollow segments divided by septa 1 cell layer 

thick; segments oval in transection about 700–900 μm wide by 

450–500 μm high; branching multifarious; branches attached 

to other branches by numerous accessory holdfasts and to the 

substratum or other algae by several irregular, rhizoidal discs 

formed by elongation and division of surface cells. Branches 

originate primarily from internodal segments and possibly at 

septal nodes as well (Dawson, 1944a: pl. 46: fig. 3). Outer 

cortex a layer of elongated cortical cells, interspersed with 

smaller irregularly shaped cells; inner side of cortical cells occasionally with secretory cells and lined with longitudinal filaments bearing secretory cells.

Reproductive sporophytes and gametophytes not known.

Habitat. On rocky shore; epiphytic on other algae, 

such as Amphiroa, Digenea, and Centroceras; mid to low 

intertidal.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda, and Isla Estanque (Islas de la Cintura). 

Eastern Pacific: Chile.

Type Locality. Isla Estanque (Pond Island), off 

southeast end of Isla Ángel de la Guarda, Islas de la Cintura, 

Gulf of California, Mexico.

Remarks. Champia caespitosa is separated from Gulf 

C. parvula by their habit morphology (Dawson, 1944a). Fronds of 

C. caespitosa are repent, composed of compressed branches (oval 

in transection; Dawson, 1944a, pl. 46: fig. 4) that form compact, 
444 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

low-growing, dense mats, with fronds that abundantly produce 

rhizoidal attachment structures that make it rigid. In contrast, 

Gulf C. parvula is terete throughout, more erect, and composed 

of more open, looser, less rigid branches. Later, Dawson (1963a) 

considered Champia caespitosa to be a synonym of a broadly defined C. parvula; however, others still recognized it as distinct (e.g., 

Ramírez and Santelices, 1991). The taxonomic status of the two 

described northern Gulf of California species, C. caespitosa and 

C. disticha, needs to be reinvestigated. A comparative systematic 

study using molecular markers of type locality material of these 

Gulf species and type locality material of C. parvula would help 

determine if species separation is supported.

Champia disticha E. Y. Dawson

FIGURE 221A

Champia disticha E. Y. Dawson, 1944a:310, pl. 46: fig. 5; 1950d:341 [in 

part; not including Champia parvula]; 1963a:468 [in part; only C. disticha specimens]; González-González et al., 1996:190.

Small epiphytes 5–15 mm tall; of strongly compressed, 

hollow, regularly segmented axes and branches; in transection, 600–1100 μm wide and about 350 μm tall; distichously 

branched; short branches little constricted at base, with acute 

apices; branch segments much shorter than wide and slightly 

constricted at septa; attached below by a small rhizoidal holdfast, and sometimes secondarily by rhizoidal attachments from 

branches. Branches apparently developed at both septal nodes of 

segments and between the septa (internodes) (Dawson, 1944a: 

pl. 46: fig. 5). Cortex a single layer of small, slightly elongate, 

angular cells; inner side of cortical cells lined with longitudinal 

filaments that bear secretory cells toward the hollow cavity.

Reproductive structures unknown.

Habitat. Epiphytic on various algae, including Laurencia, Corallina, and Amphiroa; mid to low intertidal.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda to Isla San Esteban (Islas de la Cintura).

Type Locality. Isla San Esteban, Islas de la Cintura, Gulf of California, Mexico.

Remarks. Dawson (1944a) characterized Champia 

disticha, a little-known species, by its small size, strongly compressed branches, and distichous branching. In species of Champia

the origin of the branches is a character considered unique to the 

species (Ballantine and Lozada-Troche, 2008; Lozada-Troche and 

Ballantine, 2010). Since the illustration of Dawson (1944a: pl. 46: 

fig. 5) shows branches developed at the septal nodes of segments 

FIGURE 221. Species of Champia and Gastroclonium. A. Champia disticha: Holotype (after Dawson, 1944a: pl. 46: 

fig. 5). B. Champia caespitosa: Holotype (after Dawson, 1944a: pl. 46: fig. 3). C. Gastroclonium compressum: Habit 

(JN-5234, US Alg. Coll.-158972).
NUMBER 96 • 445

and from the internodes between the septa, the manner of branch 

formation in C. disticha needs to be re-examined. Champia disticha

somewhat resembles another flattened species, C. vieillardii Kützing (1866). Although similar in width to C. disticha (0.6–1.0 mm), 

C. vieillardii (0.7–1.5 mm) is not constricted at the septa, and it 

branches alternately to irregularly in more than one plane. Dawson 

(1963a) later considered C. disticha to be conspecific with a broadly 

defined C. parvula, but others have continued to recognize it (e.g., 

Silva et al., 1987). These two differ in that C. parvula is terete and 

usually radially alternately branched, and C. disticha is flattened and 

distichously branched. (See also Remarks for Champia caespitosa.)

Champia cf. parvula (C. Agardh) Harvey

FIGURE 222

Chondria parvula C. Agardh, 1824:207; Lozada-Troche and Ballantine, 

2010:140, fig. 18 [type specimen].

Champia parvula (C. Agardh) Harvey, 1853:76; Setchell and Gardner, 1930:153; Dawson, 1944a:310; Taylor, 1945:256; Dawson, 

1950d:337, 341 [in part]; 1957c:20; 1959a:28; Levring, 1960:58; 

Dawson, 1961b:437; 1963a:468 [in part; excluding C. caespitosa and

C. disticha], pl. 93; Huerta-Múzquiz and Tirado-Lizárraga, 1970:129; 

Chávez-Barrear, 1972b:269; Norris, 1973:15; Huerta-Múzquiz and 

Garza-Barrientos, 1975:9; Abbott and Hollenberg, 1976:565, fig. 

511; Y.-P. Lee, 1978:140, figs. 60–68, pl. IV: figs. D–F; Schnetter and 

Bula-Meyer, 1982:145, pl. 24: figs. B,C; Tseng, 1983:122, pl. 64: fig. 

2; Irvine and Guiry, 1983:78; Mendoza-González and Mateo-Cid, 

1986:425; Santelices and Abbott, 1987:9; Sánchez-Rodríguez et al., 

1989:44; Dreckmann et al., 1990:32, pl. 5: fig. 1; Ramírez and Santelices, 1991:294; Serviere-Zaragoza et al., 1993a:483; Stout and Dreckmann, 1993:15; Mateo-Cid et al., 1993:47; Mendoza-González et al., 

1994:107; González-González et al., 1996:306; Anaya-Reyna and 

Riosmena-Rodríguez, 1996:864, tbl. 1; Riosmena-Rodríguez et al., 

1998:28; Xia and Zhang, 1999:149, fig. 87; Mateo-Cid et al., 2000:66;

L. Aguilar-Rosas et al., 2000:131; Cruz-Ayala et al., 2001:191; 

CONANP, 2002:141; L. Aguilar-Rosas et al., 2002:234; Pacheco-Ruíz 

and Zertuche-González, 2002:468; López et al., 2004:11; RiosmenaRodríguez et al., 2005a:33; Mateo-Cid et al., 2006:56; ServiereZaragoza et al., 2007:9; Pacheco-Ruíz et al., 2008:210; LozadaTroche and Ballantine, 2010:139 [as “C. cf. parvula”], figs. 1–6, tbl. 3; 

Fernández-García et al., 2011:61.

Algae erect and spreading, forming soft clumps; up to 1.0(–

3.0) cm tall in the Gulf; cylindrical, of segmented hollow axes and 

branches. Hollow portions separated by transverse, monostromatic septa, constricted at the septal regions. Axes 1.0–2.5 mm 

in diameter; branches 0.5–1.5 mm in diameter, narrowing toward 

rounded apices. Branches originating at septal nodes of segments, 

axes irregularly alternately branched, radially arranged. Thalli attached basally to substratum and may be secondarily attached 

by prostrate axes and branches in contact with substratum, host 

alga, or sea grass. Cortical layer 1–2(–3) cells thick, a mixed pattern of large cells (up to about 30–40 μm in diameter by 60–80 

μm long) and frequent small spherical cells (to 10 μm in diameter) 

interspersed. Secretory cells simple, rounded, borne along multiple longitudinal filaments bordering the hollow cavities.

Tetrasporangia ovoid, 50–60 μm long, tetrahedrally divided, scattered in cortex, projecting inward.. Cystocarps sessile, 

protruding, conspicuous, 800–1000 μm in diameter, with an ostiole. Carposporangia clavate-obconical (up to 50 μm in diameter distally and up to 140 μm in length; e.g., Dawson, 1963a: pl. 

93, fig. D). Spermatangia not seen in Gulf material.

Habitat. On rocks or epiphytic on other algae; mid 

intertidal to shallow subtidal.

Distribution. Gulf of California: El Tornillal 

(Gulfo de Santa Clara) to San José del Cabo. Eastern Pacific: 

California Channel Islands to La Jolla (southern California); 

Baja California to Guerrero; Isla Socorro, Isla Clarión, and Isla 

San Benedicto (Islas Revillagigedo); El Salvador; Costa Rica; Isla 

Gorgona, Colombia; Ecuador; Rapa Nui (Easter Island; Isla de 

Pascua). Central Pacific: Hawaiian Islands (Abbott, 1999). Western Pacific: China (Tseng, 1983; Xia and Zhang, 1999); Japan 

(I. K. Lee, 1978; Yoshida, 1998); Korea (Y.-P. Lee, 2008).

Type Locality. “Ad Gades” (Agardh, 1824:207); 

Cádiz, Iberian Peninsula, southwestern Spain.

Remarks. The Gulf of California specimens that 

have been identified as “Champia parvula” need to be reinvestigated as the worldwide, broadly defined species concept of 

C. parvula appears to represent a complex of several species 

rather than a single entity. Molecular systematic studies will help 

elucidate if there is one or more species.

Gastroclonium Kützing

Gastroclonium Kützing, 1843:441, nom. cons.

Coeloseira Hollenberg, 1941[1940]:871.

Algae consisting of an erect, solid, terete stipe and erect or 

arching branches that arise from stoloniferous or discoid holdfasts. Branches are terete or compressed and either short and 

vesicle-like or long and divided into segments by transverse 

septa, with segments hollow and filled with a watery mucilage. 

Branching can be dichotomous, lateral, or irregular. Thalli multiaxial in structure, with grouped apical cells at apices. Branches 

composed of an outer incomplete layer of small cortical cells 

and an inner cortex of larger cells that are lined with parallel 

longitudinal filaments bearing inwardly directed secretory cells. 

Longitudinal filaments connect with the monostromatic septa 

separating the segments.

Reproductive structures are produced only on branches. 

Life history, where known, is triphasic (Polysiphonia-type; West 

and Hommersand, 1982). Polysporangia usually of 8–16 polyspores, or tetrahedrally divided tetrasporangia are scattered in 

distal branches (Guiry, 1990b). Gametangial thalli are dioecious. Female gametophytes are procarpic, with a 4-celled carpogonial branch that has two 2-celled auxiliary cell branches. 

The gonimoblast develops outward and produces large, wedgeshaped carposporangia directly from a large fusion cell. Cystocarps are scattered, protrude from the branch surface, and have 

a thick pericarp that lacks an ostiole and is without tela arachnoidea filaments. Spermatangia are developed in superficial sori 
446 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 222. Champia cf. parvula: A. Habit, showing branching pattern and segments at consistent intervals (JN-5311, US Alg. Coll.-158921). 

B. Branch originating from septal region and intermixed cortical pattern of larger cells cutting off small cells. C. Surface view of tetrasporangia 

scattered in cortex. D. Several segments with focus on the longitudinal filaments connecting with monostromatic septa cell layer (note orientation of this figure is perpendicular to the previous figures; B–D, JN-4001, US Alg. Coll. microscope slide 4583).
NUMBER 96 • 447

on the distal branches; spermatia terminal on elongated parent 

cells borne on branched filaments produced from the cortical 

cells.

Remarks. The solid, terete stipe and branched axes 

of Gastroclonium are the primary characters that differentiate 

it from the similar genera Chylocladia Greville in W. J. Hooker 

(1833) and Champia, both of which lack solid stipes or solid 

axes. Species of Gastroclonium occur in the North and South 

Atlantic, the Pacific Coast of North America, Gulf of California, 

Japan, China, and India.

Three species of Gastroclonium are known in the northern 

Gulf of California.

KEY TO THE SPECIES OF GASTROCLONIUM IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli 3–8 cm tall; branches more or less terete; cystocarps large, about 500 μm in diameter . . . . . . . . . . . G. pacificum

1b. Thalli smaller, usually less than 3 cm tall; branches terete to compressed; cystocarps smaller, less than 350 μm in 

diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Branches compressed; branch walls mostly 1 cell layer thick . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. compressum

2b. Branches terete; branch walls of 2–3 cell layers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. parvum

Gastroclonium compressum (Hollenberg) C. F. Chang et 

B.-M. Xia

FIGURE 221C

Coeloseira compressa Hollenberg, 1941:874, figs. 7c,d, 13–17; Smith, 

1944:304, pl. 76: fig. 2; Dawson et al., 1960a:24; Dawson, 1961b:438; 

1963a:469, pl. 95: figs. 3, 4, 7; Abbott and Hollenberg, 1976:566, fig. 

512; Devinny, 1978:359; Pacheco-Ruíz and Aguilar-Rosas, 1984:73; 

R. Aguilar-Rosas et al., 1990:125; R. Aguilar-Rosas and Aguilar-Rosas, 

1994:523; González-González et al., 1996:192; Riosmena-Rodríguez 

et al., 2005a:33.

Gastroclonium compressum (Hollenberg) C. F. Chang et B.-M. Xia, 

1978:209, 213; Ramírez and Santelices, 1991:295; Stewart, 1991:121; 

Hughey et al., 1996:432.

Algae erect, spreading, low growing, mostly 1–2(–3) cm tall 

in the Gulf; primary axes cylindrical, solid, short, up to 7 mm 

long; branches slightly compressed, up to 1 mm wide, appearing somewhat horizontal to axis, recurving toward substratum; 

attached by stoloniferous base; and where downward-curving 

branch apices contact substratum, a new thallus may develop 

at contact point. Hollow tubular branches divided by septa into 

regular segments, constricted at septa; branches simple or with 

a few short branchlets on side away from substratum. Outer 

cortex a continuous single cell layer, with an incomplete layer 

of slender, longitudinal filaments connecting to outer cells and 

bearing secretory cells.

Polysporangia globose, divided into 12–16 polyspores; scattered in upper portion of branches. Cystocarps scattered, protruding beyond surface of branches, 300–350 μm in diameter; 

without an ostiole. Spermatangia unknown in Gulf of California 

specimens.

Habitat. On rocks or tidal platform or sometimes 

epiphytic or entangled with other algae; mid intertidal to shallow 

subtidal, down to 2 m depths.

Distribution. Gulf of California: Playa Las Conchas (Playa Estación), Puerto Peñasco, to Isla Estanque (Islas de 

la Cintura). Eastern Pacific: Pacific Grove (central California) to 

Bahía de Ballenas (Baja California Sur); Islas Todos Santos (off 

Ensenada), Baja California; Chile.

Type Locality. Corona del Mar, Orange County, 

southern California, USA.

Remarks. Intertidal specimens of Gastroclonium 

compressum from Puerto Peñasco (JN-5129, JN-5234 ) and the 

south end of Isla Estanque (JN-5599) establish its presence in the 

northern Gulf of California. Northern Gulf G. compressum occurs in the intertidal to shallow subtidal, whereas in Pacific Mexico, it has been collected from 19 m depths in a large kelp bed off 

Islotes Chester, in the vicinity of Punta Eugenia (“San Eugenio”), 

Baja California Sur (Dawson, 1963a). Some Pacific Mexico Gastroclonium compressum are similar to G. cylindricum Santelices, 

I. A. Abbott et M. E. Ramírez (1989). Endemic to central Chile,

it differs primarily in having cylindrical branches throughout 

and branch walls of 2–4 cell layers.

Gastroclonium pacificum (E. Y. Dawson) C .F. Chang et 

B.-M. Xia

FIGURE 223

Coeloseira pacifica E. Y. Dawson, 1950a:343, fig. 2; 1961b:438; 1963a:469, 

pl. 94: figs. 1, 2; 1966a:25; González-González et al., 1996:192.

Gastroclonium pacificum (E. Y. Dawson) C. F. Chang et B.-M. Xia, 

1978:209; Yoshida, 1998:835, fig. 3-76E; Pacheco-Ruíz and 

Zertuche-González, 2002:468; Mateo-Cid et al., 2006:56; PachecoRuíz et al., 2008:210.

Gastroclonium clavatum sensu Dawson, 1944a:312 [non Gastroclonium 

clavatum (Roth) Ardissone, 1883:322].

Gastroclonium ovale sensu Okamura, 1907:74, pl. 17: figs. 1–10; 1936:688, 

fig. 2 [non Gastroclonium ovale (Hudson) Kützing, 1843:441, which 

is now Gastroclonium ovatum (Hudson) Papenfuss, 1944b:344; basionym: Fucus ovatus Hudson, 1762:468].

Algae erect, 3–8(–12) cm tall; 1 or more partially erect, 

arching, simple to multibranched, solid, cylindrical axes develop 

from stoloniferous basal branches and produce septate, tubular, 

hollow branches, 1–2 mm in diameter; branches often with secondary branches. Branch walls of 2–3 cell layers; outermost cortical cells slightly anticlinally elongate.

Polysporangia scattered in outer wall of branches. Cystocarps protruding, basally somewhat constricted; about 500 μm 
448 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

in diameter, without an ostiole; carpospores 100 μm long, 20–50 

μm in diameter. Spermatangia in a superficial layer over the 

upper portions of branches.

Habitat. On sand flats and on rocks and in crevices 

and tide pools; mid to low intertidal.

Distribution. Gulf of California: Bahía La Choya 

(Bahía Cholla) and Playa Tucson, Puerto Peñasco, to Bahía Bocochibampo, Sonora. Western Pacific: Japan.

Type Locality. Bahía Bocochibampo, near Guaymas, Sonora, Gulf of California, Mexico.

Remarks. Within the Gulf of California, Gastroclonium pacificum is possibly restricted in distribution to the northern Gulf. A single polysporic specimen that apparently lacked a 

solid axis from Punta Los Frailes (Baja California Sur) was also 

tentatively referred to G. pacificum (Dawson, 1963a, as “Coeloseria pacifica”); therefore, its southern Gulf distribution needs to 

be confirmed. It is also reported in Japan.

Gastroclonium parvum (Hollenberg) C. F. Chang et B.-M. Xia

Coeloseira parva Hollenberg, 1941:871, figs. 7a,b, 8–12; Dawson, 

1961b:438; 1963a:470, pl. 86: fig. 4, pl. 95: fig. 6; Abbott and Hollenberg, 1976:566, fig. 513; L. Aguilar-Rosas, 1981:94; Pacheco-Ruíz and 

Aguilar-Rosas, 1984:73; Stewart and Stewart, 1984:144; L. AguilarRosas et al., 1985:125; Mendoza-González and Mateo-Cid, 1986:425; 

Sánchez-Rodríguez et al., 1989:44; González-González et al., 1996:192.

Gastroclonium parvum (Hollenberg) C. F. Chang et B.-M. Xia, 1978:209; 

Stewart, 1991:121; Ramírez and Santelices, 1991:296; Mateo-Cid and 

Mendoza-González, 1994b:40; L. Aguilar-Rosas et al., 2000:131.

Algae of 1 or more erect individuals or in clumps, 2.0–3.0 cm 

tall, or forming dense mats (to 10 cm wide); erect, branched axes 

above unbranched or divided solid stipes (up to 1.0 mm in diameter) developed from a small discoid holdfast or from basal stoloniferous branches. Branching multifariously, branches terete, 

tubular; constricted septate branches, 1.0–1.5 mm in diameter, 

simple to repeatedly branched; branch walls of 2–3 cell layers; 

outermost cells 20–25 μm in diameter; inner cells 120–145 μm 

long, 60–70 μm in diameter, lined with few longitudinal filaments bearing secretory cells (gland cells).

Polysporangia 80–120 μm in diameter, divided into 12–16 

polyspores, scattered in walls of septate branches. Cystocarps 

prominent, subglobose, mostly 280–300 μm in diameter, without an ostiole; developed on septate branches. Spermatangia 

unknown.

Habitat. On rocks, sometimes among algal turf; mid 

to low intertidal, probably also shallow subtidal.

Distribution. Gulf of California: Puertecitos; 

Roca Rojo, Bahía Kino. Eastern Pacific: Pacific Grove (central 

California); Redondo Beach, southern California to Playa Los 

Cerritos (south of Todos Santos), Baja California Sur; Isla Guadalupe; Isla Cedros; Chile.

FIGURE 223. Gastroclonium pacificum: Habit (EYD-1808, US Alg. Coll.-207564).
NUMBER 96 • 449

Type Locality. Intertidal rocks; Redondo Beach, 

Los Angeles County, southern California, USA.

Faucheaceae

Faucheaceae I. M. Strachan, G. W. Saunders et Kraft in Saunders et al., 

1999:36 [non Gloiocladiaceae Harvey, 1836:160, as “Gloiocladeae,” 

which is based on Gloiosiphonia Carmichael in Berkeley, 1833:45, and 

not on Gloiocladia].

Algae are constructed with an assortment of different anatomical structures. Internally, some have a solid, pseudoparenchymatous medulla, whereas in other members the medulla 

is hollow. The cortex may be either thin and of small cells or 

thicker, with numerous cells in anticlinal rows.

Tetrasporangia are cruciately to irregularly divided and 

borne terminally or laterally. Gametophytes are monoecious 

or dioecious. Female gametophytes are procarpic; carpogonial 

branches are three-celled. Gonimoblasts are globular, composed 

of several gonimolobes, with most of their cells developing into 

carposporangia. The fusion cell is narrow. Well-developed tela 

arachnoidea (network of slender stellate cells that look like spiderwebs) filaments surround the carposporophyte.

Two genera of the Faucheaceae are represented in the northern Gulf of California.

KEY TO THE GENERA OF FAUCHEACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli not mucilaginous; dichotomous branches remaining free (not anastomosing) . . . . . . . . . . . . . . . . . . Gloiocladia

1b. Thalli mucilaginous; abundantly dichotomously to subdichotomously branched; branches anastomosing . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gloioderma

Gloiocladia J. Agardh

Gloiocladia J. Agardh, 1842:87; J. Agardh, 1851:246; Rodríguez-Prieto et 

al., 2007:156.

Fauchea Montagne et Bory de Saint-Vincent in Montagne, 1846b:64; Kylin, 

1956:330.

Algae are erect or prostrate, terete, compressed, or flattened, 

variously branched fronds that are attached to the substratum by 

a discoid holdfast and secondarily by marginal haptera. Branching is usually radially or complanately branched, but some are 

subdichotomously or pinnately branched. The Gulf of California 

species are mostly repeatedly, dichotomously branched (not always clear). Thalli are multiaxial in construction and solid. The 

medulla is composed of large, colorless cells (elongated in longitudinal section), and smaller secondary medullary cells may be 

present. Rhizoidal filaments that are issued from inner cortical 

or outer medullary cells may be present in the medulla, usually 

in the basal portions of the thallus. The inner subcortex is of 

smaller, ovoid to angular cells that are interconnected by numerous secondary pit connections. The outer cortical filaments 

arise from the subcortex, composed of simple or pseudodichotomously branched anticlinal rows of small cells that are without 

lateral secondary pit connections.

Tetrasporangia are ovoid, oblong, or fusiform, cruciately, 

decussately cruciate, or irregularly divided, and scattered or 

either within slightly elevated nemathecial sori or in distinctly 

raised nemathecia. Gametophytes are monoecious or dioecious. 

Female gametophytes are procarpic, with a three-celled carpogonial branch that either lacks or has a lateral sterile cell on the 

first cell of the carpogonial branch, borne on a supporting cell, 

which also bears a two-celled auxiliary cell branch (auxiliary 

parent cell and an auxiliary cell). After fertilization, the carpogonial branch cells fuse and connect to the auxiliary cell, which 

divides transversely to form a primary gonimoblast cell. A fusion 

cell is formed by the coalescence of the auxiliary and auxiliary 

parent cell and the fused cells of the carpogonial branch and 

the surrounding cells; the supporting cell may also sometimes 

participate in the fusion process. Only the supporting cell of the 

fusion cell remains discernible; other cells forming the fusion cell 

become unrecognizable as the structure matures. The gonimoblast is produced from the distal end of the primary gonimoblast 

cell, above a spherical mass of nutritive cells, and generates elongated lobes of ovoid carposporangia that are surrounded by tela 

arachnoidea (a network of persistent spiderweb-like filaments) in 

the cystocarp. Cystocarps are protruding, globose, and ostiolate, 

with surfaces that may be smooth (without ornamentation) or, 

in some species, coronate and either sessile or borne substipitate 

along the margins or scattered over the thallus surface. Spermatangia cut off singly or in pairs from spermatangial parent 

cells that arise from outer cortical cells, forming superficial sori 

(after Rodríguez-Prieto et al., 2007).

Remarks. Species of Gloiocladia occur mostly in 

warm-temperate to tropical seas, although a few are known in 

cold-temperate waters. Ballantine and Norris (1989) noted that 

the species cannot be distinguished by only using the characters 

of thallus shape and branching.

The closely related genera Gloiocladia and Fauchea had 

been separated on morphological characters (e.g., Irvine and 

Guiry, 1980; Norris, 1991). The respective type species for 

these two genera—Gloiocladia furcata (C. Agardh) J. Agardh, 

1842 [basionym: Chondria furcata C. Agardh, 1827)] and Fauchea repens (C. Agardh) Montagne et Bory de Saint-Vincent in 

Montagne, 1846b [basionym: Sphaerococcus repens C. Agardh, 

1823, which is now Gloiocladia repens (C. Agardh) Sánchez et 

Rodríguez-Prieto]—were shown to be congeneric by RodríguezPrieto et al. (2007). Because Gloiocladia is the oldest validly 

published name, other species referred to “Fauchea” will require 

generic reassessment and molecular confirmation.

Three species of Gloiocladia are known in the Gulf of California; all of them are currently considered to be endemic species.
450 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

KEY TO THE SPECIES OF GLOIOCLADIA IN THE GULF OF CALIFORNIA

1a. Thalli forming dense clumps of short, congested, often overlapping branches; branches 3–5 mm wide . . . . . . G. mollis

1b. Thalli openly branched (not in dense clumps); branches narrower, mostly 2–3 mm wide . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Branches mostly 2.0–2.5 mm wide; branching generally 3–5 times at intervals of 1–2 cm; cystocarps distinctly coronate, 

with horn-like projections up to 1 mm long . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. hoshawii

2b. Branches mostly 2.0–4.0 mm wide; branching generally 4–11 times at intervals of (1)2–4 cm; cystocarps with smooth 

surface (not ornamented) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . G. sefferi

Gloiocladia hoshawii (E. Y. Dawson) J. N. Norris, comb. nov.

FIGURE 224

Fauchea hoshawii E. Y. Dawson, 1966b:64, fig. 5 [type specimen]; GonzálezGonzález et al., 1996:201; Pacheco-Ruíz and Zertuche-González, 

2002:468; Pacheco-Ruíz et al., 2008:210.

Algae erect, up to 5 cm tall; fronds lubricous, of narrow, 

strap-like dichotomous branches, 2.0–2.5 mm wide; 3–4(–7) 

times divided, mostly at intervals of (0.5–)1–2 cm; upper branches 

narrower, ultimate branches 1 mm wide below bifurcate apices; 

branch angles wider in lower portions, narrowing in upper portions; attachment structures not known. Transection about 300 

μm thick, medulla pseudoparenchymatous and compact, of large 

hyaline ovoid cells; cortex of anticlinal rows of small cells.

Tetrasporangia ovoid, cruciately divided, small, 24–35 μm 

long, (10–)12–15 μm in diameter; among modified cortical filaments (slightly longer as cortical cells become more elongate), creating a slightly elevated nemathecial sori borne on one side of a 

branch (Figure 224C). Cystocarps borne along margins; about 750 

μm in diameter; distinctly coronate, with 3–5 straight or curved 

horn-like projections up to 1 mm or more in length; tela arachnoidea surround carposporophyte. Spermatangia not known.

Habitat. On rocks; subtidal, down to at least 21 m 

depths.

Distribution. Gulf of California: Islas de Los Gemelos (Islas Los Hermanitos), off Bahía de Los Ángeles; Isla San 

Pedro Nolasco.

Type Locality. Isla San Pedro Nolasco, off Guaymas, Sonora, Gulf of California, Mexico.

Remarks. A northern Gulf of California endemic, 

Gloiocladia hoshawii is easily recognized from the other Gulf 

species of Gloiocladia by its distinctly ornamented, coronate 

cystocarps. Tetrasporophytes are reported for the first time 

from subtidal collections from Islas de Los Gemelos (JN-3008, 

US Alg. Coll.-159134 ). This species was named for Robert W. 

Hoshaw (University of Arizona), phycologist, teacher, and mentor, who supported and encouraged studies of the Gulf of California marine algae.

Gloiocladia mollis (M. Howe) J. N. Norris, comb. nov.

FIGURE 225

Fauchea mollis M. Howe, 1911:507, pl. 32, pl. 33: fig. 6; Dawson, 

1944a:304; 1961b:435; 1963a:440, pl. 78: fig. 2; González-González 

et al., 1996:201.

Algae low growing, forming a dense clump, 6–9 cm wide; of 

dichotomous branches developed centrally and growing radially 

outward, more or less overlapping; outer portions of branches 

becoming erect, short and polychotomous, with segments 3–5 

mm wide; outermost segments very short, rounded lobes, 1.5–

2.0 mm wide. Branches 165–350 μm thick; medulla pseudoparenchymatous of 2–3 layers of large cells, 75–275 μm in diameter.

Tetrasporangial thalli (apparently immature) with cortex of 

4–5 cell layers; small cortical cells 5–9 μm in diameter. Gametangial thalli of type (apparently immature; queried by Dawson, 

1963a) with cortex of 2 layers of small cells, 5–9 μm tall and 5–9 

μm in diameter (after Dawson, 1963a).

Habitat. On rocks; subtidal, dredged at 10–40 m 

depths.

Distribution. Gulf of California: Isla San Esteban; 

La Paz.

Type Locality. “Apparently dredged, vicinity of La 

Paz,” Baja California Sur, Gulf of California, Mexico (Dawson, 

1963a:441).

Remarks. Dawson (1963a, as “Fauchea mollis”) 

noted the structure of the Isla San Esteban Gloiocladia mollis was 

very close to his understanding of the genus Fauchea (cf. Kylin, 

1931). The finding of mature gametangial thalli, as well as tetrasporangial thalli, is needed to confirm the generic placement of 

this Gulf species and its relationship to Pacific coast Gloiocladia 

laciniata (J. Agardh) Sánchez et Rodriguez-Prieto (RodriguezPrieto et al., 2007; basionym: Fauchea laciniata J. Agardh, 1885).

Gloiocladia sefferi (M. Howe) J. N. Norris, comb. nov.

FIGURE 226

Fauchea sefferi M. Howe, 1911:506, fig. 31; Dawson, 1944a:304; 

1961b:455; 1963a:441, pl. 78: fig. 1; 1966b:64; González-González 

et al., 1996:201; CONANP, 2002:141; Pacheco-Ruíz and ZertucheGonzález, 2002:468; Pacheco-Ruíz et al., 2008:210.

Algae erect, up to 12 cm tall; of narrow, strap-like dichotomous to subdichotomous branches of similar width throughout, (1–)2–4 mm wide, more or less divaricately branched 4–11 

times, mostly at (1–)2–4 cm intervals, with smooth margins; 

ultimate segments abruptly tapering to blunt to semiacute apices; attached by small, irregularly discoid holdfast. Transection 

150–400 μm thick; medulla of 4–6 irregular rows of pseudoparenchymatous cells, 70–100 μm in diameter; abrupt transition to 

subcortex of 1–2 layers of small, pigmented cells, wider than 

tall, about 10 μm wide; outer cortex of anticlinal rows of 4–8, 

pigmented cortical cells, 3–8 μm in diameter.

Tetrasporangial thalli unknown. Cystocarps relatively 

sparse on margins; sessile, subspherical, 600–700 μm in diameter, noncoronate (lack ornamentation); tela arachnoidea surround the carposporophyte. Spermatangial thalli unknown.
NUMBER 96 • 451

Habitat. On rocks; subtidal, 8–14 m (also dredged 

to 40 m depths).

Distribution. Gulf of California: Isla Estanque 

(off southeast end of Isla Ángel de la Guarda), Isla San Esteban 

and Isla San Lorenzo (Islas de la Cintura); Isla Coronado (Isla 

Smith), off Bahía de Los Ángeles; Puerto Escondido to La Paz.

Type Locality. “Apparently dredged, vicinity of La 

Paz,” Baja California Sur, Gulf of California, Mexico (Dawson, 

1963a:441).

Remarks. Specimens from the subtidal off the north 

end of Isla Coronado (JN-4336, US Alg. Coll.-159135) have the 

prominent, smooth (nonornamented) cystocarps, with a small 

FIGURE 224. Gloiocladia hoshawii: A. Thallus with marginal cystocarps that are adorned with straight or curved coronate “horns.” Inset: 

Detail of coronate horns on cystocarps (holotype: R. Hoshaw & E. Y. Dawson, s.n., US Alg. Coll.-40926). B. Habit of tetrasporangial thallus 

(JN-3008, US Alg. Coll.-159134). C. Transection of branch with tetrasporangial sori in modified cortex. D. Transection of branch (C, D, JN3008, US Alg. Coll. microscope slides 4595 and 4596).
452 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

ostiole, characteristic of Gloiocladia sefferi (US Alg. Coll. microscope slide 4233).

Gloioderma J. Agardh

Gloioderma J. Agardh, 1851:243.

Estebania Setchell et N. L. Gardner, 1924:783.

Thalli in the Gulf of California are of compressed, highly 

lubricous, strap-like fronds with branching that either remains 

dichotomous or becomes subdichotomous; the uppermost portions are dichotomously branched. Branches fuse where they 

are in contact with each other frequently anastomosing with 

small to large openings. Medulla is initially of 1–2(–3) layers 

of large, thick-walled ovoid cells; subsequently, thin, medullary 

filaments begin growing and branch, becoming intertwined and 

densely filling the central medulla. Cells of the outer medulla 

grade into an inner cortex of one to two layers of smaller ovoid 

cells. The outer cortex is formed by anticlinal rows of little 

cells.

Tetrasporangia are cruciately divided and scattered over the 

thallus surface (not in sori). Cystocarps and spermatangia remain unknown (genus description modified from Setchell and 

Gardner, 1924).

Remarks. Norris (1991) and others (e.g., Womersley, 

1996; Sánchez and Rodríguez-Prieto, 2005) considered Gloioderma (generitype: Gloioderma australe J. Agardh, 1851:243; 

type locality: Western Australia) to be congeneric with Gloiocladia (generitype: Gloiocladia furcata (C. Agardh) J. Agardh, 

1842; type locality: Trieste, Italy). Nevertheless, on the basis of 

morphological and molecular analyses, Rodríguez-Prieto et al. 

FIGURE 225. Gloiocladia mollis: Habit (EYD-21579, US Alg. 

Coll.-51351).

FIGURE 226. Gloiocladia sefferi: A. Habit, narrow branched axes; 

note cystocarps protruding along margins (JN-4336, US Alg. Coll.-

159135). B. Habit, wide axes with unornamented cystocarps borne 

along margins (EYD-21558, US Alg. Coll.-7202). C. A cystocarp in 

transection showing nutritive cells below the fusion cell and “tela 

arachnoidea” (spiderweb-like filaments) that surround the carposporophyte (note slide preparation has squashed the carposporangia 

out) (JN-4336, US Alg. Coll. microscope slide 4233).
NUMBER 96 • 453

(2007) and Dalen and Saunders (2007) concluded that Gloioderma should be reinstated.

For now, the Gulf of California species is considered to belong to Gloioderma, until the generic status of Gulf G. conjuncta

can be further investigated with the finding of carposporangial 

and spermatangial thalli and with new anatomical and molecular data. If the Gulf G. conjuncta proves to be a distinct genus, 

then the name Estebania Setchell et N. L. Gardner (1924) would 

be available for consideration.

There is one species of Gloioderma represented in the northern Gulf of California.

Gloioderma conjuncta (Setchell et N. L. Gardner) E. Y. 

Dawson

FIGURE 227

Estebania conjuncta Setchell et N. L. Gardner, 1924:783, pl. 25: figs. 35, 36, 

pls. 85, 86; Dawson, 1944a:281.

Gloioderma conjuncta (Setchell et N. L. Gardner) E. Y. Dawson, 1959a:26; 

1961b:435; 1963a:442, pl. 79; 1966a:27; Norris, 1973:14; GonzálezGonzález et al., 1996:212; CONANP, 2002:141; Pacheco-Ruíz and 

Zertuche-González, 2002:468; Mateo-Cid et al., 2006:52; PachecoRuíz et al., 2008:210.

Gloiocladia conjuncta (Setchell et N. L. Gardner) R. E. Norris, 1991:592.

Algae erect, of flattened, branched, strap-like fronds, mostly 

4–5(–8) mm wide, up to 70 cm in length; divaricately dichotomously branched (easily seen in upper [distal] growing portions); 

extensively branched and developing into distinctive anastomosing fronds with open spaces between branches formed by 

coalescing of developing branches; initially, openings less than 

0.5 mm in diameter, becoming much larger, up to 2(–5) cm in diameter as branches grow, anatomoses often becoming torn open; 

thallus firm with a slippery mucilaginous texture, iridescent light 

greenish rose or yellowish to coral-red (drying reddish orange 

to brick brown); usually entangled, attachment not fully understood or apparently attached where branches contact host alga. 

Medulla initially (young developing thalli) of 1–2 layers of large, 

thick-walled, ovoid cells, up to 200 μm in diameter; later, central 

medulla develops intertwined, branched medullary filaments, 

3–4 μm in diameter; thin filaments becoming dense; medullary 

filaments surrounded by 2(–3) layers of large, ovoid medullary 

cells that grade into outer medulla; inner cortex of (1–)2–3 layers 

of small, thin-walled cells; outer cortex of anticlinal rows of 4–7 

subspherical cells, each 4–6 μm in diameter.

Asexual reproduction by fragmentation; drifting portions 

becoming entangled with other algae. Tetrasporangia cruciately 

divided; developed in inner cortical layers; scattered over both 

thallus surfaces. Gametangial thalli unknown.

Habitat. Usually epiphytic or entangled with other 

algae; sometimes free floating or also apparently occasionally on 

rocks; shallow subtidal, down to 40 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to Isla San Pedro Mártir; Puerto Refugio, Isla Ángel de la Guarda 

and Isla San Esteban (Islas de la Cintura) to Bahía Agua Verde; 

Isla de Tortuga, about 24.1 km (15 miles) northeast of Isla San 

Marcos (Baja California Sur).

Type Locality. Isla San Esteban, Islas de la Cintura, Gulf of California, Mexico.

Remarks. The Gulf endemic Gloioderma conjuncta,

with its slippery texture, extensively branched, distinctive anastomosing fronds with open spaces (holes) formed by the coalescing of 

developing branches, is unique among the Gulf of California algae.

Lomentariaceae

Lomentariaceae J. Agardh, 1876:606, 630, nom. cons.; Saunders et al., 

1999:35.

Chondrosiphonaceae Kützing, 1843:438, nom. rej.

Algae are soft and flaccid, semicartilaginous to rigid, and oppositely, alternately, or irregularly branched; axes and branches 

are terete to compressed; thalli are entirely solid or partially to 

mostly hollow, with polystromatic partitions (septa) dividing the 

hollow space. Thalli are multiaxial in structure, with a cortex of 

one to several cell layers; the medulla is either compact to loosely 

aggregated and solid throughout, of larger, elongated cells, or 

is hollow with pseudoparenchymatous septa, and a network of 

loosely arranged, narrow, longitudinal filaments peripherally lining the hollow central cavities.

Life histories, where known, involve isomorphic sporophytes and gametophytes. Tetrasporangia are tetrahedrally 

(or infrequently cruciately) divided, borne terminal on cortical 

cells, developed within sori associated with sterile filaments, 

in depressions or cavities in branches or branchlets or in swollen branch apices. Gametophytes are dioecious. Carpogonial 

branches are three-celled, borne on a supporting cell that also 

bears one to two two-celled auxiliary cell branches (procarpic). 

The gonimoblast develops from the basal fusion cell. Nearly all 

of the gonimoblast cells become carposporangia. Cystocarps, 

with a cortical pericarp and ostiole, protrude above the thallus 

surface and are scattered over the branches. Spermatangia are 

developed from initials that are cut off from outer cortical cells 

in inconspicuous sori on thallus surface or in swollen branch 

apices.

Two genera of the Lomentariaceae occur in the northern 

Gulf of California.

KEY TO GENERA OF THE LOMENTARIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Axes and branches wiry, stiff, terete, less than 1 mm in diameter; internally solid, with a medulla of loose to compact, 

longitudinal filaments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ceratodictyon

1b. Axes and branches flaccid to semicartilaginous, terete to compressed, most greater than 1 mm in diameter; internally with 

hollow portions separated by polystromatic partitions (multiple cell layers) . . . . . . . . . . . . . . . . . . . . . . . . . Lomentaria
454 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 227. Habits of Gloioderma conjuncta: A. Habit with more open 

branching pattern (D. Bean, s.n., US Alg. Coll.-94253). B. Branching of 

anastomosing frond with open spaces (holes) formed by the coalescing of 

two branches (JN-5276, US Alg. Coll.-159529).
NUMBER 96 • 455

Ceratodictyon Zanardini

Ceratodictyon Zanardini, 1878:36.

Gelidiopsis F. Schmitz, 1895:148.

Algae are erect, composed of thin, terete, or subcylindrical 

(sometimes to compressed) cartilaginous axes that are subdichotomously to irregularly branched, with rounded apices, and arise 

from prostrate stoloniferous branch systems. Axes and branches 

are often entangled, sometimes anastomosing (in a few species), 

and often form clumps or are mat-like. Thalli are multiaxial in 

construction, with a medulla composed of slender, elongated filaments that become larger and increasingly elongate toward the 

center (seen in longitudinal section). The cortex has one to several layers of smaller cuboidal or rectilinear cortical cells.

Reproductive structures are on swollen terminal branches. 

Tetrasporangia are regularly or irregularly cruciately divided, 

within terminal nemathecia that completely encircle the terete 

unbranched fertile axes. Tetrasporangia initials are formed terminally in a lateral position. Gametangial thalli are dioecious. 

Procarpic; carpogonial branches are three-celled, borne on a 

slightly enlarged supporting cell with a two-celled auxiliary cell 

branch. After presumed fertilization, the initial division of the 

zygote is oblique or nearly longitudinal. The gonimoblast develops outward from a fusion cell that remains as a large columnar structure within the cystocarp. Carposporangia are borne 

in short terminal chains on gonimoblast filaments, most develop 

synchronously in a single gonimolobe, and tela arachnoidea are

absent. Cystocarps have an ostiole and are mostly in groups on 

the branches, each conspicuously protruding outward. Spermatangia develop from spermatangial initials that are produced 

from cortical cells.

Remarks. Some of the species are free-living, 

others grow symbiotically within sponges. In describing the 

genus, Gelidiopsis, Schmitz (1895a) recognized its similarities 

to Ceratodictyon Zanardini (1878). Although much later Norris (1987b) would consider Gelidiopsis to be congeneric with 

Ceratodictyon, Price and Kraft (1991) suggested that the two 

should be retained as separate genera. More recent molecular 

systematic studies of Le Gall et al. (2008) included some species of Ceratodictyon and provided support to Norris’ (1987b) 

merging of the two genera.

Ceratodictyon (as Gelidiopsis) has an interesting history of 

familial placement. Primarily on the basis of its usual lack of 

reproduction and habit resemblance to Gelidium, some placed it 

as Gelidiopsis in the Gelidiaceae (e.g., Dawson, 1953a; Taylor, 

1960). Kylin (1956) placed the genus in the Gigartinales. Subsequently, Dawson (1961a) and, later, Norris (1987b), after studying the generitype, Gelidiopsis variabilis, considered the genus in 

the Gracilariaceae, whereas Price and Scott (1992) placed it in 

the Rhodymeniaceae. The molecular systematic studies of Saunders et al. (1999) showed the now congeneric Ceratodictyon and 

Gelidiopsis should be placed in the Lomentariaceae.

Two species of Ceratodictyon are known in the northern 

Gulf of California.

KEY TO THE SPECIES OF CERATODICTYON IN THE NORTHERN GULF OF CALIFORNIA

1a. Thalli short, up to 6 cm tall; with narrow branches, 250–400 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . C. tenuis

1b. Thalli taller, up to 20 cm tall; branches wider, 500–850 μm in diameter . . . . . . . . . . . . . . . . . . . . . . . . . . . C. variabile

Ceratodictyon tenuis (Setchell et N. L. Gardner) J. N. Norris, 

comb. nov.

Gelidiopsis tenuis Setchell et N. L. Gardner, 1924:749, pl. 22: fig. 2; Dawson, 

1944a:264, pl. 70: fig. 1; 1949c:246; 1953a:85; 1957c:16; 1959a:20; 

1961a:201, pl. 9: fig.1; 1961b:429; Huerta-Múzquiz and TiradoLizárraga, 1970:128; Chávez-Barrear, 1972b:268; Huerta-Múzquiz 

and Garza-Barrientos, 1975:9; Huerta-Múzquiz and MendozaGonzález, 1985:50; Mateo-Cid and Mendoza-González, 1992:20; 

Mendoza-González and Mateo-Cid, 1992:19; Serviere-Zaragoza et al., 

1993a:483; León-Tejera et al., 1993:200; Mateo-Cid et al., 1993:48; 

Mendoza-González et al., 1994:107; González-González et al., 

1996:204; Cruz-Ayala et al., 2001:191; CONANP, 2002:139; López 

et al., 2004:11; Serviere-Zaragoza et al., 2007:10; Benecker, 2009:CDRom p. 64.

Gelidiopsis variabilis sensu Fernández-García et al., 2011:62 [non Gelidiopsis variabilis (Greville ex J. Agardh) Schmitz, 1895:148].

Algae up to 6 cm tall, of erect, terete to compressed axes and 

branches, 250–400 μm in diameter; subdichotomously to irregularly branched, usually at 2–10 mm intervals; apices rounded; 

thallus base of loosely entangled, horizontal stoloniferous axes, 

up to 500 μm in diameter, attached at various points by small 

discs. Medulla a central core of narrow elongated cells, 8–9 μm 

in diameter, 90–135 μm long; outward surrounded by wider and 

shorter medullary cells, up to 30 μm in diameter; merging into 

a cortex of 2–3 layers; outermost cortical layer of small cells, 

mostly about 8 μm in diameter.

Reproduction not known in the Gulf of California.

Habitat. On rocks or loosely aggregated rock and 

sand or on crustose corallines; intertidal, also dredged down to 

40 m depths (Dawson, 1953a).

Distribution. Gulf of California: Guaymas to San 

José del Cabo; Mazatlán, Sinaloa to Nayarit. Eastern Pacific: Isla 

Socorro and Isla Clarión (Islas Revillagigedo); Jalisco to Oaxaca; 

El Salvador; Costa Rica; Nicaragua; Panama.

Type Locality. Santa Rosalía, Baja California Sur, 

Gulf of California, Mexico.

Remarks. Ceratodictyon tenuis is similar in habit to 

C. variabile but smaller in overall size, including the diameter 

of its branches (Dawson, 1953a). Comparisons of reproductive 

structures, once they are found in Gulf specimens, are needed, as 
456 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

well as molecular analyses of Gulf C. tenuis and Gulf C.variabile, 

to help elucidate their taxonomic status and relationship to type 

locality C. variabile.

Ceratodictyon variabile (Greville ex J. Agardh) R. E. Norris

FIGURE 228

Gelidium variabile Greville ex J. Agardh, 1851:468; Kützing, 1869:9, pl. 23: 

figs. c,d.

Ceratodictyon variabile (Greville ex J. Agardh) R. E. Norris, 1987a:243, figs. 

1–9; Le Gall et al., 2008:1567.

Gelidiopsis variabilis (Greville ex J. Agardh) Schmitz, 1895:148; Feldmann, 

1931:156, fig. 2B; Dawson, 1944a:225, pl. 70: fig. 1; 1953a:86; 

1960b:38; 1961a:201, pl. 9: fig.2; 1961b:429; 1966a:21; Santelices 

and Abbott, 1987:9; Norris, 1985d:212; Sánchez-Rodríguez et al., 

1989:44; Ramírez and Santelices, 1991:273; Mateo-Cid and MendozaGonzález, 1992:20; Mendoza-González and Mateo-Cid, 1992:19; 

Serviere-Zaragoza et al., 1993a:483; Mendoza-González et al., 

1994:107; González-González et al., 1996:204; Abbott, 1999:222, fig. 

61C,D; Mateo-Cid et al., 2000:65; L. Aguilar-Rosas et al., 2000:131; 

Mateo-Cid et al., 2006:56; Y.-P. Lee, 2008:415, figs. A–C.

Acrocarpus gracilis Kützing, 1849:761.

Gelidiopsis gracilis (Kützing) Feldmann, 1931:157; Yoshida, 1998:853.

Algae erect, up to 20 cm tall; of wiry, stiff, terete to sometimes slightly compressed axes, 500–850 μm in diameter; subdichotomously, irregularly alternately, or more or less oppositely 

branched; axes arising from loosely entangled, stoloniferous 

basal axes that attach by small discs. Medulla solid, of closely 

packed cells; central cells 10–15 μm in diameter, 150–280 μm 

FIGURE 228. Ceratodictyon variabile: Habit, from a clump of rigid, wiry thalli (JN-6087, US Alg. Coll.-159333). 
NUMBER 96 • 457

long (in longitudinal section); becoming slightly wider outward, 

with medullary cells 15–20 μm in diameter and shorter, 45–80 

μm long. Cortex of 2–3 layers of squarish cells, up to 8.0 μm in 

diameter; outermost cells, slightly flattened.

Tetrasporangial and gametangial thalli unknown in the Gulf 

of California. Tetrasporangia as reported elsewhere: with cruciately arranged spores, among slender filaments; in wide, swollen 

arrowhead-shaped sori borne terminal on tetrasporangial branchlets (after Abbott, 1999). Carpogonial branches (Norris, 1987a) and 

cystocarps have been reported elsewhere (see Price and Kraft, 1991).

Habitat. On rocks and tidal platforms; mid intertidal to shallow subtidal, down to 1.5 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to Cabeza Ballena; Mazatlán, Sinaloa to Nayarit. Eastern Pacific: 

Bahía Magdalena, Baja California Sur; Jalisco to Colima; Rapa 

Nui (Easter Island; Isla de Pascua). Central Pacific: Hawaiian 

Islands. Western Pacific: Japan; Korea; Vietnam.

Type Locality. Madras (now Chennai), Tamil 

Nadu, southeastern India.

Remarks. Northern Gulf specimens appear to be in 

agreement with Ceratodictyon variabile but should be tested and 

compared to type locality materials of G. variabile, the smaller 

Gulf of California C. tenuis, and to the generitype C. spongiosum

(Zanardini, 1878) from Indonesia (Silva et al., 1996a). Specimens of “G. variabilis” from Isla San Pedro Nolasco were noted 

by Dawson (1959a:20) to have “compressed branches and axes 

and occasional opposite branches” and should be reexamined.

Lomentaria Lyngbye

Lomentaria Lyngbye, 1819:101.

Algae are usually erect, but some may be repent or partly 

prostrate, composed of terete to compressed axes that are 

variously branched; branches are hollow with solid septa, and 

branch tips are rounded. Multiaxial in construction, thalli have 

a cortex of one to three cell layers and medulla of three to six cell 

layers, with hollow cavities lined with a network of longitudinal 

elongated medullary cells. Medullary cells become compacted 

into transverse polystromatic partitions (septa) at various intervals. Some species have multilayered septa that separate the hollow space into segments (sometimes constricted); other species 

have septa that only occur at branch bases. Secretory cells are 

borne on the medullary filaments, on the inward side facing the 

mucilage filled cavity.

Life histories, where known, include isomorphic tetrasporophytes and gametophytes. Tetrasporangia are tetrahedrally 

divided, borne within sunken sori formed by depressions as the 

cortex infolds, and cut off thallus inward from small cells lining 

the depressions. Gametophytes are typically dioecious but are 

monoecious in a few species. Carpogonial branches are threecelled, with one or two (one of which is nonfunctional) auxiliary 

cell branches composed of two cells. Gonimoblast filaments develop outward from a columnar fusion cell, with most of their 

cells forming carposporangia. Cystocarps are scattered and protrude above the thallus surface, with a three- to six-cell-thick 

pericarp (derived from the outer cortex), with a prominent pore 

and weakly developed tela arachnoidea internally. Spermatangia 

are in superficial sori, borne terminally on parent cells that are 

derived from outer cortical cells.

Remarks. Although the genus Lomentaria is widely 

reported, it is more common in distribution in subtropical to 

temperate seas and less so in the tropics and polar regions. Guiry 

(in Irvine and Guiry, 1983) has suggested the compressed to 

flattened species of Lomentaria with nonconstricted segments 

should be placed into a separate genus, Chondrothamnion Kützing (1843), thus restricting Lomentaria to the species with constricted segments. Many of the species are poorly understood, 

and the phylogenetic relationship between species of Lomentaria, Coelothrix Børgesen (1920), Binghamia J. Agardh (1894), 

and Binghamiopsis I. K. Lee, J. A. West et Hommersand (1988) 

needs comparative morphological and molecular testing and elucidation (Guiry and Guiry, 2009). 

Two species of Lomentaria are recorded in the northern 

Gulf of California.

KEY TO THE SPECIES OF LOMENTARIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Semicartilaginous; terete branches 1.0–2.0 mm in diameter, sometimes slightly constricted at more or less regular intervals into fusiform segments; variously branched; thallus wall 120–160 μm thick in transection from surface to hollow 

cavity; tetrasporangia surrounded by filamentous network within sunken sori . . . . . . . . . . . . . . . . . . . . . . . L. catenata

1b. Flaccid, gelatinous; terete to compressed branches, mostly 0.8–1.0 mm (occasionally to 1.3 mm) wide, slightly constricted 

only at branch bases; branching mostly opposite; thallus wall thinner in transection, 75–120 μm thick from cortex to 

hollow cavity; network of filamentous cells not well developed in sunken tetrasporangial sori . . . . . . . L. hakodatensis

Lomentaria catenata Harvey

FIGURES 229

Lomentaria catenata Harvey, 1857:331; Harvey, 1860:331; Okamura, 

1902:75, 103, pl. 26; Dawson, 1944a:308, pl. 74: fig. 1; 1953c:3; 

1954e:340; 1959b:16; 1960c:97; 1961b:437; 1963a:465, pl. 92: 

figs. 1–10; Norris, 1973:15; Huerta-Múzquiz, 1978:337; I. K. Lee, 

1978:124, figs. 53–59, pl. 5: figs. D–F; Norris, 1985d:213; Masuda et 

al., 1995:196, fig. 20; González-González et al., 1996:242; Yoshida, 

1998:837, fig. 3-76H–J; Xia and Zhang, 1999:153, fig. 89; L. AguilarRosas et al., 2000:131; CONANP, 2002:141; Pacheco-Ruíz and 

Zertuche-González, 2002:468; Mateo-Cid et al., 2006:56; Y.-P. Lee, 

2008:416, figs. A–E; Pacheco-Ruíz et al., 2008:210.

Corallopsis excavata Setchell et N. L. Gardner, 1924:756, pls. 23: figs. 24, 

25, 44b, 48.
458 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

FIGURE 229. Lomentaria catenata: A. Habit of tetrasporophyte, note characteristic swollen branchlets with 

sunken tetrasporangial sori (JN-5899, US Alg. Coll.-160462). B. Female gametophyte with protruding cystocarps 

(JN-5899, US Alg. Coll.-160463).
NUMBER 96 • 459

Taylorophycus laxa sensu Norris, 1973:11, pl. 4; Pacheco-Ruíz et al., 

2008:209 [non Taylorophycus laxa (W. R. Taylor) E. Y. Dawson, 

1961a:224].

Algae mostly 8–14 cm tall, dark red, of few to many erect, 

semicartilaginous, terete axes; multifariously branched, up 

to 3–5 orders, opposite, whorled or alternate; axes 1–2 mm 

in diameter, occasionally laterally fused; branches sometimes 

constricted at regular intervals forming fusiform segments, 

0.7–1.0 mm in diameter, 2.5–7.0 mm long; attached by a discoid holdfast that produces horizontally growing stolons that 

attach by small discs at irregular intervals. Cortex and medulla 

in transection 120–160 μm thick, surrounding a central hollow, mucilage-filled cavity. Cortex of 1(–2) layers; outermost 

cortical layer of anticlinally elongated pigmented cells. Medulla 

of 4–6 rows of cells, 20–30 μm wide, 80–200 μm long; with 

a loose network of filaments lining the innermost medullary 

cells, bearing single or small groups of secretory cells, facing inward toward central hollow cavity. Branch constrictions solid, 

pseudoparenchymatous.

Tetrasporangia tetrahedrally divided, subspherical to oblong, up to 90 μm long, up to 60 μm in diameter, surrounded 

by a filamentous network; in sori submerged within depressions 

of the cortex of swollen branchlets; sori become open cavities, sometimes merging. Cystocarps spherical to urn shaped, 

750–900 μm in diameter, ostiolate; prominently elevated above 

branch surface; carposporangia 95–120 μm in diameter. Spermatangia not observed in Gulf specimens; as reported elsewhere: 

on bladder-like spermatangial branchlets. Spermatangia 1–2 terminal and subterminal on parent cell; spermatia elongated, 4.6 

μm long, 3.2 μm in diameter (after I. K. Lee, 1978).

Habitat. On rocks; low intertidal to shallow subtidal, down to 6 m depths.

Distribution. Gulf of California: Puerto Peñasco 

to El Coloradito; Isla San Jorge to Guaymas; Isla de Tortuga 

(NE of Isla San Marcos) to Isla San Esteban; Bahía de Loreto. 

Eastern Pacific: Punta Santa Rosaliita (“Punta Santa Rosalía”), 

Baja California to Isla Magdalena (Bahía Magdalena), Baja California Sur; Isla Cedros. Western Pacific: China; Korea; Japan.

Type Locality. Shimoda (near southern end of Izu 

Peninsula), Shizuoka Prefecture, Japan (Harvey, 1860; Dawson, 

1959b).

Remarks. Lomentaria catenata is a perennial species 

in Japan (I. K. Lee, 1978). In the northern Gulf L. catenata attains its largest sizes in summer and is apparently absent by fall 

(Dawson, 1963a). Though of similar dimensions, L. catenata is 

more rigid, generally darker red, and has constricted segments, 

whereas L. hakodatensis is flaccid, lighter and more purple in 

color, and has constrictions only at the base of the branches.

Lomentaria hakodatensis Yendo

FIGURE 230

Lomentaria hakodatensis Yendo, 1920:6; Dawson, 1944a:308, pl. 75: 

fig. 2; 1950d:341; 1951:56; 1953c:3; 1960a:48; 1960c:97; Dawson et al., 1960b:24; Dawson, 1961b:437; 1962c:278 ; 1963a:466, 

pl. 86: fig. 2; pl. 95: figs. 1, 2; Dawson and Neushul, 1966:180; Abbott and North, 1972:76; Abbott and Hollenberg, 1976:569, fig. 

516; I. K. Lee, 1978:108, figs. 42–52, pl. 5: figs. A–C; I. K. Lee and 

West, 1980:419; Tseng, 1983:122, pl. 64: fig. 4; Stewart and Stewart, 

1984:144; Hawkes and Scagel, 1986:332; Scagel et al., 1989:206; 

Stewart, 1991:122; Serviere-Zaragoza et al., 1993a:484; León-Tejera 

et al., 1993:200; Mateo-Cid et al., 1993:48; González-González et 

al., 1996:242; Yoshida, 1998:837, fig. 3–77E; Abbott, 1999:224, fig. 

62A–D; Xia and Zhang, 1999:156, fig. 90, pl. 9: fig. 2; Mateo-Cid et 

al., 2000:66 [with query]; Abbott et al., 2002:310; Y.-P. Lee, 2008:418, 

figs. A–C; Pacheco-Ruíz et al., 2008:210; Bernecker, 2009:CD-Rom p. 

64; Fernández-García et al., 2011:62.

Lomentaria sinensis M. Howe, 1924:139, pl. 1: fig. 1; Tseng and Li, 

1935:221; Okamura, 1936:684.

Hooperia baileyana sensu Setchell et N. L. Gardner, 1930:153 [non Hooperia baileyana J. Agardh, 1896:89, which is now Lomentaria baileyana

(Harvey) Farlow, 1876:698].

Algae erect, mostly 3–9 cm tall, reddish purple to greenishpurple, often forming bushy clumps, of flaccid, gelatinous, terete 

to compressed axes and branches, narrow (0.5–)0.8–1.3 mm in 

diameter, branching opposite, sometimes somewhat whorled or 

irregularly alternate, to 3–5 orders; prostrate basal portion of entangled stoloniferous axes, 0.7–1.3 mm in diameter, attached to 

each other and to substratum by numerous discs. Branches slightly 

to barely constricted at base (most evident at base of ultimate 

FIGURE 230. Lomentaria hakodatensis: Habit (EYD-10896, US 

Alg. Coll.-12228).
460 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

branchlets), gradually tapering upward to apex; branches may be 

laterally adjoined at various contacts. Thallus wall 75–125 μm 

thick in transection; transverse septa composed of 3–4 irregularly 

arranged cell rows. Cortex of 1(–2) cell layer; cortical cells oblong 

to elliptical, 17–24 μm long, 10–15(–19) μm in diameter. Medulla 

of 3–4 cell layers; cells more or less isodiametrical, up to 50–60 

μm in diameter, inward becoming wider than tall; hollow cavity 

lined with a few slender elongated filaments, these bearing occasional gland cells, single or in aggregations.

Tetrasporangia tetrahedrally divided, subspherical, 90–110 

μm long, 95–125 μm in diameter; borne in swollen fusiform branchlets within cavities (100–400 μm wide) in the cortex; filamentous 

cells among the tetrasporangia are poorly developed. Carpogonial 

branch 3-celled. Gonimoblast and auxiliary cells form a fusion cell, 

trunk-like column in shape. Cystocarps sessile, 700–1000 μm in diameter, with 1(–2) ostiole; scattered in upper portions of branches; 

carpospores 90–100 μm in diameter. Spermatangium terminal, 1 

on parent cell; in superficial sori on somewhat swollen branches 

(in surface view appearing more or less reticulate, or circular in 

arrangement about basal cell); spermatia 4.5 μm long, 2.9 μm in 

diameter (reproduction after I. K. Lee, 1978).

Habitat. On rocks and sometimes other algae; low 

intertidal to subtidal, down to 20 m depths.

Distribution. Gulf of California: Puerto Refugio, 

Isla Ángel de la Guarda to Bahía Empalme (south of Guaymas); 

Bahía Concepción to Cabo Pulmo; Nayarit to Jalisco. Eastern 

Pacific: southern British Columbia to Oregon; Anacapa Island 

(California Channel Islands) to La Jolla, California; Isla Guadalupe and Islas San Benito (off Baja California); Bahía San Quintín 

(Baja California ) to Punta Lobos (near Todos Santos, Baja California Sur); Colima to Guerrero; Costa Rica. Central Pacific: Hawaiian Islands. Western Pacific: China; Korea; Japan; Vietnam.

Type Locality. Seven localities: “Hakodate, Otaru, 

insulam Rishiri, prov. Hidaka, prov. Inaba, prov. Bōshū, prov. 

Owari” (Yendo, 1920:6). Lectotype locality: Hakodate, Hokkaidō

Pref. (Oshima subpref.), Hokkaidō, Japan (I. K. Lee, 1978).

Remarks. A Japanese species, Lomentaria hakodatensis was first reported in the Gulf of California by Dawson 

(1944a). Hawkes and Scagel (1986) suggested that L. hakodatensis from Vancouver Island to Washington state may have 

been introduced with oysters imported from Japan. It apparently 

has also been similarly introduced in northern France (Cabioch 

and Magne, 1987), Spain (Bárbara and Cremades, 1996), Italy 

(Curiel et al., 2006), California (Miller, 2004), Russia, Hawaii 

(Abbott, 1999), and Australia (Millar and Kraft, 1993; Miller et 

al., 2011). It can be invasive: since being recorded in Humboldt 

Bay, northern California, it has increased in abundance (Miller 

et al., 2011). While L. hakodatensis is not presently a problem in 

the northern Gulf of California, it should be monitored.

Culture studies of Lomentaria hakodatensis, an annual 

western Pacific species (I. K. Lee, 1978), from Korea (I. K. Lee 

and West, 1980) showed a triphasic life history of isomorphic 

tetrasporophytes and gametophytes.

Rhodymeniaceae

Rhodymeniaceae Harvey, 1849a:75, 120; Saunders et al., 1999:35.

Algae are erect; axes and branches are terete to flat, strap-like 

to foliose, and some genera have hollow, mucilage-filled vesicles. 

Thalli may be alternately, pinnately, palmately, dichotomously to 

polychotomously, or irregularly branched. Multiaxial in construction, species may be solid or partially solid and partially hollow. 

Anatomically, they lack longitudinal medullary filaments. The 

medulla may be pseudoparenchymatous, composed of compact 

large cells; in others the medulla may become hollow or partially 

solid and hollow. The cortex is composed of (1–)2–4(–6) cell layers, with cells often in anticlinal rows. Secretory cells (gland cells) 

occur in some members and can be solitary or in groups.

Gametophytes and tetrasporophytes are isomorphic. Tetrasporangia are usually cruciately divided, intercalary (or rarely 

terminal) on cortical filaments. The gametophytes of most members are dioecious, while some have monoecious gametophytes. 

Carpogonial branches are four-celled or rarely (two) three-celled. 

Auxiliary cell filaments of two or three cells develop before fertilization and are borne on the supporting cell of the carpogonial 

branch (procarpic). Auxiliary cells usually do not fuse with other 

cells. Cystocarps are generally compact, more or less globose, 

partly immersed, and prominently protruding and scattered over 

the thallus surface, with a pericarp that either has or lacks an 

ostiole. Most of the gonimoblast cells become carposporangia, 

and the fusion cell is elongate (fusing cells still discernible), and 

tela arachnoidea are absent. Spermatangia are cut off from initials formed from the outer cortical cells and are superficial and 

scattered over the outer cortex or in sori.

The family is represented by three of its genera in the northern Gulf of California.

KEY TO THE GENERA OF RHODYMENIACEAE IN THE NORTHERN GULF OF CALIFORNIA

1a. Algae with vesicle-like laterals that are internally hollow and filled with watery mucilage, above a solid, narrow stipe or 

a solid stipe and solid axes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Algae without hollow, mucilage-filled vesicular laterals, internally with a solid pseudoparenchymatous medulla 

throughout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Rhodymenia

2a. Axes terete, solid, simple to branched, above a solid stipe, that bear hollow (mucilage filled) spherical to pyriform, sometimes elongated or saccate, unbranched vesicular laterals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Botryocladia

2b. Axes and branches of hollow (mucilage filled), elongated, saccate vesicles that bear similar hollow, lobed vesicles, borne 

above a usually short, solid stipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Irvinea
NUMBER 96 • 461

Botryocladia (J. Agardh) Kylin

Chrysymenia sect. Botryocladia J. Agardh, 1851:214, nom. cons.

Botryocladia (J. Agardh) Kylin, 1931:17.

Botryocladia (J. Agardh) Harvey, 1853:249, nom. rej.

Algae are erect, deep pink, dark rosy-reds to orange-brown 

in color, composed of solid, terete, branched or unbranched 

axes bearing inflated, hollow, mucilage-filled, vesicle-like laterals; above a discoid or rhizomatous holdfast. Solid axes are internally compact, of large, nearly colorless, medullary cells that 

grade into a cortex of small, pigmented cells. The vesicle-like 

laterals are variously shaped; spherical, ovoid, pyriform, or saccate. At the interior of the vesicles is a hollow cavity (without a 

filamentous medulla) filled with a watery mucilage. Vesicle walls 

have a cortex of 2–3(–6) layers of small cells over a layer(s) of 

relatively larger rounded medullary cells bordering the hollow 

interior. The outermost cortical layer of the vesicles may be continuous or discontinuous. If the cortex is incomplete, it appears 

net-like in surface view, with the small pigmented cells arranged 

in open rosettes (circular arrangement) around and above the 

medullary cells. However, in some species the vesicle cortical 

layer is net-like and incomplete initially, but later cortical cells 

fill in the open areas, resulting in a complete cortical layer at 

maturity. The medulla is one to three cell layers; inner medullary 

cells are oblong to polygonal and bear secretory cells (“gland” 

cells) singly or in groups, that project into the mucilage-filled 

cavity. Secretory cells may be sessile on unmodified medullary 

cells or borne on special initials.

Asexual reproduction has been reported in all the rhizomatous species. Life histories are presumed to be triphasic, with 

isomorphic tetrasporophytes and gametophytes. Tetrasporangia 

are regularly or irregularly cruciately divided, formed in an intercalary position in the cortical layers, and scattered over the 

vesicles. Gametangial thalli are dioecious or monoecious. The 

carpogonial branch is four-celled. Most gonimoblast cells become carposporangia, developed in two to three lobes inside a 

thick pericarp. Cystocarps are ostiolate, without ornamentation, 

and scattered over the vesicles; they are immersed within or protruding above the vesicle surface (cortex thickens over cystocarp) 

and inward into the medulla. Spermatangia are in superficial 

sori, scattered over the vesicle surface; spermatia are terminal on 

elongated initials developed from cortical cells.

Remarks. Species of Botryocladia are easily recognized in the field by their distinctive, mucilage-filled, vesicle-like 

(often “grape-like” in appearance) laterals borne on solid, terete stalks and branches. These characters separate Botryocladia 

from the completely saccate or vesiculate thalli of Chrysymenia 

J. Agardh (1842), which lack a solid stipe. The lack of branching in the vesicles of most Botryocladia species is the primary 

field character used to distinguish the genus from the recently 

described Irvinea Guiry (in Saunders et al., 1999) that has vesiculate branches that further develop vesicular branches (compound). The function of the “gland cells” in this genus was 

found to be secretory (Young, 1978), and they are now generally 

referred to as secretory cells.

The Pacific Mexico species, Botryocladia adhaerens E. Y. 

Dawson (1963a:449, pl. 82: figs. 1–3), described from Rocas 

Alijos off Pacific Baja California Sur, is composed of elongated 

vesicles, with the primary vesicle issuing one or more secondary 

vesicles, thus exhibiting some of the morphological characteristics of Irvinea. However, with vesicles that have an “essentially 

continuous outer layer” (Dawson, 1963a), B. adhaerens cannot 

be transferred to Irvinea until additional reproductive or morphological features can be found and molecular data can be 

acquired to elucidate its generic status. Another similar species, 

Botryocladia chiajeana (Meneghini) Kylin (1931, basionym: 

Chrysymenia chiajeana Meneghini, 1844b; see also AfonsoCarrillo et al., 2006), is also recorded from Rocas Alijos (Silva 

et al., 1996b).

The oligosaccharides, compounds derived from sulfated 

polysacchardies, of western Atlantic Botryocladia occidentalis

(Børgesen) Kylin (1931) have been shown to have anticoagulant 

activity (Farias et al., 2000; Pereira et al., 2005; Jiao et al., 2011) 

and anti-venom activity (Toyama et al., 2010). The biological 

activities of chemical compounds of northern Gulf of California 

species of Botryocladia have not yet been investigated.

There are three species of Botryocladia in the northern Gulf 

of California.

KEY TO THE SPECIES OF BOTRYOCLADIA AND IRVINEA IN THE NORTHERN GULF OF CALIFORNIA

1a. Vesicles bearing secondary vesicles (compound); vesicles large, elongate; thalli with a short, solid stipe . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Irvinea hancockii

1b. Vesicles not bearing additional vesicles (simple); vesicles spherical, globose, ovoid, or pyriform; vesicles borne on solid, 

terete, branched axes above the stipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

2a. Outermost cortical layer of vesicles not continuous, appearing net-like, arranged in open rosettes over inner cells . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Botryocladia guaymasensis

2b. Outermost cortical layer continuous over vesicle surface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

3a. Vesicles subspherical, numerous, densely set along entire length of axes; less than 4 mm in diameter and up to 6 mm in 

length . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Botryocladia uvarioides

3b. Vesicles mostly longer than wide; larger than 4 mm in diameter and longer, up to 17 mm in length . . . . . . . . . . . . . . . . 

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Botryocladia datilensis
462 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Botryocladia datilensis (E. Y. Dawson) J. N. Norris, comb. nov.

FIGURE 231

Botryocladia pseudodichotoma var. datilensis E. Y. Dawson, 1944a:305, 

pl. 45: fig. 7, pl. 73: fig. 1 [type specimens]; 1961b:436; GonzálezGonzález et al., 1996:178.

Botryocladia uvarioides sensu Dawson, 1963a[in part; only specimens of B. 

pseudodichotoma var. datilensis]:454, pl. 82: only fig. 4 [non Botryocladia uvarioides E. Y. Dawson, 1944a:306].

Algae erect, 3–8 cm tall; composed of solid, terete branched 

axes that bear subspherical to elongate, unbranched vesicles, 

mostly 5–17 mm long, 4–6 mm in diameter, each above a very 

short pedicel, about 0.5 mm long; thalli attached by a small discoid holdfast. Vesicles with a complete outermost cortical layer 

of small, pigmented cells, continuous over larger inner cells. Secretory cells 30–35 μm long; mostly borne in groups of 5–6 on 

innermost medullary cells facing inward toward cavity.

Reproduction not described (although a tetrasporophyte 

was reported by Dawson, 1944a:305).

Habitat. On rocks, in crevices, and in tide pools;

low intertidal to shallow subtidal.

Distribution. Gulf of California: Isla Tiburón; Isla 

Turner; Guaymas.

Type Locality. Isla Turner (El Datil; Turners Island), off southeast end of Isla Tiburón, Islas de la Cintura, Gulf 

of California, Mexico.

Remarks. Although Dawson (1963a:455, as B. 

pseudodichotoma var. datilensis) seemed less certain of its taxonomic separation from B. uvarioides, B. datilensis is recognized 

as distinct from the other known Gulf of California species of 

Botryocladia and the California B. pseudodichotoma (Farlow) 

Kylin (1931).

Botryocladia guaymasensis E. Y. Dawson

FIGURE 232

Botryocladia guaymasensis E. Y. Dawson, 1963a:451, pl. 82: fig. 11, pl. 84 

[holotype]; González-González et al., 1996:178.

Algae erect, up to 15 cm tall, attached below by a relatively 

small discoid holdfast. A solid, terete, irregularly branched main 

axis bears numerous, ovoid, unbranched elongate vesicles, mostly 

4–12(–14) mm long and 2–5 mm in diameter (at mid vesicle), 

borne on short pedicels, 0.5–1.0 mm long. Vesicle walls composed 

of an inner layer of thin-walled, elliptical medullary cells, 50–

150 μm wide, that bear secretory cells, 15–25 μm long, extending 

into the cavity. Outermost cortical layer of vesicles discontinuous 

FIGURE 231. Botryocladia datilensis: A. Habit (JN-2993, US Alg. Coll.-158661). B. Surface view of portion of vesicle showing continuous 

outer cortical layer, underlying polygonal pattern of larger medullary cells, and one group of secretory cells. C, D. Groups of secretory cells 

(darkly stained) on cells of the inner wall of vesicles (B–D, JN-4429, US Alg. Coll. microscope slide 4589).
NUMBER 96 • 463

(in surface view); small surface cells, 6–10 μm in diameter, and an 

underlying secondary layer of larger, pigmented cells (subcortical 

cells), 20–25 μm in diameter, together form a network of open 

rosettes over medullary cells (Figure 232C). Secretory cells sessile, 

usually sparse to few, either solitary or in groups of 2–6.

Tetrasporangia ovoid, 25–30 μm long; scattered in cortex 

over distal portions of vesicles. Cystocarps about 500 μm in diameter; protruding from and scattered over vesicle walls. Spermatangia not known.

Habitat. On rocks; low intertidal to shallow subtidal, down to 15 m depths.

Distribution. Gulf of California: Playa Las Conchas (Playa Estación), Puerto Peñasco to Punta Robinson (vicinity of Puerto Libertad); Bahía San Carlos to Guaymas.

Type Locality. Bahía San Francisco, within east 

shore of Bahía San Carlos (about 11 km [~7 mi] northwest of 

Guaymas), Sonora, Gulf of California, Mexico.

Botryocladia uvarioides E. Y. Dawson

FIGURE 233

Botryocladia uvarioides E. Y. Dawson, 1944a:306, pl. 45: figs. 8–10, pl. 

75: fig.1 [type specimen]; 1959a:28, fig. 8; 1961b:436; 1963a:454 

[in part; excluding specimens of B. pseudodichotoma var. datilensis], pl. 82: figs. 9, 10, pl. 83: fig. 3; 1966a:25; Norris, 1973:14, pl. 

5; Huerta-Múzquiz, 1978:338; Mateo-Cid and Mendoza-González, 

1992:21; Mendoza-González and Mateo-Cid, 1992:20; ServiereZaragoza et al., 1993a:483; Mateo-Cid and Mendoza-González, 

1994b:40; Mendoza-González et al., 1994:108; González-González 

et al., 1996:179, fig. 21; Mateo-Cid et al., 2000:65; Cruz-Ayala et 

al., 2001:191; CONANP, 2002:141; Pacheco-Ruíz and ZertucheGonzález, 2002:468; Mateo-Cid et al., 2006:56; Pacheco-Ruíz et al., 

2008:210.

Botryocladia pseudodichotoma sensu Taylor, 1945:255 [in part; non Botryocladia pseudodichotoma (Farlow) Kylin, 1931:18; basionym: Chrysymenia pseudodichotoma Farlow, 1889:1].

Algae erect, up to 22 cm tall, with solid axes and branches, 

up to about 1 mm in diameter, above a solid stipe, dividing into 

axes that branch irregularly up to 5 orders; dense, with numerous, subspherical mucilage-filled vesicles, closely set along entire 

solid axes and branches. Subspherical vesicles 2–4(–6) mm in diameter; each on a short pedicel; vesicle wall of 3 cell layers with 

hollow, mucilage-filled cavity. Outermost cortical layer of vesicles with small cells, 4–6 μm in diameter, continuous over vesicle 

surface; subcortical cells 12–18 μm in diameter; innermost cells 

larger, 50–90 μm in diameter. Secretory cells relatively rare to 

infrequent, sessile, either solitary, 10–12 μm in diameter, mostly 

1(–2) (if 2, not close together) on an inner cell (Figure 233B), or 

still sparse but occasionally in groups of 3–5 (Figure 233B), with 

a slender attachment between them; borne on inward-facing surface of innermost medullary cells.

Tetrasporangia 20–25 μm in diameter, scattered over the 

vesicles. Gametangial thalli not seen.

FIGURE 232. Botryocladia guaymasensis: A. Habit (JN-6083b, US Alg. Coll.-158697). B. Habit, cystocarpic specimen (JN-5858, US Alg. 

Coll.-158696). C. Surface view of vesicle wall showing the incomplete outer cortical layer that forms a network of rosettes around the inner cells 

(JN-4847, US Alg. Coll. microscope slide 4588).
464 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Habitat. On rocks, in crevices, and in tide pools;

mid intertidal to subtidal; also dredged from 40 m depth (Dawson, 1944a).

Distribution. Gulf of California: Puerto Peñasco to San José del Cabo; Mazatlán, Sinaloa to Jalisco; 

Isla María Magdalena, Islas Marías (Islas Tres Marías). Eastern Pacific: Playa Los Cerritos (south of Todos Santos), Baja 

California Sur.

Type Locality. San José del Cabo, Baja California 

Sur, southern entrance to Gulf of California, Mexico.

Uncertain Record:

Botryocladia pseudodichotoma (Farlow) Kylin

Botryocladia pseudodichotoma (Farlow) Kylin, 1931:18; Mendoza-González 

and Mateo-Cid, 1986:424.

Remarks. Specimens reported as “Botryocladia 

pseudodichotoma” from Isla Tiburón and estero Punta Perla 

(Mendoza-González and Mateo-Cid, 1986) need to be reexamined to verify the presence of this species in the northern 

Gulf.

Irvinea Guiry in G. W. Saunders, 

I. M. Strachan et Kraft

Irvinea Guiry in G. W. Saunders, I. M. Strachan et Kraft, 1999:36.

Algae are erect, consisting of solid, terete, branched stipes 

that bear elongated, cylindrical or saccate vesicles that branch 

or bear secondary vesicles that are formed sympodially and are 

irregularly arranged. Thalli are attached below by a branched 

stoloniferous holdfast that coalesces to form a discoid structure 

and may issue additional erect axes. Thalli are multiaxial in construction; with a cortex of two to three layers of small cells that 

initially form a discontinuous layer over the medullary cells, arranged in open rosettes. The medulla is composed of 1–2 layers 

of larger rounded cells. Vesicles appear hollow and are filled with 

a mucilage that is likely produced by the secretory cells. Secretory cells are singular or in groups of two to six, borne on special 

support structures (unique, rotund, bearing cells sensu Dawson 

and Neushul, 1966, or “special initial” sensu Guiry and Guiry, 

2009) that develop on the inner faces of the medullary cells lining the cavity.

FIGURE 233. Botryocladia uvarioides: A. Habit (JN-3145, US Alg. Coll.-217353). B. Secretory cells on inner medullary cells facing into the 

hollow cavity (drawn from syntypes after Dawson, 1944a: pl. 45: figs. 8–10).
NUMBER 96 • 465

Life histories, where known, involve isomorphic tetrasporophytes and gametophytes. Tetrasporangia are cruciately divided, developed in an intercalary position from cortical cells 

within irregularly shaped sori on the vesicles. Gametophytes are 

dioecious. Four-celled carpogonial branches are borne on innercortical supporting cells that also bear a two-celled auxiliary cell 

branch. The carposporophyte develops outwardly from a basal 

fusion cell and forms two to three developing lobes of carposporangia in different stages of maturity; a few slender, elongate 

cells, perhaps with a nutritive function, persist in the mature 

ostiolate cystocarp. Cystocarps, with a thick pericarp, protrude 

from and are scattered over vesicles. Spermatangia in sori cover 

most of a vesicle, cut off from elongate initials formed from cortical cells.

Remarks. Molecular systematic studies revealed that 

Botryocladia ardreana J. Brodie et Guiry (1988) and some other 

species referred to Botryocladia belong in a segregate genus, Irvinea (generitype: I. ardreana (J. Brodie et Guiry) Guiry in Saunders et al., 1999; Wilkes et al., 2006). Morphological characters 

used to separate Irvinea from related genera (Guiry in Saunders 

et al., 1999; Wilkes et al., 2006; Guiry and Guiry, 2009) include 

strongly protruding cystocarps and vesicles with an incomplete 

outer cortex (i.e., arrangement of cortical cells in rosettes, at least 

initially) in combination with the formation of secretory cells on 

special initials (bearing cells). However, because of features that 

overlap with some species of Botryocladia, it is difficult to distinguish Irvinea solely on morphological characters (e.g., Schneider and Lane, 2000, 2008), and Afonso-Carrillo et al. (2006) 

concluded Irvinea was only separable on molecular evidence. 

Schneider and Lane (2008) suggested that a characteristic for Irvinea might be its vesicle with branched or secondary vesicles of 

indeterminate growth, whereas the few species of Botryocladia

with branched vesicles have determinate growth.

Currently, there is one species of Irvinea known in the 

northern Gulf of California. (See “Key to the Species of Botryocladia and Irvinea.”)

Irvinea hancockii (E. Y. Dawson) R. Wilkes, L. McIvor et 

Guiry

FIGURE 234

Botryocladia hancockii E. Y. Dawson, 1944a:305, pl. 45: figs. 2–5; 

1961b:436; 1963a:452, pl. 82: figs. 6–8, 12; Dawson and Neushul, 

1966:180, pl. 43: figs. 1–3; Norris and Bucher, 1976:18, fig. 6b; Abbott and Hollenberg, 1976:551, fig. 495; González-González et 

al., 1996:178; CONANP, 2002:141; Pacheco-Ruíz and ZertucheGonzález, 2002:468; Pacheco-Ruíz et al., 2008:210.

Irvinea hancockii (E. Y. Dawson) R. Wilkes, L. McIvor et Guiry, 2006:488.

Algae erect, 3–15 cm tall; thalli composed of hollow, broad, 

elongated primary main axis that bears radially arranged lobed 

to elongated saccate vesicles, 4–6 mm in diameter, with few to 

many elongated secondary vesicles, that in turn may further produce more lobed protuberances or elongated saccate vesicles. 

Primary elongate vesicle borne above a short, solid, branched, 

terete stipe, about 1.0–1.5 mm in diameter; attached below by 

a small discoid holdfast. Vesicle wall of 3 cell layers, outermost 

cortical layer is discontinuous, appearing net-like in surface view, 

with small cells arranged in open rosettes over inner cells. Secretory cells occasional, borne from a distinctive rotund bearing cell 

(“special initial” sensu Guiry and Guiry, 2009) issued from large 

cells of the inner medulla bordering the cavity. Secretory cells 

pyriform to subspherical, either single or in groups of 2–6.

Tetrasporophytes unknown. Cystocarps hemispherical, protruding, about 300 μm tall and 600 μm in diameter, with an 

ostiole, 50 μm in diameter. Spermatangia not known.

Habitat. On rocks; subtidal, 8–19 m depths; also 

dredged from 20–40 m depths (Dawson, 1944a).

Distribution. Gulf of California: Isla Mejía 

(northwest side of Puerto Refugio, Isla Ángel de la Guarda) to 

Isla Estanque; Bahía Agua Verde to Punta Los Frailes. Eastern 

Pacific: Anacapa Island (California Channel Islands) to Bahía Sebastián Vizcaíno (Baja California Sur).

Type Locality. Bahía Agua Verde, Baja California 

Sur, Gulf of California, Mexico.

Remarks. Irvinea hancockii can be recognized in 

the Gulf primarily by its short solid stipe and very elongated, 

more or less tubular, saccate axes and branches. These characters 

separate I. hancockii in the field from the Gulf species of Botryocladia, which have subspherical to pyriform vesicles on solid, 

slender, terete axes and branches.

Rhodymenia Greville

Rhodymenia Greville, 1830: xlviii, 84, pl. 12 [as “Rhodomenia”]; Sparling, 

1957:353.

Rhodymenia (Greville) Montagne, 1841:151.

Epymenia Kützing, 1849:787; Womersley, 1996:69; Saunders et al., 1999:37.

Algae are erect or partially prostrate, composed of flattened, 

semicartilaginous, ligulate to foliose fronds that may be simple 

but are usually dichotomously, palmately, or irregularly branched. 

Fronds are attached to substratum by a basal disc or stolons. 

Blades sometimes have marginal, surface, or apical proliferations, 

and some are perforated (not known in Gulf species). Many species are sessile (without a terete stipe); some have a short to long, 

simple or branched stipe above a discoid holdfast, and others arise 

and spread from terete stoloniferous basal branches that are secondarily attached by small discs. Growth in some species is monopodial and in others is ramisympodial. Thalli are multiaxial in 

structure, with a pseudoparenchymatous medulla, composed of 

a few to many layers of large, nearly colorless, isodiametric cells. 

The cortex is thin, of two to five layers of progressively smaller 

cells, the outermost of which is pigmented and axially elongated.

Life histories are incompletely known but are presumed 

to be isomorphic. Tetrasporangia are cruciately divided, developed in an intercalary position within the unmodified cortex, 

and either (1) scattered over the blade, (2) in subapical sori, or 

(3) formed in special proliferations. Gametangial thalli are dioecious. Carpogonial branches (three-)four-celled, borne on a 

large, multinucleate supporting cell that also bears a two-celled 
466 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

auxiliary cell branch (procarpic). The gonimoblast develops outward, often creating two to three compact gonimolobes, with 

almost all cells becoming carposporangia; tela arachnoidea (network of spiderweb-like filaments between the gonimoblast and 

pericarp) are absent. Cystocarps with a basal fusion cell and a 

thick ostiolate pericarp, they are hemispherical, large, and protruding, and they occur scattered over the upper portion of 

blades. Spermatangia are cut off from outer cortical cells and 

occur in small subapical sori or in larger irregular patches, scattered over blades.

FIGURE 234. Irvinea hancockii: Habit of a cystocarpic thallus; note short, solid, terete stipe from which the large elongate, cylindrical vesicles 

of the main axis arise and elongate vesicle branches from axial vesicles (JN-5600, US Alg. Coll.-217355).
NUMBER 96 • 467

Remarks. Rhodymenia species occur worldwide and 

are know from low intertidal to depths of 100 m (Guiry and 

Guiry, 2009).

There are four species of Rhodymenia known in the northern 

Gulf of California. One additional species, Rhodymenia californica

Kylin (1931), has been reported in the southern Gulf from Punta 

Arena (Mateo-Cid et al., 2000) and in Pacific Mexico (Pacheco-Ruíz 

and Aguilar-Rosas, 1984; R. Aguilar-Rosas et al., 1990; Dreckmann et al., 1990; Serviere-Zaragoza et al., 1993a; Mateo-Cid and 

Mendoza-González, 1994b; Riosmena-Rodríguez et al., 2005b).

KEY TO THE SPECIES OF RHODYMENIA IN THE NORTHERN GULF OF CALIFORNIA

1a. Blades above a distinct terete stipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

1b. Blades sessile, arising directly from holdfast (lacking a stipe) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2a. Blade segments less than 3 mm wide (0.7–2.5 mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . R. dawsonii

2b. Blade segments wider than 4 mm (4–7 mm) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . R. hancockii

3a. Blades markedly divaricately, dichotomously to irregularly branched; segments 2–3 mm wide . . . . . . . . . R. divaricata

3b. Blades dichotomously branched at narrow angles; segments 3.5–4 mm wide . . . . . . . . . . . . . . . . . . . . . . . . . R. huertae

Rhodymenia dawsonii W. R. Taylor

FIGURE 235A,B

Rhodymenia dawsonii W. R. Taylor, 1945:251, pl. 84: fig. 2; Dawson et 

al., 1960b:24; Dawson, 1961b:436; 1963a:459, pl. 88; MendozaGonzález and Mateo-Cid, 1985:32; González-González et al., 

1996:266.

Rhodymenia arborescenssensu Dawson et al., 1960a:76 [in part]; Dawson et 

al., 1960b:22 [in part]; Pacheco-Ruíz et al., 2008:210 [non Rhodymenia arborescens E. Y. Dawson, 1941b:149].

Rhodymenia hancockii sensu Dawson, 1959a:28, fig. 9A [non Rhodymenia 

hancockii E. Y. Dawson, 1941b:146].

Fronds dull to bright red in color, up to 12 cm tall, attached 

by a subconical, discoid holdfast; with a cylindrical stipe, 0.8–

1.2 mm in diameter, 2–5 cm long; upper end of stipe becoming 

compressed into dichotomously branched blade; repeatedly dichotomously branched, mostly branching at intervals of 5–12 

mm; blade segments (branches) very narrow, 1.5–2.5 mm wide 

in lower to mid blade, 0.7–1.0 mm wide in upper portions; with 

subacute apices. Initial stipe of primary axes may successively 

produce secondary stipitate axes from its upper portion. Segments of mid thallus 170–370 μm thick; medulla of 3–7 layers 

of large colorless cells, 30–70 μm in diameter, grading through 

3–5 layers of smaller cortical cells; outermost cortical cells anticlinally elongate, up to 6–7 μm in diameter.

Tetrasporangia ellipsoidal, 30 μm long; within small nemathecial sori, bordered by narrow sterile margin, on both sides 

of upper branch segments. Cystocarps prominent, primarily 

along margins in upper portions of thallus; subspherical, about 

750 μm in height and width, rostrate. Spermatangial thalli 

unknown.

Habitat. Subtidal; down to 16 m depths.

Distribution. Gulf of California: Isla San Pedro 

Nolasco; Bahía Agua Verde to Isla Cholla (off Isla Carmén); Isla 

San Francisco. Eastern Pacific: Arrecife de Sacramento (southsoutheast of Isla San Gerónimo, Baja California) to Isla Magdalena (Baja California Sur).

Type Locality. Dredged; off Cabo San Lázaro, 

about 5.6 km (~3.5 miles) north of Punta Hughes, Baja California Sur, Pacific Mexico.

Rhodymenia divaricata E. Y. Dawson

FIGURE 235C

Rhodymenia divaricata E. Y. Dawson, 1941b:141, pl. 23: fig. 31; 1944a:307; 

Taylor, 1945:251; Dawson, 1961b:436; 1963a:460, pl. 89: fig. 2; 

Norris, 1985d:214; González-González et al., 1996:267; CONANP, 

2002:141; Pacheco-Ruíz et al., 2008:210.

Fronds 3–5 cm tall; blades expanded directly above attachment (lacking a distinct stipe); irregularly dichotomously 

branched at 3–12 mm intervals, strongly divaricate; blade 

FIGURE 235. Species of Rhodymenia. A, B. Rhodymenia dawsonii:

Habits (EYD-18658, US Alg. Coll.-13019).C. Rhodymenia divaricata: Holotype (EYD-53-40; AHFH-1, now UC).
468 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

segments 2–3 mm wide, 200–300 μm thick; apices broadly 

rounded (lobe-like). Medulla of 5 layers of large cells, largest 

about 50 μm in diameter; outer medulla grading in size into cortex of 1–2 layers of smaller cells, 8–10 μm in diameter.

Reproductive structures unknown.

Habitat. On rocks and mud bottom; subtidal, 

3–10 m depths; dredged from 8–28 m depths.

Distribution. Gulf of California: Isla Mejía 

(northwest side of Puerto Refugio, Isla Ángel de la Guarda) to 

Canal de San Lorenzo (off southern end of Isla Espíritu Santo). 

Eastern Pacific: Galápagos Islands.

Type Locality. On mud bottom, dredged from 

about 3.6–5.5 m (2–3 fathoms), Bahía Guaymas, Sonora, Gulf 

of California, Mexico.

Remarks. Rhodymenia divaricata, described from 

the Gulf of California, has also been reported in the eastern 

United States from North Carolina to Florida (Schneider and 

Searles, 1991). However, Dawes and Mathieson (2008) suggested most or all of these western Atlantic records may be 

Gracilaria galetensis Gurgel, Fredericq et J. Norris (2004).

Rhodymenia hancockii E. Y. Dawson

FIGURE 236

Rhodymenia hancockii E. Y. Dawson, 1941b:146, pl. 20: fig. 20; pl. 26: fig. 

38 [type specimen]; 1944a:307; 1961b:436; 1963b:461, pl. 89: fig. 1; 

1966a:25; 1966b:64, fig. 4A; Abbott and Hollenberg, 1976:557, fig. 

502; Norris, 1985d:214; Ramírez and Santelices, 1991:303; GonzálezGonzález et al., 1996:267; Pacheco-Ruíz and Zertuche-González, 

2002:468.

Dendrymenia hancockii (E. Y. Dawson) Santelices, 1989:340, 342, pl. MM: 

fig. 9.

Fronds dark red, firm in texture, up to 8 cm tall; blades 

usually dichotomously to subdichotomously divided, of segments 4.0–7.0(–10) mm wide, 150–400 μm thick, with broadly 

rounded apices; dichotomous-flabellate blade abruptly expanded 

at right to acute angles from a stout, thick, terete, sympodially 

branched stipe; basal attachment structure incompletely known. 

Medulla of several layers of large, somewhat irregular, roundish 

to oval cells, becoming progressively smaller into outer medulla 

of 1–2 cells and grading into cortical layer of 1–3 small cells.

Reproductive structures unknown.

FIGURE 236. Rhodymenia hancockii: A, B. Habit variations (A, JN-2938, US Alg. Coll.-160805; B, JN-4875, US Alg. Coll.-160814).
NUMBER 96 • 469

Habitat. On shell-hash bottom and probably other 

hard substrata; subtidal, down to 10 m depths or more; also 

dredged from about 38 m depth.

Distribution. Gulf of California: Puerto Peñasco 

to Isla Ángel de la Guarda. Eastern Pacific: southern California; 

Chile.

Type Locality. On shell bottom, dredged from 

38.4 m (21 fathoms); west side of Puerto Refugio, Isla Ángel de 

la Guarda, Islas de la Cintura, Gulf of California, Mexico.

Remarks. Dawson (1941b:46; 1963a:461) noted 

“lowest basal parts unknown” in the type specimen of the Gulf 

of California Rhodymenia hancockii. However the photograph 

of the type (Dawson, 1941b: pl. 26: fig. 38 [center specimen]; 

1963a: pl. 89: fig. 1) suggests attachment may be a basal, prostrate, stoloniferous axis. Dawson (1966b:64) noted his Puerto 

Peñasco specimens referred to “R. hancockii” had a “sympodial 

branched rather short stipe” with a “woody cone without any 

stolons.” Thus, more collections of each of these different forms 

of R. hancockii are needed for further study and elucidation of 

their basal attachments to clarify the species.

Rhodymenia huertae J. N. Norris, nom. nov.

Rhodymenia rosea E. Y. Dawson, 1941b:141, nom. illeg., pl. 23: figs. 32, 

33; 1944a:307; 1961b:437; 1963a:463 [with generic query]; GonzálezGonzález et al., 1996:267; Pacheco-Ruíz et al., 2008:210 [non Rhodymenia rosea Harvey, 1855:554, which is now Leptosomia rosea (Harvey) Womersley, 1996:103].

Fronds bright rose, arising directly from a simple holdfast 

(without a terete stipe), up to 7 cm tall; branching primarily dichotomous, branching at intervals of 1–2 cm; blade segments 

(2–) 3.5–4 mm wide, about 100 μm thick, with rounded apices; margins entire in upper portions and sparsely denticulate 

in lower portions; proliferous bladelets produced from denticulations along margins; bladelets narrow at base and remaining 

simple or often dichotomously branched. Medulla of 1–2 layers 

of large, thin-walled cells, 50–80 μm in diameter; medulla to cortex sharply delimited; outer cortex a single layer of small, flattened, thin-walled, pigmented cells, 5–9 μm in diameter; cortical 

cells angular in surface view.

Reproduction unknown.

Habitat. Subtidal; dredged from 12–22 m depths.

Distribution. Gulf of California: Isla Ángel de la 

Guarda; Isla Tiburón.

Type Locality. Isla Mejía, northwest side of Puerto 

Refugio, Isla Ángel de la Guarda, Islas de la Cintura, Gulf of 

California, Mexico.

Remarks. Rhodymenia huertae is given as the 

new name for R. rosea E. Y. Dawson (1941b), which is a later 

homonym of R. rosea Harvey (1855). It is named for the late 

Laura Huerta-Múzquiz (Professor, Escuela Nacional de Ciencias Biológicas, Instituto Politécnico Nacional, Mexico D. F.) 

in recognition of her contributions to our knowledge of the 

marine algae of Mexico, including Baja California and the Gulf 

of California (Calderón de Rzedowski and Rzedowski-Rotter, 

2000). It was my pleasure to have interacted with her during 

her visits to the Smithsonian National Museum of Natural 

History.

Dawson (1963b, as ?Rhodymenia rosea), noted some 

R. huertae superficially resembled some small forms of Gracilaria 

tepocensis (E. Y. Dawson) E. Y. Dawson (1962a; see also Norris, 

1985c), which was originally described as Rhodymenia tepocensis E. Y. Dawson (1941b). When reproductive material of Gulf

Rhodymenia huertae is found, its generic placement can be further elucidated and molecularly tested.

Acknowledgments

I again express my thanks to my professors of marine botany, Isabella Aiona Abbott 

(Stanford University, now at University of Hawaii), Michael Neushul, Jr. (University 

of California, Santa Barbara [UCSB]), Robert W. Hoshaw (University Arizona), and 

George T. Oberlander and Harry D. Thiers (San Francisco State University), and also to 

Demorest Davenport and Alfred W. Ebeling (UCSB) for their continued encouragement, 

advice, and support throughout my Gulf of California research. I give special thanks 

to the marine scientists of the University of Arizona, Robert W. Hoshaw, Donald A. 

Thomson, and John R. Hendrickson, and to J. Laurens Barnard (Smithsonian National 

Museum of Natural History), who supported my northern Gulf of California phycological research. I appreciated the use of Laboratorio de Biología Marina in Puerto Peñasco 

(shared facility of the Universidad de Sonora and University of Arizona) while I was 

serving as University of Arizona Resident Marine Biologist and Station Director. I particularly thank Carlos Peña, José Ramon Infante-León, Ramon Durazo, Fernando Montanez, Argelia González, Manuel Esper-Huerta, Christine A. Flanagan, and Richard C. 

Brusca and also those at the Unidad Experimental Peñasco of the University of Arizona 

Environmental Research Laboratory (ERL), notably David Moore (Station Manager), 

Carl N. Hodges (Director, ERL), Carl Hodge, and Jim Ure. I thank also the many people 

of Puerto Peñasco for making me welcome while I lived in Mexico, particularly Agustin 

Cortéz C. and Eugenio Zamorano and his family. 

During the course of this research, my travel, fieldwork, and scuba diving was 

supported by grants from the National Science Foundation (NSF-BMS-73-07000) and 

NOAA (04-5-158-20 8/75). Later support was received from the American Philosophical Society (Philadelphia), the National Museum of Natural History, Smithsonian Institution, and NSF-PEET grant DEB-0328491 and NSF-BS&I grant 0742437. Partial 

support for studies of the Peyssonneliales was provided in grants from the NSF Systematic Biology (DEB-0919508) and Slippery Rock University of Pennsylvania, College of 

Health, Environment (Science Grant in Aid of Research); studies of the Ceramiales, Corallinaceae, Gigartinales, and Gracilariales were supported by NSF Bioinventory grants 

(SI-DSCG-542079 and SI-DSGC-642079). 

Help in designing and equipping a four-wheel-drive truck for off-road use and landbased scuba operations came from Vic Hickey, Bill Issacson, and especially Gary Haden 

(Ventura, California), all of whom developed and allowed the rigorous testing of offroad prototype equipment. Advice and assistance on setting up the truck for land-based 

scuba and field work that could accommodate four divers (and dogs Cyril and Beau) and 
472 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

all the collection, scuba, photographic, and camping gear along 

with food, water, and fuel came from Whitney Baines (Monterey 

Peninsula College), Craig Askin (Tucson), and Norm Lammer 

(Marine Science Institute, UCSB), who also constructed much of 

the specialized field equipment.

Thanks are owed to William Fenical (UCSD, SIO, Chief 

Scientist) for the opportunity to participate on National Science 

Foundation–sponsored cruises of the Scripps Institution of Oceanography R/V Dolphin to the Gulf of California and the OR/V 

Alpha Helix to islands of Pacific Mexico. He and Robert Jacobs 

(UCSB), Valerie Paul (Smithsonian Marine Station at Fort Pierce), 

William Gerwick (UCSD, SIO), and Oliver McConnell (the latter three were students of Bill Fenical at the time) provided many 

hours of collecting, lab work on natural product chemistry, and 

interesting discussions; I am grateful to have shared many adventures with them. Earlier collections made during the Gulf of 

California cruise of M/Y Makrele were made possible by Paul V. 

Ammen and Moss Landing Marine Laboratories (California State 

Universities). Thanks are also owed to Dennis Divins (UCSB) for 

scuba training and support and continued friendship. The field 

work and collecting could not have been completed without the 

help of scuba diving partners Katina Bucher Norris, William 

Fenical, Howard Sleeper, William Gerwick, John Paul, George 

Boehlert, David Coon, David Moore, Jerry D. Kudenov, Mark 

Helvey, Whitney Baines, Valerie Paul, Bruce Howard, and Oliver 

McConnell, all of whom made one or more of the land-based and/

or ship-based surveys and assisted with logistics and collecting. It 

is a pleasure to thank Richard S. Felger (University Arizona), Richard Evans Schultes (Harvard University), Andrew T. Weil (University Arizona), Gerald L. Kooyman and E. E. Sinnett (Scripps 

Institution of Oceanography), Yaakov and Susanne Lipkin (Tel 

Aviv University), William Wheeler and James Woessner (UCSB), 

and Richard B. Searles (Duke University) for their gifts of algae 

collected in Sonora; David G. Lindquist (University North Carolina Wilmington; Howe, 2001) for algal specimens from El Tornillal, Rocas Consag, and Caleta Santa María; Nicolas P. Yensen 

(University Arizona) for his collection from Isla San Pedro Nolasco; Mark M. and Diane S. Littler (National Museum of Natural History [NMNH]), long-time friends, fellow marine botanists, 

divers, and “Baja-proven travelers,” for their collections of algae 

and hours of discussion; Max H. Hommersand (University North 

Carolina) and Makoto Yoshizaki (Toho University, Chiba, Japan) 

for sharing their collections and traveling with my group when we 

met them in Bahía de Los Ángeles during a trip to the east coast 

of Baja California; and Arthur E. Dennis (University Arizona) and 

Nonie McKibbin and Dale Evensen (Tucson, Arizona) for their 

collections of upper Gulf of California algae and knowledge of the 

Sonoran coast. My appreciation goes to those who made Tucson 

a home during my trips to the University of Arizona, particularly 

Craig Askin, Richard S. Felger, Ronald and Jan Pulliam (now 

University of Georgia), Robert and Ruth Hoshaw, and Alexander 

“Ike” and Jean Straub Russell. I thank Ike Russell for generously 

flying my team in his small aircraft to locales in Sonora and to Isla 

Ángel de la Guarda, enabling us to dive, collect, and work with the 

Seri, including one trip with Clinton J. Dawes (University South 

Florida) and Donald P. Cheney (Northeastern University); Ike also 

once flew to us the critical parts to get us on the road again when 

our vehicle was broken down in a remote location. I am indebted 

to Edward and Mary Beck Moser, who assisted in numerous ways, 

including sharing their home in El Desemboque (El Desemboque 

de San Ignacio; Haxöl Iihom in the Seri language) during our Sonora coast trips. I am also indebted to the Seri fishermen of El 

Desemboque and Punta Cheuca for guiding and providing boats 

for scuba diving. Their knowledge of locales, sea turtle foraging 

sites, and offshore reefs of Isla Tiburón and coastal Sonora yielded 

numerous collections, and their understanding of the sea conditions in this region kept us safe more than once. The assistance 

of Glenn and Martha Vargas (Thermal, California, and Bahía de 

Los Ángeles, Baja California) enabled my team to scuba dive on 

many of the islands in the vicinity of Bahía de Los Ángeles, and 

I thank them for their generous hospitality and numerous boat 

trips. I again extend my thanks to Donald and Isabella Abbott 

for sharing their Pacific Grove home and Hopkins Marine Station 

laboratory so Katy and I could study Gulf seaweeds; to William 

and Fran Fenical and Joan and James Stewart for letting Katy and 

me stay with them in San Diego while we were at Scripps Institution of Oceanography; to Ida and Bill Bucher and Gary and Mary 

Haden for accommodations while we were in Ventura; and to Stu 

and Linda Fredericks in Santa Barbara. 

I am grateful for the taxonomic expertise, discussions, and 

comments of Isabella A. Abbott, Luis Aguilar-Rosas, Raúl Aguilar-Rosas, Michael S. Foster, C. Fred D. Gurgel, Gayle I. Hansen, David M. Krayesky, Daniel León-Álvarez, Michael Neushul, 

Richard E. Norris, Paul C. Silva, and Michael J. Wynne. I thank 

Suzanne Fredericq, Fred Gurgel, and Paul Gabrielson for comments on the classification of the red algal orders and their 

evolutionary relationships. For advice on solving the numerous nomenclatural problems my appreciation goes to Larry J. 

Dorr (NMNH), Dan H. Nicolson (NMNH), and Robert Soreng 

(NMNH). Alex George (Murdoch University) kindly provided 

the Latin description for the new species of Gracilariopsis; Alain 

Touwaide (NMNH) checked the other new taxa and, along with 

Emanuela Appetiti (NMNH), patiently answered my queries 

on Latin and old botanical literature. I also thank Larry Dorr, 

Christopher Puttock (NMNH), and Peter Wilson (Royal Botanic Garden Sydney) for discussions on the new species names; 

Natalya “Natasha” Crump (NMHN Botany) for translation information on the publication of Perestenko (1996; in Russian); 

and Christian Feuillet (NMNH) for translating and discussion 

of publications of Me. Lemone. Francisco F. Pedroche, Luis 

Aguilar-Rosas, Raúl Aguilar-Rosas, Kathy Ann Miller (UC), and 

Rafael Riosmena-Rodríguez helped obtain important literature 

and the loan of specimens. Finally, I thank Paul M. Peterson 

(Botany Editor; NMNH) for his encouragement throughout the 

submission and review process and Contribution Series editors 

Meredith McQuoid-Greason (Smithsonian Institution Scholarly 

Press) and Tshawna Byerly for adeptly editing and preparing the 

manuscript for publication.
NUMBER 96 • 473

I thank those who have prepared or helped with illustrations: particularly Alice R. Tangerini (Botanical Illustrator, 

NMNH) for the maps, illustrations, and images of many of the 

algae—it was only with her efforts that the hundreds of figures 

were completed; and Ilka “Candy” Feller (NMNH; Smithsonian 

Environmental Research Center) and Susan Manchester (Monterey, California) for their drawings of selected algae. Most of 

the algal and habitat photographs were taken by me. Additionally, I am grateful not only for help from many others but also 

for photographs and digital images of selected herbarium specimens that were provided—most by Harvey Kupferberg (NMNH 

volunteer) and Chip Clark (NMNH Scientific Photographer) as 

well as some by Alison Habel (Photographic Illustrator, University of Arizona), Robert H. Sims (NMNH), Debbie Neuman 

Clark (NMNH), Jennifer H. Hill (NMNH Intern), and Ingrid 

Lin (NMNH Botany). For their assistance on digital photomicrography, I thank Scott Whittaker (NMNH Digital Imaging) 

and Stan Yankowski (NMNH Botany). Thanks again go to Chip 

Clark for consultation and advice on digital photography, 35mm 

photographic slide digitizing, preparation of select algal images, 

and his continued appreciation of margaritas. I am most grateful 

to Alice R. Tangerini for her skillful preparation of most of the 

digital images and line drawings and of final files of all illustrations to be published for this study. 

Again, it is impossible to express all my thanks to Katina 

Bucher Norris (NMNH Botany). Katy has participated throughout this project, in the land- and sea-based field work, scuba diving, collecting, curatorial assistance, and research collaboration 

including the study and writing the manuscript for the Ceramiales, taking the digital photomicrographs of algal images used, 

and reviewing the progressive stages of the manuscript. It is with 

Katy that I have shared many great adventures diving and traveling through the pristine desert, beaches, and reefs of Sonora and 

Baja California and the islands of the Gulf of California. To our 

sons, Shaun William and James “Jesse” Alexander, and his wife 

Alix McLearn Norris, I give thanks for their continuing interest 

in the Gulf of California, scuba diving, and marine plants and 

patiently listening to our many stories of our Baja California and 

Sonora expeditions. Finally I thank Peter G. Bernad (M.D., Alexandria, Virginia) whose patience snd extraordinary efforts made 

it possible for me to be here and finish this work.

I thank the collaborators who have contributed their expertise in the taxonomic treatments and writing of select orders, families, or genera in this treatment: Katina E. Bucher 

(Ceramiales; Nemastomatales; Tsengiaceae), Suzanne Fredericq 

(Gigartinaceae and Phyllophoraceae), C. Frederico D. Gurgel 

(Gracilariales), H. William Johansen (Corallinales), David M. 

Krayesky (Peyssonneliales and Caloglossa), and Joan G. Stewart 

(Gelidiales and Delesseriaceae). Many have been kind enough to 

review and discuss various parts of the manuscript as it developed, and I particularly thank Isabella Aiona Abbott, Robert W. 

Hoshaw, and Michael Neushul for their reviews and comments 

on the earlier drafts of the Gulf red algae. For reviewing and 

providing constructive comments on select groups of Gulf of 

California algae, I thank Isabella A. Abbott (Liagoraceae), Walter H. Adey (crustose corallines), David L. Ballantine (Champia, 

Metapeyssonnelia), Paul W. Gabrielson (Solieriaceae), Donald P. 

Cheney (Eucheuma), Gayle I. Hansen (Kallymeniaceae and 

Crossocarpaceae), Diane S. Littler and Mark M. Littler (crustose 

corallines), Richard E. Norris (Kallymenia and Pugetia), Curt M. 

Pueschel (Hildenbrandiaceae), and Michael J. Wynne (selected 

Delesseriaceae). I also extend sincere appreciation to the reviewers 

of the final draft of the manuscript—Luis Ernesto Aguilar-Rosas 

(Universidad Autónoma de Baja California, Ensenada), David L. 

Ballantine (University Puerto Rico, Mayagüez; now NMNH 

Botany), Michael S. Foster (Moss Landing Marine Laboratories 

of California State Universities), C. Frederico Gurgel (University South Australia), Juan Baptisa Lopez (University Alabama), 

Francisco F. Pedroche (Universidad Autónoma Metropolitana–

Lerma de Villada), and Rafael Riosmena-Rodríguez (Universidad 

Autónoma de Baja California Sur, La Paz)—for their reviews, 

helpful suggestions, and comments that led to its improvement. I 

deeply appreciate all the input, constructive criticism, and help, 

and I alone am responsible for any errors.

Appendix 1: 

New Names, Taxa, 

Combinations, and 

Typification

RHODOPHYTA

New Genus

Tacanoosca J. N. Norris, P. W. Gabrielson et D. P. Cheney (Solieriaceae, Gigartinales)

New Section

Neosiphonia sect. Multisiphonia, J. N. Norris (Rhodomelaceae, Ceramiales)

New Species

Chondracanthus zertuchei J. N. Norris et Fredericq (Gigartinaceae, Gigartinales)

Gracilariopsis animasensis Gurgel et J. N. Norris (Gracilariaceae, Gracilariales)

Laurencia aguilar-rosasorum J. N. Norris (Rhodomelaceae, Ceramiales)

Laurencia fenicalii J. N. Norris (Rhodomelaceae, Ceramiales)

Laurencia iriei J. N. Norris et Fenical (Rhodomelaceae, Ceramiales)

Palisada pedrochei J. N. Norris (Rhodomelaceae, Ceramiales)

Plocamium katinae J. N. Norris (Plocamiaceae, Plocamiales)

Polysiphonia hollenbergii J. N. Norris (Rhodomeaceae, Ceramiales)

New Name

Rhodymenia huertae J. N. Norris (Rhodymeniaceae, Rhodymeniales)

New Combinations

Acrochaetium seriaspora (E. Y. Dawson) J. N. Norris (Acrochaetiaceae, Acrochaetiales)

Ahnfeltiopsis hancockii (E. Y. Dawson) J. N. Norris et Fredericq (Phyllophoraceae, 

Gigartinales)
476 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Botryocladia datilensis (E. Y. Dawson) J. N. Norris (Rhodymeniaceae, Rhodymeniales)

Ceratodicyton tenuis (Setchell et N. L. Gardner) J. N. Norris

(Lomentariaceae, Rhodymeniales)

Colaconema hancockii (E. Y. Dawson) J. N. Norris (Colaconemataceae, Colaconematales)

Colaconema punctatum (E. Y. Dawson) J. N. Norris (Colaconemataceae, Colaconematales)

Colaconema scinaiae (E. Y. Dawson) J. N. Norris (Colaconemataceae, Colaconematales)

Colaconema sinicola (E. Y. Dawson) J. N. Norris (Colaconemataceae, Colaconematales)

Colaconema variabile (K. M. Drew) J. N. Norris (Colaconemataceae, Colaconematales)

Dasya pedicellata subsp. stanfordiana (Farlow) J. N. Norris et 

Bucher (Dasyaceae, Ceramiales)

Dasya pedicellata subsp. stanfordiana var. nudicaulis (E. Y. 

Dawson) J. N. Norris et Bucher (Dasyaceae, Ceramiales) 

Gloiocladia hoshawii (E. Y. Dawson) J. N. Norris (Faucheaceae, 

Rhodymeniales)

Gloiocladia mollis (M. Howe) J. N. Norris (Faucheaceae, Rhodymeniales)

Gloiocladia sefferi (M. Howe) J. N. Norris (Faucheaceae, Rhodymeniales)

Haliptilon roseum var. verticillatum (E. Y. Dawson) J. N. Norris

(Corallinaceae, Corallinales)

Mazzaella digitata (E. Y. Dawson) J. N. Norris et Fredericq (Gigartinaceae, Gigartinales)

Mazzaella diffusa (E. Y. Dawson) J. N. Norris et Fredericq (Gigartinaceae, Gigartinales)

Neosiphonia cheloniae (Hollenberg et J. N. Norris) J. N. Norris 

(Rhodomelaceae, Ceramiales)

Neosiphonia concinna (Hollenberg) J. N. Norris (Rhodomelaceae, Ceramiales)

Neosiphonia confusa (Hollenberg) J. N. Norris (Rhodomelaceae, Ceramiales)

Neosiphonia eastwoodae (Setchell et N. L. Gardner) J. N. Norris 

(Rhodomelaceae, Ceramiales)

Neosiphonia johnstonii (Setchell et N. L. Gardner) J. N. Norris 

(Rhodomelaceae, Ceramiales)

Neosiphonia masonii (Setchell et N. L. Gardner) J. N. Norris 

(Rhodomelaceae, Ceramiales)

Neosiphonia mexicana (E. Y. Dawson) J. N. Norris (Rhodomelaceae, Ceramiales)

Neosiphonia paniculata (Montagne) J. N. Norris (Rhodomelaceae, Ceramiales)

Osmundea estebaniana (Setchell et N. L. Gardner) J. N. Norris 

(Rhodomelaceae, Ceramiales)

Palisada paniculata (Kützing) J. N. Norris (Rhodomelaceae, Ceramiales)

Pterocladia sonorense (E. Y. Dawson) J. N. Norris et J. G. 

Stewart (Pterocladiaceae, Gelidiales)

Tacanoosca uncinata (Setchell et N. L. Gardner) J. N. Norris,

P. W. Gabrielson et D. P. Cheney (Solieriaceae, Gigartinales)

Tsengia abbottiana (J. N. Norris et Bucher) J. N. Norris et 

Bucher (Tsengiaceae, Cryptonemiales)

Typification: Lectotype

Laurencia paniculata Kützing (Rhodomelaceae, Ceramiales)
Appendix 2: 

Endemic Rhodophyta of 

the Gulf of California that 

Occur in the Northern Gulf

Bangiales: Bangiaceae

Pyropia hollenbergii 

Pyropia pendula

Acrochaetiales: Acrochaetiaceae

Acrochaetium seriaspora

Colaconematales: Colaconemataceae

Colaconema hancockii

Colaconema punctatum

Nemaliales: Liagoraceae

Liagora magniinvolucra

Corallinales: Corallinaceae

Heteroderma corallinicola

Heteroderma gibbsii

Lithophyllum diguetii

Lithophyllum margaritae

Ceramiales: Callithamniaceae

Callithamnion bisporum var. australe
478 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Ceramiales: Ceramiaceae

Ceramium obesum

Ceramium periconicum

Ceramium sinicola var. johnstonii

Gayliella species A

Pterothamnion tepocense

Ceramiales: Dasyaceae

Dasya pedicellata subsp. stanfordiana var. nudicaulis

Ceramiales: Delesseriaceae

Myriogramme auricularis

Myriogramme divaricata 

Phycodrys amplissima

Phycodrys lucasana

Phycodrys simplex

Polyneurella hancockii var. rhizoidea 

Ceramiales: Rhodomelaceae

Chondria species A

Laurencia aguilar-rosasorum 

Laurencia fenicalii

Laurencia iriei

Neosiphonia cheloniae 

Osmundea estebaniana

Polysiphonia hollenbergii

Polysiphonia sonorensis

Ceramiales: Wrangeliaceae

Lejolisia hoshawii

Gelidiales: Gelidiaceae

Gelidium decompositum

Gelidium refugiensis

Pterocladia sonorense

Gigartinales: Gigartinaceae

Chondracanthus squarrulosus

Chondracanthus zertuchei

Mazzaella diffusa

Mazzaella digitata

Gigartinales: Kallymeniaceae

Kallymenia baldwini

Kallymenia bleckii 

Kallymenia pertusa 

Gigartinales: Phyllophoraceae

Gymnogongrus? carnosus

Gigartinales: Solieriaceae

Agardhiella mexicana

Sarcodiotheca dichotoma 

Sarcodiotheca taylorii

Gracilariales: Gracilariaceae

Gracilaria ascidiicola

Gracilaria marcialana

Gracilaria pinnata

Gracilaria rubrimembra

Gracilaria spinigera

Gracilaria subsecundata

Gracilaria tepocensis

Gracilaria vivesii

Cryptonemiales: Halymeniaceae

Cryptonemia opuntioides

Cryptonemia veleroae

Grateloupia dactylifera

Grateloupia violacea

Halymenia bifida

Halymenia megaspora

Prionitis abbreviata var. guaymasensis

Nemastomatales: Schizymeniaceae

Platoma? fanii

Plocamiales: Plocamiaceae

Plocamium katinae

Rhodymeniales: Champiaceae

Champia disticha 

Rhodymeniales: Faucheaceae

Gloiocladia hoshawii 

Gloiocladia mollis 

Gloiocladia sefferi

Gloioderma conjuncta

Rhodymeniales: Rhodymeniaceae

Botryocladia datilensis

Botryocladia guaymasensis

Rhodymenia huertae
Appendix 3: 

Rhodophyta Specimens 

Illustrated: Species Locality 

Information and Herbarium

Stylonema alsidii (Figure 9A): Epiphytic on Cladophora, subtidal, Islas de Los Gemelos, 

Bahía de Los Ángeles, Baja California, Coll. H. Sleeper and M. Helvey (JN-4491b; 

US Alg. Coll. microscope slide 4268).

Stylonema cornu-cervi (Figure 9B): Epiphytic on Anotrichium secundum, rock reef, 1.5–

4.6 m depths, off the west side of sand-cobble beach, Punta Robinson (~2.4 km east 

of Puerto Libertad), Sonora, Coll. J. N. Norris and K. E. Bucher (JN-4836; US Alg. 

Coll. microscope slide 4974).

Erythrocladia irregularis (Figure 10A): Epizoic on Sertularia, 9.1–18.3 m depths, Peavine 

Pass (between Obstruction Island and Barkley Island), and Shaw Island, San Juan 

Islands, Washington, Coll. H. Kylin (LD).

Sahlingia subintegra (Figure 10B): Epizoic on Sertularia, 9.1–18.3 m depths, Peavine 

Pass (between Obstruction Island and Barkley Island), and Shaw Island, San Juan 

Islands, Washington, Coll. H. Kylin (LD).

Erythrotrichia biseriata (Figure 11): Epiphytic on Halymenia californica (JN-3202a), 

Estero de Bahía de Las Ánimas, Baja California, Coll. J. N. Norris (JN-3203c, US 

Alg. Coll. microscope slide 4251).

Erythrotrichia biseriata (Figure 12A–C): Hatidyō Island, Japan (Type: BLIH 1829c, Herbarium of the Biological Laboratory, Imperial Palace, Tokyo).

Erythrotrichia carnea f. tenuis (Figure 12D, E): Type locality uncertain, several syntype 

localities listed by Tanaka (1944).

Erythrotrichia parksii var. minor (Figure 13): Epiphytic on Colpomenia tuberculata, 9 

m depth, rocky point, SE side of Punta Pelícano, vicinity of Puerto Peñasco, Sonora, 
480 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Coll. J. N. Norris, K. E. Bucher, and D. Moore (JN-5037, 

US Alg. Coll. microscope slide 4276).

Erythrotrichia tetraseriata (Figure 14): Epiphytic on Chondria 

decipiens, Municipal Wharf, Monterey, California, Coll. 

H. Kylin (type of Erythrotrichia californica Kylin: LD).

Porphyrostromium boryanum (Figure 15A, B): On Gelidium 

corneum, Fort des Anglais, Algeria, Coll. J. B. G. M. Bory 

de Saint-Vincent (type of Porphyra boryana Montagne, 

1846b, Montagne Herbarium in PC; after Ardré, 1970: pl. 

4: figs. 10, 11).

Porphyrostromium ciliare (Figure 15C): Punta Baja, Pacific 

Baja California, Coll. E. Y. Dawson (EYD-1255, AHFH, 

now UC).

Bangia enteromorphoides (Figure 16): 2.4–6 m depths, entangled with Asparagopsis, Punta la Gringa, Bahía de Los 

Ángeles, Baja California, Coll. J. N. Norris and G. Boehlert 

(JN-3030b, US Alg. Coll. microscope slide 8696).

Bangia vermicularis? (Figure 17): Pebble Beach, Monterey, California (GMS).

Pyropia thuretii (Figure 18A): Intertidal, Punta Diggs, south of 

San Felipe, Baja California, Coll. L. Carpelan (EYD-12546, 

US Alg. Coll.-41997).

Pyropia pendula (Figure 18B): Northeast side of cove, Isla San 

Pedro Nolasco, Coll. N. P. Yensen (JN-5194a, US Alg. Coll.-

160625). 

Pyropia thuretii (Figure 18C, D): Northeast side of cove, Isla 

San Pedro Nolasco, Coll. N. P. Yensen (JN-5194b: C, 

US Alg. Coll.-160627; D, US Alg. Coll. microscope slide 

4297).

Conchocelis-phase (Figure 19): Laboratory cultures of filaments 

of Conchocelis developed from carpospores of Pyropia perforata that were collected from intertidal rocks, Hopkins 

Marine Station of Stanford University, Pacific Grove, California, Coll. G. J. Hollenberg 

Hildenbrandia prototypus (Figure 20): Outer, seaward shore 

of San Quintin Peninsula (opposite Isla San Martín), Baja 

California, Pacific Mexico, Coll. E. Y. Dawson (EYD- 8730, 

AHFH, now UC).

Acrochaetium secundatum (Figure 21F): Bahía Bocochibampo, 

Sonora, Coll. E. Y. Dawson (EYD-462a, AHFH, now UC).

Acrochaetium seriaspora (Figure 21G–J): Isla Turner, Coll. E. Y. 

Dawson (EYD-736-40, AHFH, now UC).

Acrochaetium crassipes (Figure 22): Epiphytic on Cladophora, 

intertidal rock platform, Playa Hermosa, vicinity of Puerto 

Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN4040b, US Alg. Coll. microscope slide 4254).

Colaconema hancockii (Figure 23A, B): Epiphytic on Gelidium, 

Puerto Refugio, Isla Ángel de la Guarda, Coll. E. Y. Dawson 

(EYD-218a, type collection, AHFH, now UC).

Colaconema punctatum (Figure 23G): Bahía Bocochibampo, 

Sonora (EYD-462b type collection, AHFH, now UC).

Colaconema sinicola (Figure 23J): Epiphytic on Dictyota, Isla 

Turner, Coll. E. Y. Dawson (EYD-739, type collection, 

AHFH-17, now UC).

Dichotomaria marginata (Figure 24A): On rocks, 4.6–9.0 m 

depths, Caleta Santa María (north of Santa Rosalía), Baja 

California Sur, Coll. D. G. Lindquist (JN-3400a, US Alg. 

Coll.-159143).

Dichotomaria marginata (Figure 24B, C): Off west side of small 

cove, 6 m depth, Punta Cirio (south of Puerto Libertad), 

Sonora, Coll. J. N. Norris, K. E. Bucher, and D. Moore (JN4891a, US Alg. Coll. microscope slide 8707).

Dichotomaria spathulata (Figure 25A): Intertidal, Playa Las 

Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. 

J. N. Norris and K. E. Bucher (JN-5859, US Alg. Coll.-

159150).

Dichotomaria spathulata (Figure 25B): Off west side of small 

cove, 6 m depth, Punta Cirio (south of Puerto Libertad), 

Sonora, Coll. J. N. Norris, K. E. Bucher, and D. Moore (JN4891b, US Alg. Coll. microscope slide 8708). 

Dichotomaria spathulata (Figure 25C): Intertidal rocks 

fronting Laboratorio de Biología Marina, Playa Las 

Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. 

J. N. Norris (JN-2941, US Alg. Coll. microscope slide 

5366).

Galaxaura ramulosa (Figure 26A): Rocky intertidal and tide 

pools, Playa Las Conchas (Playa Estación), Puerto Peñasco, 

Sonora, Coll. J. N. Norris and K. E. Bucher (JN-3563, US 

Alg. Coll.-159169). 

Galaxaura ramulosa (Figure 26B): Rocky intertidal fronting 

Laboratorio de Biología Marina, Playa Las Conchas (Playa 

Estación), Puerto Peñasco, Sonora, Coll. A. E. Dennis 

(EYD-27457, US Alg. Coll.-40824). 

Galaxaura ramulosa (Figure 26C): Low intertidal rocks in front 

of Casa Garcia, Playa Las Conchas (Playa Estación), Puerto 

Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN3080, US Alg. Coll.-159167: liquid material in US Alg. Coll. 

jar 560, vial 5720). 

Galaxaura ramulosa (Figure 26D, E): 1.5–6.1 m depths, Nueva 

Guaymas (Bahía de San Carlos), Sonora, Coll. D. Evanson 

(JN-4280, US Alg. Coll. microscope slide 8697).

Galaxaura rugosa (Figure 27A): Intertidal rock platform, Playa 

Las Conchas (Playa Estación), Puerto Peñasco, Sonora, 

Coll. J. N. Norris and K. E. Bucher (JN-3634, US Alg. Coll.-

159199). 

Galaxaura rugosa (Figure 27B–D): Low intertidal rocks in front 

of Casa Garcia, Playa Las Conchas (Playa Estación), Puerto 
NUMBER 96 • 481

Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN3077, US Alg. Coll. microscope slide 8698).

Tricleocarpa cylindrica (Figure 28A): Rocky intertidal, Cabo 

Tepoca (SE of Puerto Lobos), Sonora, Coll. J. N. Norris 

(JN-5955, US Alg. Coll.-159165).

Tricleocarpa cylindrica (Figure 28B): Intertidal rocks in front 

of Casa Garcia, Playa Las Conchas (Playa Estación), Puerto 

Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN3078, US Alg. Coll. microscope slide 8699).

Ganonema farinosum (Figure 29A): 1.8 m depth, near the reef 

off south end of Isla San Diego, Coll. E. Y. Dawson (EYD18914, US Alg. Coll.-8101). 

Ganonema farinosum (Figure 29B): Shallow subtidal, Los Frailes, 

Baja California Sur, Coll. Valerie Paul (JN-7173, US Alg. 

Coll.-160431).

Liagora ceranoides (Figure 30): Drift cast ashore, Playa Las 

Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. 

J. N. Norris (JN-3195, US Alg. Coll.-160430).

Liagora magniinvolucra (Figure 31A): In tide pool, Playa 

Arenosa, vicinity of Puerto Peñasco, Sonora, Coll. R. D. 

Staker, s.n. (US Alg. Coll.-204280). 

Liagora magniinvolucra (Figure 31B, C): On side of rock in 

Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher 

(JN-4046, US Alg. Coll. microscope slide 4283).

Scinaia confusa (Figure 32A): Intertidal to 9 m depth, NW of 

the rock window on shore, Puerto Refugio, Isla Ángel de la 

Guarda, Coll. J. N. Norris and K. E. Bucher (JN-5302, US 

Alg. Coll.-217350).

Scinaia confusa (Figure 32B, C): 9 m depth, on rocks, off rocky 

point, SE side of Punta Pelícano, vicinity of Puerto Peñasco, 

Sonora, Coll. J. N. Norris, K. E. Bucher, and D. Moore (JN5024, US Alg. Coll. microscope slide 4247).

Scinaia johnstoniae (Figure 33A, B): 15–22 m depths, dive off 

east end of Isla Mejia, Isla Ángel de la Guarda, Coll. J. N. 

Norris, J. Paul, and K. Robertson (JN-5670: A, US Alg. 

Coll.-217351; B, US Alg. Coll.-160916). 

Scinaia johnstoniae (Figure 33C): Dive to 9 m depth, on rocks, 

off rocky point, SE side of Punta Pelícano, vicinity of Puerto 

Peñasco, Sonora, Coll. J. N. Norris, K. E. Bucher, and 

D. Moore (JN-5023, US Alg. Coll.-160907).

Scinaia johnstoniae (Figure 34): 9 m depth, on rocks, off rocky 

point, SE side of Punta Pelícano, vicinity of Puerto Peñasco, 

Sonora, Coll. J. N. Norris, K. E. Bucher, and D. Moore (JN5023, US Alg. Coll. microscope slide 4301).

Scinaia latifrons (Figure 35): 9 m depth, on rocks, off rocky 

point, SE side of Punta Peícano, vicinity of Puerto Peñasco, 

Sonora, Coll. J. N. Norris, K. E. Bucher, and D. Moore (JN5049, US Alg. Coll.-160925).

Corallina officinalis var. chilensis (Figure 36A): Rocky shore, 

low intertidal, Cabo Colnett, Baja California, Pacific Mexico (EYD-53, AHFH, now UC).

Corallina vancouveriensis (Figure 36B): Small reef and boulder 

beach, Rio San Telmo, Baja California, Pacific Mexico, Coll. 

D. Fork (EYD-147, AHFH, now UC).

Corallina pinnatifolia var. pinnatifolia (Figure 37A): Intertidal 

rocks east of the village, San Felipe, Baja California, Coll. 

E. Y. Dawson, H. B. S. Womersley, and M. S. Doty (EYD10673, US Alg. Coll.-6998).

Corallina polysticha (Figure 37B): Intertidal rocky shore, ~4.0 

km north of South Bluff, Isla Guadalupe, Baja California, 

Pacific Mexico (holotype: EYD-8355, AHFH, now UC).

Corallina pinnatifolia var. digitata (Figure 37C, D): On tidal 

platform, Playa Las Conchas (Playa Estación), Puerto 

Peñasco, Sonora, Coll. J. N. Norris (JN-3687, US Alg. Coll.). 

Corallina pinnatifolia var. digitata (Figure 37E): On rocks, Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher 

(JN-4593, US Alg. Coll.).

Jania adhaerens (Figure 38A): Epiphytic on Sargassum, mid to 

low intertidal, tidal platform, Playa Las Conchas (Playa 

Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and 

K. E. Bucher (JN-3632b, US Alg. Coll.). 

Jania adhaerens (Figure 38B): Some on Sargassum stipes, Playa 

Arenosa (Sandy Beach and Norse Beach), Puerto Peñasco, 

Sonora, Coll. H. W. Johansen, E. Johansen, and J. N. Norris 

(JN & HWJ-73-7-12, US Alg. Coll.).

Jania adhaerens (Figure 39A): Intertidal, Cumpleaños Tide 

Pool, Playa Las Conchas (Playa Estación), Puerto Peñasco, 

Sonora, Coll. J. N. Norris and K. E. Bucher (JN-3529, US 

Alg. Coll.).

Jania longiarthra (Figure 39C): Near the reef, along south end 

of island, Isla San Diego, Baja California Sur (EYD-18920, 

US Alg. Coll.-8022).

Jania longiarthra (Figure 39E): Among turf algae, in inner Bahía 

San Gabriél, Isla Espíritu Santo, Baja California Sur, Coll. 

E. Y. Dawson (holotype: EYD-7041, AHFH, now UC).

Jania mexicana (Figure 39F): Bahía Petatlán, Guerrero, Pacific 

Mexico (isotype: WRTaylor -34-569, MICH).

Jania huertae (Figure 40): Among intertidal turf algae, Bahía 

Kino, southeast of Isla Pelícanos, Sonora, Coll. Oscar Olguin Q., s.n. (holotype: ENCB).

Amphiroa beauvoisii (Figure 41): Intertidal, on rocks, Punta 

Pelícano, vicinity of Puerto Peñasco, Sonora, Coll. J. N. 

Norris, H. W. Johansen, E. Johansen, and K. E. Bucher (JN 

& HWJ-73-7-3, US Alg. Coll.).
482 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Amphiroa misakiensis (Figure 42A): Mid intertidal, on rocks of 

tidal platform and Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. 

Norris and K. E. Bucher (JN-3674, US Alg. Coll.). 

Amphiroa misakiensis (Figure 42B): Mid intertidal on rocks of 

tidal platform, Playa Las Conchas (Playa Estación), Puerto 

Peñasco, Sonora, Coll. J. N. Norris (JN-3684, US Alg. Coll.).

Amphiroa misakiensis (Figure 42C): Mid intertidal rock platform and tide pools, Playa Las Conchas (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher 

(JN-5102, US Alg. Coll.).

Amphiroa valonioides (Figure 43A): Mid intertidal, on tidal 

platform, west of Casa Garcia, Playa Las Conchas (Playa 

Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and 

K. E. Bucher (JN-3146b, US Alg. Coll.). 

Amphiroa valonioides (Figure 43B): On rocks, Punta Pelícano, 

vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris, H. W. 

Johansen, E. Johansen, and K. E. Bucher (JN & HWJ-73-7-

4, US Alg. Coll.).

Amphiroa valonioides (Figure 43C): Cumpleaños Tide Pool, 

Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. H. W. Johansen, E. Johansen, and J. N. Norris 

(JN & HWJ-73-7-33, US Alg. Coll.).

Amphiroa vanbosseae (Figure 44A): Rocky shore, Punta Colorado, near Guaymas, Sonora, Coll. E. Y. Dawson (type of 

Amphiroa subcylindrica: EYD-555, AHFH-4277, now UC).

Amphiroa vanbosseae (Figure 44B): On low intertidal rocks, 

Punta Pelícano, vicinity of Puerto Peñasco, Sonora, Coll. 

J. N. Norris, H. W. Johansen, E. Johansen, and K. E. Bucher 

(JN & HWJ-73-7-1, US Alg. Coll.).

Amphiroa vanbosseae (Figure 44C): 2.4–6 m depths, Punta la 

Gringa, Bahía de los Ángeles, Baja California, Coll. J. N. 

Norris and G. Boehlert (JN-3050, US Alg. Coll.).

Litholepis sonorensis (Figure 45A): Canal de San Lorenzo, between southern end of Isla Espíritu Santo and Punta San Lorenzo on east coast of Baja California (NE of La Paz), Baja 

California Sur, Coll. E. Y. Dawson (holotype: EYD-592-40, 

AHFH, now UC).

Heteroderma corallinicola (Figure 45B): On Corallina in intertidal pools in the cove north of Cabo Arco, Guaymas, Sonora 

(holotype: Drouet & Richards-3328a, AHFH, now UC).

Lithophyllum diguetii (Figure 46): Dredged, Canal de San Lorenzo, channel between southern end of Isla Espíritu Santo 

and Punta San Lorenzo on east coast of Baja California 

(northeast of La Paz), Baja California Sur, Coll. E. Y. Dawson (A, C–G, EYD-591-40, AHFH, now UC; B, isotype: 

L. Diguet-1894, UC).

Lithophyllum hancockii (Figure 47): Shallow lagoon, Bahía San 

Gabriel, Isla Espíritu Santo, Baja California Sur, Coll. E. Y. 

Dawson (holotype EYD-619a-40, AHFH-22, now UC).

Lithophyllum imitans (Figure 48A): On rocks, Punta Pelícano, 

vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris, H. W. 

Johansen, E. Johansen, and K. E. Bucher (JN & HWJ-73-7-

11a, US Alg. Coll.).

Lithophyllum imitans (Figure 48B): Intertidal rock platform, 

Playa Hermosa (~0.8 km west of Playa Hermosa Hotel), 

vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris and 

K. E. Bucher (JN-4025, US Alg. Coll.).

Lithophyllum margaritae (Figure 48C): Canal de San Lorenzo 

(channel between the southern end of Isla Espíritu Santo 

and northern peninsula from Punta Coyote to Punta San 

Lorenzo, near entrance to Báhia de La Paz), Baja California 

Sur, coll. E. Y. Dawson (EYD-6942, AHFH, now UC).

Lithophyllum pallescens (Figure 49A): Dredged 12–22 m depths, 

on sand–rhodolith bottom, Canal de Mejia (between southern end of Isla Mejia and northern end of Puerto Refugio, 

Isla Ángel de la Guarda, Coll. E. Y. Dawson (EYD-278-40, 

AHFH, now UC).

Lithophyllum pallescens (Figure 49B): Dredged 38.4 m depth, on 

shell bottom, west side of Puerto Refugio, Isla Ángel de la 

Guarda, Coll. E. Y. Dawson (EYD-250-40, AHFH, now UC).

Lithophyllum pallescens (Figure 49C): On hermit crab shell, 

Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher

(JN-3586, US Alg. Coll.). 

Lithophyllum pallescens (Figure 49D): On sand bottom with 

some coralline clumps, shallow lagoon, 1.5–2.4 m depths, 

Bahía San Gabriel, Isla Espíritu Santo, Baja California Sur, 

Coll. E. Y. Dawson (EYD-572-40, AHFH, now UC).

Lithophyllum pallescens (Figure 49E): In tide pool, Playa Hermosa, vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris 

and K. E. Bucher (JN-3503, US Alg. Coll.).

Lithophyllum proboscideum (Figure 50A): Growing on intertidal rocks, Punta Pelícano, vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris (JN-3825, US Alg. Coll.). 

Lithophyllum proboscideum (Figure 50B): Intertidal rock platform and tide pools, Playa Hermosa (~0.8 km west of Playa 

Hermosa Hotel), vicinity of Puerto Peñasco, Sonora, Coll. 

J. N. Norris and K. E. Bucher (JN-3471, US Alg. Coll.).

Titanoderma dispar (Figure 51): Irregularly shaped crusts epiphytic on Gelidium, some completely surrounding host 

branches, intertidal rocks in front of Japanese shipwreck, 

Cabeza Ballena, Coll. J. N. Norris and K. E. Bucher (JN4112, US Alg. Coll.).

Hydrolithon farinosum (Figure 52): Intertidal, epiphytic on Padina, tidal platform, Playa Las Conchas (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher 

(JN-3169, US Alg. Coll.).

Heteroderma gibbsii (Figure 53): Epiphytic on Padina, on 

“rough” cobbles, intertidal rocky shore south side of bay, 
NUMBER 96 • 483

Ensenada Bocochibampo, Sonora, Coll. E. Y. Dawson

(EYD-457, AHFH, now UC).

Heteroderma gibbsii (Figure 54A): Epiphytic on Padina,

Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. H. W. Johansen, E. 

Johansen, and J. N. Norris (JN & HWJ-73-7-22c, US Alg. 

Coll.). 

Heteroderma gibbsii (Figure 54B): Thin crusts epiphytic on Padina, Playa Arenosa (Sandy Beach, Norse Beach), vicinity of 

Puerto Peñasco, Sonora, Coll. H. W. Johansen, E. Johansen, 

and J. N. Norris (JN & HWJ-73-7-15, US Alg. Coll.).

Heteroderma subtilissimum (Figure 55): On Cladophoropsis, 

south end of Isla Guadalupe, Pacific Mexico (EYD-8191, 

AHFH, now UC).

Spongites decipiens (Figure 56A): Intertidal, Punta Prieta, outer 

Bahía Topolobampo, Sinaloa, Coll. E. Y. Dawson (EYD10967, AHFH, now UC). 

Spongites decipiens (Figure 56B): High intertidal in tide pool, 

growing on small rocks, Punta Pelícano, vicinity of Puerto 

Peñasco, Sonora, Coll. J. N. Norris and R. W. Hoshaw (JN3829, US Alg. Coll.).

Spongites decipiens (Figure 56C): Intertidal platform, Playa 

Arenosa (Norse Beach; Sandy Beach), Coll. J. N. Norris, 

Y. Lipkin, and S. Lipkin (JN-3932, US Alg. Coll.).

Spongites decipiens (Figure 56D): Intertidal rock platform and 

tide pools, Playa Hermosa (~0.8 km west of Playa Hermosa 

Hotel), vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN-3504).

Neogoniolithon trichotomum (Figure 57A): Vicinity of La Paz, 

Baja California Sur (isotype: L. Diguet-1894, UC). 

Neogoniolithon trichotomum (Figure 57B): Bahía San Gabriel, 

Isla Espíritu Santo, Baja California Sur, Coll. E. Y. Dawson 

(EYD-619-40, AHFH, now UC). 

Neogoniolithon trichotomum (Figure 57C): Reef and tidal flat, 

near entrance to Bahía San Carlos, north side of Ensenada 

de San Francisco, vicinity of Guaymas, Sonora, Coll. E. Y. 

Dawson (EYD-1972, AHFH, now UC). 

Neogoniolithon trichotomum (Figure 57D): Rocky shore and 

tidal benches, west side of Puerto Refugio, Isla Ángel de 

la Guarda, Coll. E. Y. Dawson (EYD-226-40, AHFH, 

now UC).

Porolithon sonorense (Figure 58A, B): Rocky shore and tidal 

benches, west side of Puerto Refugio, Isla Ángel de la Guarda 

(type collection, EYD-226a-40, AHFH-25, now UC).

Porolithon sonorense (Figure 58C): Intertidal on rock, Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris and M. M. Littler (JN-3775, US Alg. Coll.).

Porolithon sonorense (Figure 58D): Isla Partida, near Isla Espíritu Santo, Baja California (EYD-984, AHFH now UC).

Lithothamnion australe (Figure 59A): Dredged in 3.6–5.5 m 

depths, Bahía Guaymas, Sonora, Coll. E. Y. Dawson (EYD61-40, AHFH, now UC).

Lithothamnion australe (Figure 59B, C): Dredged in 10–24 m 

depths, Canal de San Lorenzo, between Punta San Lorenzo 

on Gulf coast of Baja California and southern end of Isla Espíritu Santo, Baja California Sur, Coll. E. Y. Dawson (EYD593a, AHFH, now UC).

Lithothamnion microsporum (Figure 60A): Rock sides and 

ledges, Cumpleaños Tide Pool, Playa Las Conchas (Playa 

Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and 

K. E. Bucher (JN-3532, US Alg. Coll.). 

Lithothamnion microsporum (Figure 60B): Playa Tucson, north 

side of Punta Pelícano, vicinity of Puerto Peñasco, Sonora, 

Coll. J. N. Norris and K. E. Bucher (JN-3462, US Alg. Coll.).

Mesophyllum crassiusculum (Figure 61A): Dredging 12–14.6 m, 

South Coronado Island, Islas Coronado, Baja California, 

Pacific Mexico, Coll. E. Y. Dawson (EYD-4277, AHFH, 

now UC). 

Mesophyllum crassiusculum (Figure 61B, C): Isla Concha, Laguna de Ojo de Liebra (Scammon’s Lagoon), Baja California Sur, Pacific Mexico, Coll. K. Kenyon and W. Williams 

(EYD-2636, AHFH, now UC).

Ahnfeltia svensonii (Figure 62): Isla Cholla, off north end of Isla 

Carmen, Baja California Sur, Coll. E. Y. Dawson (cruise of 

M/V Stella Polaris) (EYD-18747, US Alg. Coll.-6444).

Asparagopsis taxiformis (Figure 63A): 7.6,–9 m depths, attached to rocks, west side of large rock, Rocas Consag, 

upper Gulf of California, Coll. D. G. Lindquist (JN-3113, 

US Alg. Coll.-158607). 

Asparagopsis taxiformis (Figure 63B): Rock reef, off sandcobble beach, 1.5–4.6 m depths, west side of Punta Robinson, ~2.4 km east of Puerto Libertad, Sonora, Coll. J. N. 

Norris and K. E. Bucher (JN-4822, US Alg. Coll. microscope slide 4975).

Falkenbergia hillebrandii-phase of Asparagopsis (Figure 64A):

7.6–18 m depths, rocky substrate, Isla la Ventana, Bahía de 

Los Ángeles, Baja California, Coll. J. N. Norris, M. Helvey, 

and H. Sleeper (JN-4438, US Alg. Coll. microscope slide 

4292). 

Falkenbergia hillebrandii-phase of Asparagopsis (Figure 64B, 

C): Dive to 10.6–30 m depths, Islas de Los Gemelos, Bahía 

de Los Ángeles, Baja California, Coll. J. N. Norris, H. Sleeper, and W. Baines (JN-4758, US Alg. Coll. microscope slide 

4295).

Bonnemaisonia hamifera (Figure 65A, C): 1–7.6 m depths, 

Punta la Gringa, Bahía de los Ángeles, Baja California, 

Coll. J. N. Norris and K. E. Bucher (JN-5438, US Alg. 

Coll.-158653). 
484 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Bonnemaisonia hamifera (Figure 65B, D): 15 m depth, Isla la 

Ventana, Bahía de Los Ángeles, Baja California, Coll. J. N. 

Norris and G. Boehlert (JN-2989, US Alg. Coll. microscope 

slide 4277).

Callithamnion bisporum var. australe (Figure 66): Dredged 

5.5–9 m depths, Puerto Escondido, Baja California Sur, 

Coll. E. Y. Dawson (isotype: EYD-7190, US Alg. Coll. 

microscope slide 333).

Crouania attenuata (Figure 67): Epiphytic on Amphiroa, near 

rock reef, 1.5–4.6 m depths, west side of Punta Robinson, 

~2.4 km east of Puerto Libertad, Sonora, Coll. J. N. Norris 

and K. E. Bucher (JN-4842, US Alg. Coll. microscope slide 

4705).

Crouanophycus mcnabbii (Figure 68): Epiphytic on Dictyota 

crenulata, 4.6–9 m depths, Caleta Santa María Cove, 9.7 

km north of Puerto Santa Rosalía, Baja California Sur, Coll. 

D. G. Lindquist (sta. DGL 720811-1) (JN-3406, US Alg. 

Coll. microscope slide 4717).

Antithamnion decipiens (Figure 69A): Epiphytic on Sargassum

stipe, dive to 6 m depth off west side of small cove, Punta 

Cirio, south of Puerto Libertad, Sonora, Coll. J. N. Norris, 

K. E. Bucher, and D. Moore (JN-4921, US Alg. Coll. microscope slide 4750).

Antithamnion decipiens (Figure 69B): Epiphytic on Dictyopteris, dive 1.5–4.6 m depths, ~0.8 km south of shipwreck, 

Cabeza Ballena, Baja California Sur, Coll. J. N. Norris (JN4146, US Alg. Coll. microscope slide 4719).

Antithamnion defectum (Figure 70A): Dive 10.6–30 m depths, 

Islas de Los Gemelos, Bahía de Los Ángeles, Baja California, 

Coll. J. N. Norris, H. Sleeper, and W. Baines (JN-4758b, 

entangled with Falkenbergia-stage of Asparagopsis, US Alg. 

Coll. microscope slide 4295).

Antithamnion defectum (Figure 70B): Dive 10.6–30 m depths, 

Islas de Los Gemelos, Bahía de los Ángeles, Baja California, 

Coll. J. N. Norris, H. Sleeper, and W. Baines (JN-4757, US 

Alg. Coll. microscope slide 4731).

Antithamnion kylinii (Figure 71A, B, D): On carapace of female Chelonia (black sea turtle), 9 m depth, vicinity of 

Campo Ona, Canal de Infiernillo, Sonora, Coll. R. S. Felger, 

E. Moser, Guadalupe Méndez (harpooned turtle, Seri) (JN4780: A, US Alg. Coll. microscope slide 4741; B, US Alg. 

Coll. microscope slide 4736; D, US Alg. Coll. microscope 

slide 4735). 

Antithamnion kylinii (Figure 71C): 13.7 m depth, attached to 

sea shells on muddy bottom, Canal de Infiernillo, midway 

between Isla Tiburón and west of Campo Viboras, Sonora, 

Coll. G. L. Kooyman and E. Sinnett (JN-4735, US Alg. Coll. 

microscope slide 4729).

Antithamnionella breviramosa (Figure 72A): Epiphytic on 

Gelidium, dive 7.6–18 m depths, Isla la Ventana, Bahía de 

Los Ángeles, Baja California, Coll. J. N. Norris, M. Helvey, 

and H. Sleeper (JN-4435, US Alg. Coll. microscope slide 

4727). 

Antithamnionella breviramosa (Figure 72B): Epiphytic on Lomentaria, dive to 6 m depth, off small cove, Punta Cirio, 

south of Puerto Libertad, Sonora, Coll. J. N. Norris, K. E. 

Bucher, and D. Moore (JN-4908, US Alg. Coll. microscope 

slide 4751).

Antithamnionella breviramosa (Figure 72C): Dive to 9 m depth, 

rocky point inside SE side of Punta Pelícano, vicinity of 

Puerto Peñasco, Sonora, Coll. J. N. Norris, K. E. Bucher, 

and D. Moore (JN-5064b, US Alg. Coll. microscope slide 

4840). 

Antithamnionella breviramosa (Figure 72D, E): Epizoic on a 

bryozoan, rocky point inside SE side of Punta Pelícano, vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris, K. E. 

Bucher, and D. Moore (JN-5042, US Alg. Coll. microscope 

slide 4757). 

Antithamnionella breviramosa (Figure 72F): Hand dredge 9.1–

22.8 m, Isla Las Ánimas (Isla San Lorenzo del Norte), Islas 

de San Lorenzo, Coll. E. Y. Dawson, R. Banks, E. Wilson, 

and J. Sloan (California Department of Fish and Game; M/V 

Alaska expedition) (EYD-26126, US Alg. Coll. microscope 

slide 788).

Antithamnionella cf. spirographidis (Figure 73): On carapace 

of female Chelonia (black sea turtle), 9 m depth, vicinity of 

Campo Ona, Canal de Infiernillo, Sonora, Coll. R. S. Felger, 

E. Moser, and Guadalupe Méndez (Seri) (JN-4769, US Alg. 

Coll. microscope slide 4734).

Centroceras gasparrinii (Figure 74A): 1.5–6 m depths, Nueva 

Guaymas, Bahía de San Carlos, Sonora, Coll. D. Evanson 

(JN-4285, US Alg. Coll. microscope slide 4792). 

Centroceras gasparrinii (Figure 74B–D): Dive 1.5–4.6 m depths, 

~0.8 km south of shipwreck, Cabeza Ballena, Baja California Sur, Coll. J. N. Norris and K. E. Bucher (B, JN-4131a, 

US Alg. Coll. microscope slide 4784; C, JN-4131b, US Alg. 

Coll. microscope slide 8700; D, JN-4131e, US Alg. Coll. 

microscope slide 4759).

Ceramium aduncum (Figure 75A): Dive to 9 m depth, off rocky 

point, inside of SE side of Punta Pelícano, vicinity of Puerto 

Peñasco, Sonora, Coll. J. N. Norris, K. E. Bucher, and 

D. Moore (JN-5060, US Alg. Coll. microscope slide 8701). 

Ceramium aduncum (Figure 75B): Rocky intertidal, Punta Pelícano, vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris 

and K. E. Bucher (JN-3098, US Alg. Coll. microscope slide 

8690).

Ceramium affine var. peninsularis (Figure 76): Intertidal rocky 

platform, Playa Hermosa (~0.8 km west of Playa Hermosa 
NUMBER 96 • 485

Hotel), Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. 

Bucher (JN-4002, US Alg. Coll. microscope slide 8702).

Ceramium caudatum (Figure 77A): Epiphytic on Padina, dive 

to 6 m depth, off small cove, Punta Cirio, south of Puerto 

Libertad, Sonora, Coll. J. N. Norris, K. E. Bucher, and 

D. Moore (JN-4904b, US Alg. Coll. microscope slide 5256). 

Ceramium caudatum (Figure 77B): Epiphytic on Prionitis, dive 

3–15 m depths, off north end of island, Isla Coronado, 

Bahía de Los Ángeles, Baja California, Coll. H. Sleeper and 

M. Helvey (JN-4400, US Alg. Coll. microscope slide 8709). 

Ceramium caudatum (Figure 77C): Epiphytic on Dictyota, 1.5–

4.6 m depths, ~0.8 km south of shipwreck, Cabeza Ballena, 

Baja California Sur, Coll. J. N. Norris, K. E. Bucher, and 

H. Sleeper (JN-4138b, US Alg. Coll. microscope slide 5223). 

Ceramium caudatum (Figure 77D): Epiphytic on Sargassum sinicola, Puertecitos, Baja California, Coll. J. N. Norris and 

G. Boehlert (JN-3289, US Alg. Coll. microscope slide 5211).

Ceramium aduncum (Figure 78A): Epiphytic on Sargassum, 

low intertidal, Playa Las Conchas (Playa Estación), Puerto 

Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN3191, US Alg. Coll. microscope slide 4763). 

Ceramium clarionense (Figure 78B): Epiphytic on Codium simulans, Isla Clarión, Islas Revillagigedo, Pacific Mexico, 

Coll. H. L. Mason (Mason-75, holotype; UC).

Ceramium caudatum (Figure 78C): Epiphytic on Dictyota, 1.5–

4.6 m depths, ~0.8 km south of shipwreck, Cabeza Ballena, 

Baja California Sur, Coll. J. N. Norris, K. E. Bucher and 

H. Sleeper (JN-4138b, US Alg. Coll. microscope slide 5223).

Ceramium equisetoides (Figure 79A–C): Entangled with Callithamnion, intertidal, tidal platform, Playa Las Conchas 

(Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris 

and K. E. Bucher (JN-3178e, US Alg. Coll. microscope slide 

4666).

Ceramium hamatispinum (Figure 79D–G): Entangled with Gayliella and Polysiphonia, intertidal, inner shallow lagoon of 

Bahía San Carlos, north of Guaymas, Sonora, Coll. E. Y. 

Dawson (EYD-11019b, US Alg. Coll. microscope slide 492).

Ceramium horridulum (Figure 80): Dive to 9 m depth, off “rock 

window” on northwest shore, Puerto Refugio, Isla Ángel de la 

Guarda, Coll. J. N. Norris and K. E. Bucher (JN-5310: A, US 

Alg. Coll.-217345; B, US Alg. Coll. microscope slide 8703).

Ceramium howellii (Figure 81A–C): 0.9–7.6 m depths, Punta la 

Gringa, Bahía de Los Ángeles, Baja California, Coll. J. N. 

Norris and K. E. Bucher (JN-5464b, US Alg. Coll. microscope slide 5271). 

Ceramium howellii (Figure 81D): Dredged 45–55 m depths, off 

Sandstone Point, Isla Guadalupe, off Baja California, Pacific Mexico, Coll. E. Y. Dawson (EYD-8425, US Alg. Coll. 

microscope slide 479).

Ceramium interruptum (Figure 82A): Epiphytic on Gelidiopsis,

intertidal, Cumpleaños Tide Pool, Playa Las Conchas (Playa 

Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and 

K. E. Bucher (JN-4201, US Alg. Coll. microscope slide 4788). 

Ceramium interruptum (Figure 82B–D): Epiphytic on Prionitis,

dive 3–15 m depth, off north end of island, Isla Coronado, 

Bahía de Los Ángeles, Baja California, Coll. H. Sleeper and 

M. Helvey (JN-4404, US Alg. Coll. microscope slide 4794).

Ceramium mazatlanense (Figure 83): Intertidal rocky shelf, 

Ensenada de San Francisco, near Puerto San Carlos, Sonora, 

Coll. E. Y. Dawson (EYD-11031, US Alg. Coll. microscope 

slide 512).

Ceramium obesum (Figure 84A): Intertidal rocky shore, Bahía 

Agua Dulce, north end of Isla Tiburón, Islas de la Cintura 

(holotype: EYD-964, AHFH, now UC).

Ceramium serpens (Figure 84B): Epiphytic of Laurencia, La Paz, 

Baja California Sur (Marchant-67c, CAS, now UC).

Ceramium paniculatum (Figure 85A, C–F): Rock sides and ledges, 

Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher 

(JN-4396, US Alg. Coll. microscope slide 8704). 

Ceramium paniculatum (Figure 85B): Cumpleaños Tide Pool, 

Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN-4539, US Alg. 

Coll. microscope slide 4258).

Ceramium periconicum (Figure 86A): Dredged, Bahía San Lucas, 

Baja California Sur, Coll. E. Y. Dawson (EYD-6851a, US 

Alg. Coll. microscope slide 557). 

Ceramium periconicum (Figure 86B, C): Epiphytic on Gelidium, 

7.6–18 m depths, Isla la Ventana, Bahía de Los Ángeles, Baja 

California, Coll. J. N. Norris, M. Helvey, and H. Sleeper 

(JN-4436, US Alg. Coll. microscope slide 8705).

Ceramium procumbens (Figure 87): Epiphytic on Dichotomaria 

spathulata, dive off small cove, to 6 m depth, Punta Cirio, 

south of Puerto Libertad, Sonora, Coll. J. N. Norris, K. E. 

Bucher, and D. Moore (JN-4897, US Alg. Coll. microscope 

slide 8706).

Ceramium sinicola (Figure 88): Epiphytic on Laurencia iriei, 

Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher 

(JN-4584, US Alg. Coll. microscope slide 4798).

Corallophila bella (Figure 89C): Cast ashore, Guaymas, Sonora 

(type: Marchant-85, CAS, now UC).

Gayliella fimbriata (Figure 90): Epiphytic on Padina, dive intertidal to 9 m depth, off rocky point inside SE side of Punta 

Pelícano, vicinity of Puerto Peñasco, Sonora, Coll. J. N. 
486 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Norris, K. E. Bucher, and D. Moore (JN-5062, US Alg. Coll. 

microscope slide 5263).

Gayliella species A (Figure 91A): Epiphytic on Sargassum, dive 

3.0–15 m depths, off north end of island, Isla Coronado, 

Bahía de Los Ángeles, Baja California, Coll. H. Sleeper 

and M. Helvey (JN-4406, US Alg. Coll. microscope slide 

5233). 

Gayliella species A (Figure 91B): Epiphytic on Dichotomaria 

spathulata, 1.5–4.6 m depths, rock reef, west side of Punta 

Robinson (~2.5 km east of Puerto Libertad), Sonora, Coll. 

J. N. Norris and K. E. Bucher (JN-4834, US Alg. Coll. 

microscope slide 5250). 

Gayliella species A (Figure 91C, D): Dive 1.5–4.6 m depths, ~0.8 

km south of shipwreck, Cabeza Ballena, Baja California Sur, 

Coll. J. N. Norris, K. Bucher, and H. Sleeper (JN-4139, US 

Alg. Coll. microscope slide 5225).

Gayliella recticortica (Figure 92): Tide pools, rocky shore on 

south side of bay, Ensenada Bocochibampo, Sonora, Coll. 

E. Y. Dawson (EYD-46-501, AHFH, now UC).

Gayliella taylorii (Figure 93): Intertidal rock shelf with tide 

pools, Ensenada de San Francisco, between Bahía San Carlos and Guaymas, Sonora, Coll. E. Y. Dawson (EYD-1962: 

A, US Alg. Coll. microscope slide 441; B, US Alg. Coll. 

microscope slide 440).

Pterothamnion pectinatum (Figure 95A, C): Epiphytic on Sebdenia flabellata, 0.9–10.6 m depths, south end of Isla Estanque, Coll. J. N. Norris and K. E. Bucher (JN-5512, US 

Alg. Coll. microscope slide 4706).

Pterothamnion pectinatum (Figure 95B, D): Epiphytic or entangled with Sporochnus neushulii, 23 m depth, off west side 

of Roca Blanca, Puerto Refugio, Isla Ángel de la Guarda, 

Coll. J. N. Norris (JN-5263: B, US Alg. Coll. microscope 

slide 4711; D, US Alg. Coll. microscope slide 4710).

Dasya pedicellata subsp. stanfordiana (Figure 96A): Dive to 

13.7 m depth, attached to seashells on muddy bottom; 

Canal de Infiernillo, midway between Isla Tiburón and west 

of Camp Viboras, Sonora, Coll. G. L. Kooyman and E. Sinnett (JN-4731, US Alg. Coll.-159017). 

Dasya pedicellata subsp. stanfordiana (Figure 96B, C, E): Dive 

to 13.7 m depth, attached to seashells on muddy bottom; 

Canal de Infiernillo, midway between Isla Tiburón and west 

of Camp Viboras, Sonora, Coll. G.L. Kooyman and E. Sinnett (JN-4724: B, US Alg. Coll.-159015; C, E. US Alg. Coll. 

microscope slide 4855).

Dasya pedicellata subsp. stanfordiana (Figure 96D): Epiphytic 

on other algae, beach drift, Desemboque de San Ignacio 

(Seri village), Sonora, Coll. R. E. Schultes, R. S. Felger, and 

A. T. Weil (JN-5165, US Alg. Coll. microscope slide 4852).

Dasya pedicellata subsp. stanfordiana var. nudicaulis (Figure 

97): Dive 15–21 m depths, off rocky shoreline, west side 

of Roca Blanca, Puerto Refugio, Isla Ángel de la Guarda, 

Islas de la Cintura, Coll. J. N. Norris (JN-5800, US Alg. 

Coll.-159009).

Dasya sinicola var. californica (Figure 98A): Intertidal reef, ~30 

m south of “La Jolla Beach Club,” south side of La Jolla 

bay, La Jolla, California, Coll. E. Y. Dawson (drawn from 

topotype specimen: EYD-303, AHFH, now UC).

Dasya spinigera (Figure 98B, C): On sand bottom, dredged 20 

m depth, Bahía San Lucas, Baja California Sur, Coll. E. Y. 

Dawson (EYD-6845a, AHFH, now UC).

Dasya sinicola var. sinicola (Figure 98D): Rocky intertidal shore, 

south side of bay, Ensenada Bocochibampo, near Guaymas, 

Sonora (EYD-468, AHFH, now UC).

Dasya sinicola var. californica (Figure 99A): Intertidal rock platform, Playa Hermosa, (west side of Playa Hermosa Hotel), 

Puerto Peñasco, Sonora, Coll. J. N. Norris (JN-3696, US 

Alg. Coll.-159037).

Dasya sinicola var. sinicola (Figure 99B, C): Hand dredge 9.1–

22.8 m, Isla Las Ánimas (Isla San Lorenzo del Norte), Islas 

de San Lorenzo, off Baja California, Coll. E. Y. Dawson, R. 

Banks, E. Wilson, and J. Sloan (California Department of 

Fish and Game; M/V Alaska expedition) (EYD-26119, US 

Alg. Coll. microscope slide 792).

Heterosiphonia crispella var. laxa (Figure 100A, B, D): Epiphytic on Padina, west side of small cove, dive to 6 m depth, 

Punta Cirio, south of Puerto Libertad, Sonora, Coll. J. N. 

Norris, K. E. Bucher, and D. Moore (JN-4898, US Alg. Coll. 

microscope slide 4889).

Heterosiphonia crispella var. laxa (Figure 100C, E): 1.5–4.6 m

depths, ~0.8 km [~0.5 mile] south of shipwreck, Cabeza 

Ballena, Baja California Sur, Coll. J. N. Norris, K. E. Bucher, 

and H. Sleeper (C, JN-4155, US Alg. Coll. microscope slide 

4883; E,.JN-4155, US Alg. Coll. microscope slide 4884).

Heterosiphonia erecta (Figure 101A): Dive to 10.6–30 m depths, 

Islas de Los Gemelos, Bahía de Los Ángeles, Baja California, 

Coll. J. N. Norris, H. Sleeper, and W. Baines (JN-4746, US 

Alg. Coll.-160012). 

Heterosiphonia erecta (Figure 101B): Epiphytic on Botryocladia, dive 10.6–30 m depths, Islas de Los Gemelos, Bahía de 

Los Ángeles, Baja California, Coll. J. N. Norris, H. Sleeper, 

and W. Baines (JN-4750, US Alg. Coll. microscope slide 

4879). 

Heterosiphonia erecta (Figure 101C, D): 3.0–15 m depths, dive 

off north end of island, Isla Coronado, Bahía de Los Ángeles, Baja California, Coll. H. Sleeper and M. Helvey (JN4417: C, US Alg. Coll. microscope slide 4885; D, US Alg. 

Coll. microscope slide 4886).
NUMBER 96 • 487

Apoglossum gregarium (Figure 102): On a hydroid dredged 

from 8–16 m, Isla Las Ánimas (Isla San Lorenzo del Norte), 

Islas de San Lorenzo, Coll. E. Y. Dawson (type of Hypoglossum gregarium E. Y. Dawson) (EYD-26123, US Alg. Coll. 

microscope slide 791).

Branchioglossum bipinnatifidum (Figure 103A, B): 9 m depth, 

off rocky point, SE side of Punta Pelícano, vicinity of Puerto 

Peñasco, Sonora, Coll. J. N. Norris, K. E. Bucher, and 

D. Moore (A, JN-5036, US Alg. Coll.-217354; B, US Alg. 

Coll. microscope slide 4615). 

Branchioglossum bipinnatifidum (Figure 103C): Rock sides and 

ledges, Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. 

Bucher (JN-4309, US Alg. Coll. microscope slide 4619).

Branchioglossum bipinnatifidum (Figure 103D): Intertidal rock 

platform, Playa Hermosa, Puerto Peñasco, Sonora, Coll. 

J. N. Norris and K. Bucher (JN-3987, US Alg. Coll. microscope slide 4625).

Branchioglossum undulatum (Figure 104): Epiphytic on Sargassum stipe, 6 m depth, west side of small cove, Punta Cirio, 

south of Puerto Libertad, Sonora, Coll. J. N. Norris, K. E. 

Bucher, and D. Moore (JN-4920, US Alg. Coll. microscope 

slide 4617).

Caloglossa apomeiotica (Figure 105A): Mangaratiba City, Rio 

de Janeiro (state), Brazil, Coll. C. F. D. Gurgel (=D. M. 

Krayesky-73) (US Alg. Coll.). 

Caloglossa apomeiotica (Figure 105B, C): Isla Perico, Balboa, 

Pacific Panama, Coll. B. S. Wysor (=D. M. Krayesky-64) (US 

Alg. Coll.).

Erythroglossum californicum (Figure 106): Drift, Desemboque 

de San Ignacio (Seri village), Sonora, Coll. J. N. Norris, K. E. 

Bucher, and D. Coon (JN-6578a, US Alg. Coll.-217358).

Grinnellia lanceolata (Figure 107A, C, D): Dredged from 12–16 

m, off Isla Salsipuedes (Islas de San Lorenzo), Coll. E. Y. 

Dawson (type of Apoglossum punctatum: EYD-26143, US 

Alg. Coll. microscope slide 779).

Grinnellia lanceolata (Figure 107B): Dredged to 50 m, off Punta 

Gorda, Baja California, Pacific Mexico, Coll. E. Y. Dawson 

(holotype of Grinnellia lanceolata: EYD-626-40, AHFH 

now UC).

Hypoglossum attenuatum var. abyssicola (Figure 108A): About 

13.7 m depth, muddy bottom, attached to seashells, Canal 

de Infiernillo midway between Isla Tiburón and west of 

Campo Viboras, Sonora, Coll. G. L. Kooyman and E. Sinnett (JN-4722, US Alg. Coll.-160075).

Hypoglossum attenuatum var. abyssicola (Figure 108B): Hand 

dredge 18.3–30.5 m depths, Isla San Lorenzo (Isla San 

Lorenzo del Sur), Islas de San Lorenzo, Coll. E. Y. Dawson, R. Banks, E. Wilson, and J. Sloan (EYD-26163, US Alg. 

Coll. microscope slide 774).

Hypoglossum attenuatum var. abyssicola (Figure 108C): Entangled with Sorella pinnata, beach drift, Desemboque de 

San Ignacio (Seri village), Sonora, Coll. R. E. Schultes, R. S. 

Felger, and A. T. Weil (JN-5156a, US Alg. Coll. microscope 

slide 4609).

Hypoglossum attenuatum var. abyssicola (Figure 108D, E): D. 

Hand dredge 9.1–22.8 m depths, Isla Las Ánimas (Islas San 

Lorenzo del Norte), Islas de San Lorenzo, Coll. E. Y. Dawson, R. Banks, E. Wilson, and J. Sloan (EYD-26117 (♂, ♀), 

US Alg. Coll. microscope slide 793).

Myriogramme divaricata (Figure 109A): 0.9–10.6 m depths, 

dive off the south end of Isla Estanque, Islas de la Cintura, 

Coll. J. N. Norris and K. E. Bucher (JN-5583a, US Alg. 

Coll.-217360).

Myriogramme auricularis (Figure 109B, C): Dredged from 

19–30 m, Isla San Lorenzo del Sur, Coll. E. Y. Dawson, 

R. Banks, E. Wilson, and J. Sloan (holotype: EYD-26167, 

US Alg. Coll. microscope slide 771).

Myriogramme sp. (Figure 109D): Dive to 6 m depth, off west 

side of small cove, Punta Cirio, south of Puerto Libertad, 

Sonora, Coll. J. N. Norris, K. E. Bucher, and D. Moore (JN4901, US Alg. Coll. microscope slide 5289).

Phycodrys amplissima (Figure 110A): Cast ashore, beach in 

front of Seri village, Desemboque de San Ignacio, Sonora, 

Coll. J. N. Norris, K. E. Bucher, and D. Coon (JN-6578b, 

US Alg. Coll.-217347). 

Phycodrys amplissima (Figure 110B): Dredged from depth of 

9.0–36 m, Isla San Esteban, Coll. L. Pinkas, E. Smith, and 

D. Miller (California Department of Fish and Game; M/V 

Alaska expedition) (isotype: EYD-21580, US Alg. Coll. 

microscope slide 635).

Phycodrys simplex (Figure 111): Dredged in 22–44 m, Puerto 

Refugio, Isla Ángel de la Guarda, Coll. E. Y. Dawson (holotype: EYD-183-40, AHFH, now UC).

Polyneurella hancockii (Figure 112): Dive to 13.7 m depth, attached to seashells, muddy bottom; Canal de Infiernillo, 

midway between Isla Tiburón and west of Camp Viboras, 

Sonora, Coll. G. L. Kooyman and E. Sinnett (A, JN-4720, 

US Alg. Coll.-217356; B, JN-4727, US Alg. Coll.-217357; 

C, JN-4725, US Alg. Coll. microscope slide 5283; D, JN4720, US Alg. Coll. microscope slide 5285).

Schizoseris pygmaea (Figure 113A, B): On intertidal rocks, 

Punta Pelícano, vicinity of Puerto Peñasco, Sonora, Coll. 

J. N. Norris and K. E. Bucher (JN-3823: A, US Alg. Coll. 

microscope slide 5282; B, US Alg. Coll.-160889).
488 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Schizoseris pygmaea (Figure 113C): Mid to low intertidal rock 

platform and tide pools, Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. 

Bucher (JN-3902, US Alg. Coll. microscope slide 5286).

Sorella pinnata (Figure 114A–C): Dive to 10.6–30 m depths, 

Islas de Los Gemelos, Bahía de Los Ángeles, Baja California, 

Coll. J. N. Norris, H. Sleeper, and W. Baines (JN-4749, US 

Alg. Coll. microscope slide 4642). 

Sorella pinnata (Figure 114D): Beach drift, Desemboque de San 

Ignacio (Seri village), Sonora, Coll. R. E. Schultes, R. S. 

Felger, and A. T. Weil (JN-5154, US Alg. Coll. microscope 

slide 4643). 

Sorella pinnata (Figure 114E): 7.6–9.0 m depths, attached to 

rocks, west side of large rock, Rocas Consag, Coll. D.G. 

Lindquist (JN-3131, US Alg. Coll. microscope slide 4645).

Taenioma perpusillum (Figure 115): On intertidal rocks, near 

inner wharf of inner bay, Topolobampo, Sinaloa, Coll. E. Y. 

Dawson (A,C, EYD-10891, US Alg. Coll. microscope slide 

569; B, EYD-10908, US Alg. Coll. microscope slide 570).

Platysiphonia decumbens (Figure 116A): Intertidal to 9 m depth, 

NW of rock window on shore, Puerto Refugio, Isla Ángel de 

la Guarda, Coll. J. N. Norris and K. E. Bucher (JN-5324b, 

US Alg. Coll. microscope slide 5290).

Platysiphonia decumbens (Figure 116B, C): Hand dredged

9.1–22.8 m depths, Isla Las Ánimas (Islas San Lorenzo del 

Norte), Islas de San Lorenzo, Coll. E. Y. Dawson, R. Banks, 

E. Wilson, and J. Sloan (EYD-26116, US Alg. Coll. microscope slide 794).

Chondria acrorhizophora (Figure 117A): Eureka, near La Paz, 

Baja California Sur (isotype: D.R. Marchant-44, US Alg. 

Coll.-56205).

Chondria acrorhizophora (Figure 117B): Drift, Desemboque de 

San Ignacio, Sonora, Coll. J. N. Norris, K. E. Bucher, and 

D. Coon (JN-6577, US Alg. Coll.-158967).

Digenea simplex (Figure 119): Cumpleaños Tide Pool, Playa Las 

Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. 

J. N. Norris, K. E. Bucher, and L. Gleye (both JN-4204: A, 

US Alg. Coll.-159105; B, US Alg. Coll.-159104).

Herposiphonia littoralis (Figure 120): Epiphytic on Padina, 

beach drift, Desemboque de San Ignacio (Seri village), Sonora, Coll. R. E. Schultes, R. S. Felger, and A. T. Weil (JN5153, US Alg. Coll. microscope slide 4946).

Herposiphonia plumula var. plumula (Figure 121): Epiphytic 

on Sargassum sinicola var. camouii, Cumpleaños Tide Pool, 

Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN-4301, US Alg. 

Coll. microscope slide 4913).

Herposiphonia plumula var. parva (Figure 122): Lady’s Harbor, 

Santa Cruz Island, California Channel Islands, Coll. G. J. 

Hollenberg (holotype: GJH-1337, US Alg. Coll.-61192; US 

Alg. Coll. microscope slides 3440–3446).

Herposiphonia spinosa (Figure 123A): Cumpleaños Tide Pool, 

Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN-4390, US Alg. 

Coll. microscope slide 4912).

Herposiphonia spinosa (Figure 123B): Intertidal platform, Playa 

Las Conchas (Playa Estación), Puerto Peñasco, Sonora, 

Coll. J. N. Norris and K. E. Bucher (JN-3175, US Alg. Coll. 

microscope slide 4907).

Laurencia aguilar-rosasorum (Figure 124A): Rocky intertidal 

platform and tide pools, Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and 

K. E. Bucher (JN-4369, US Alg. Coll.-217740). 

Laurencia fenicalii (Figure 124B): On rocks, Cumpleaños Tide 

Pool, Playa Las Conchas (Playa Estación), Puerto Peñasco, 

Sonora, Coll. J. N. Norris and K. E. Bucher (JN-4515, US 

Alg. Coll.-217741).

Laurencia iriei (Figure 124C): On rocks, Cumpleaños Tide 

Pool, Playa Las Conchas (Playa Estación), Puerto Peñasco, 

Sonora, Coll. J. N. Norris and K. E. Bucher (JN-4519, US 

Alg. Coll.-217742). 

Laurencia johnstonii (Figure 124D): On rocks and tidal platform, Cumpleaños Tide Pool, Playa Las Conchas (Playa 

Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris (JN4068, US Alg. Coll.-160140).

Osmundea estebaniana (Figure 125A): Intertidal to 6 m depth, 

Isla Mejia, off north end of Isla Ángel de la Guarda, Coll. 

J. N. Norris and K. E. Bucher (JN-5832, US Alg. Coll.-

160119). 

Osmundea estebaniana (Figure 125B): 9–23 m dive, off west 

side of Roca Blanca, Puerto Refugio, Isla Ángel de la 

Guarda, Coll. J. N. Norris, J. Paul, and K. Robertson (JN5273, US Alg. Coll.-160111).

Osmundea sinicola (Figure 125C): Cast ashore, Bahía San Carlos, Sonora, Coll. Dana Bean, s.n. (US Alg. Coll.-30106).

Palisada paniculata (Figure 126B, C): Cumpleaños Tide Pool, 

Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and R. W. Hoshaw (JN-5006, US 

Alg. Coll.-160223).

Palisada pedrochei (Figure 126D): Intertidal rock platform, 

Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (holotype: JN5879, US Alg. Coll.-160250).

Neosiphonia cheloniae (Figure 127): Epizoic on dorsal surface 

of head and flippers of a living female black sea turtle, Canal 

de Infiernillo, vicinity of Campo Ona, Sonora (opposite the 
NUMBER 96 • 489

east coast of Isla Tiburón), Coll. R. S. Felger, E. W. Moser, 

and E. Méndez (JN-4765.5, US Alg. Coll. microscope slide 

5046).

Neosiphonia concinna (Figure 128A): On other intertidal algae, 

near Scripps Institution of Oceanography, La Jolla, California, Coll. G.J. Hollenberg (holotype: GJH-2015, US Alg. 

Coll.-61210, US Alg. Coll. microscope slide 1225). 

Neosiphonia confusa (Figure 128B): Corona del Mar, California, Coll. G. J. Hollenberg (topotype: GJH-1383, US Alg. 

Coll.-64866). 

Neosiphonia johnstonii var. johnstonii (Figure 128C): Puerto 

Libertad, Sonora, Coll. E. Y. Dawson (EYD-670, AHFH, 

now UC). 

Neosiphonia eastwoodae (Figure 128D): Epiphytic on various 

algae, False Bay (now Mission Bay), San Diego, California 

(isotype: Polysiphonia snyderae Kylin, 1941; Collins et al., 

1899: Fasciculus 13, No. 638, US Alg. Coll-64991). 

Neosiphonia masonii (Figure 128E): North side of reef, off southwest end of Isla Guadalupe, Pacific Baja California (EYD4073, AHFH, now UC). 

Neosiphonia masonii (Figure 128F): Off Islote Zapato, Isla Guadalupe (EYD-19277, AHFH, now UC).

Neosiphonia flaccidissima (Figure 129A): 1.5–6 m depths, 

Nueva Guaymas, Sonora, Coll. D. Evanson (JN-4267, US 

Alg. Coll. microscope slide 5029). 

Neosiphonia flaccidissima (Figure 129B, C): Epiphytic on Padina, 1.5–6 m depths, Nueva Guaymas, Sonora, Coll. 

D. Evanson (JN-4270, US Alg. Coll. microscope slide 5031).

Neosiphonia savatieri (Figure 130A): Intertidal platform and

Cumpleaños Tide Pool, Playa Las Conchas (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris (JN-4195, US 

Alg. Coll. microscope slide 5027). 

Neosiphonia savatieri (Figure 130B): 1.5–6 m depths, Nueva 

Guaymas, Sonora, Coll. D. Evanson (JN-4266, US Alg. 

Coll. microscope slide 5030).

Neosiphonia confusa (Figure 131A): Epizoic on sand dollar Encope grandis, in sand tidal channels, Bahía La Choya (Bahía 

Cholla), vicinity of Puerto Peñasco, Sonora (JN-5577, US 

Alg. Coll. microscope slide 5052). 

Neosiphonia confusa (Figure 131B): On NASA buoy, anchored 

off Laboratorio de Biología Marina, Playa Las Conchas 

(Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris 

(JN-3835, US Alg. Coll. microscope slide 5000). 

Neosiphonia simplex (Figure 131C): Mid intertidal rock platform and tide pools, from laboratory to Cumpleaños Tide 

Pool, Playa Las Conchas (Playa Estación), Puerto Peñasco, 

Sonora, Coll. J. N. Norris and K. E. Bucher (JN-5098b, US 

Alg. Coll. microscope slide 4996). 

Neosiphonia simplex (Figure 131D): 9 m depth, off rocky point, 

SE side of Punta Pelicano, vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris, K. E. Bucher, and D. Moore (JN5038, US Alg. Coll. microscope slide 4994).

Neosiphonia mexicana (Figure 132A): A. Bahía Sulphur, Isla 

Clarión, Islas Revillagigedo, Pacific Mexico, Coll. J. T. 

Howell (paratype: JTH-238a, AHFH, now UC).

Neosiphonia mexicana (Figure 132B–D): On rocks with other 

minute algae, low intertidal, Isla Estanque (Pond Island), 

off southeastern end of Isla Ángel de la Guarda, Coll. E. Y. 

Dawson (holotype: EYD-430-40, AHFH-62, now UC).

Neosiphonia paniculata (Figure 132E): Esquimalt, near inner 

harbor of Victoria, Vancouver Island, British Columbia, and 

Juan de Fuca Strait (between Vancouver Island and Olympic 

Peninsula, Washington).

Polysiphonia sonorensis (Figure 132F): Drift, southeastern shore 

of Bahía Empalme, Sonora, Coll. F. Drouet and D. Richards 

(Drouet & Richards-3426a: holotype F; isotype: US Alg. 

Coll.-66807, microscope slides 1237–1239).

Neosiphonia paniculata (Figure 133): Epiphytic on Encope 

grandis (sand dollar), sand-mud flats, Bahía La Choya 

(Bahía Cholla), vicinity of Puerto Peñasco, Sonora, Coll. 

J. Kudenov and J. N. Norris (JN-4552, US Alg. Coll.-

160578).

Polysiphonia hollenbergii (Figure 134): 7.6 m depth, Isla La 

Ventana, Bahía de Los Ángeles, Baja California, Coll. J. N. 

Norris and G. Boehlert (holotype: JN-2998b, US Alg. Coll. 

microscope slide 5004).

Polysiphonia pacifica var. delicatula (Figure 135): Epiphytic on 

Gelidium johnstonii, 3.3 m depth, rock reef, Cabo Lobos, 

vicinity of Puerto Libertad, Coll. J. N. Norris and K. E. Bucher (JN-4848a, US Alg. Coll. microscope slide 4260).

Polysiphonia scopulorum var. villum (Figure 136A): Mid intertidal, tidal platform and Cumpleaños Tide Pool, Playa Las 

Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. 

J. N. Norris and K. E. Bucher (JN-5098a, US Alg. Coll. 

microscope slide 4995). 

Polysiphonia scopulorum var. villum (Figure 136B): Intertidal, 

tidal platform fronting Laboratorio de Biología Marina, 

Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris (JN-3744, US Alg. Coll. microscope 

slide 5025).

Pterosiphonia dendroidea (Figure 137A): Islas de Los Gemelos, 

Bahía de Los Ángeles, Baja California, Coll. J. N. Norris, 

H. Sleeper, and W. Baines (JN-4742, US Alg. Coll. microscope slide 4899). 

Pterosiphonia californica (Figure 137B): 9 m depth, off rocky 

point, SE side of Punta Pelícano, vicinity of Puerto Peñasco, 

Sonora, Coll. J. N. Norris, K. E. Bucher, and D. Moore (JN5021, US Alg. Coll. microscope slide 4900).
490 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Pterosiphoniella williamsii (Figure 138A–C): Dive 1.5–4.6 m 

depths, ~0.8 km south of shipwreck, Cabeza Ballena, Baja 

California Sur, Coll. J. N. Norris and K. E. Bucher (JN4126, US Alg. Coll. microscope slide 4914). 

Pterosiphoniella williamsii (Figure 138D): Intertidal rocks, in 

front of wrecked Japanese ship, Inari Maru 10, Cabeza 

Ballena, Baja California Sur, Coll. J. N. Norris and K. E. 

Bucher (JN-4103, US Alg. Coll. microscope slide 4915).

Amplisiphonia? pacifica (Figure 139): Epiphytic on Palisada paniculata, north side of Puerto Calamajue, Baja California, 

Coll. J. N. Norris and K. E. Bucher (JN-4682, US Alg. Coll. 

microscope slide 4984).

Veleroa subulata (Figure 140): On hydroid, dredged 22 m depth, 

Bahía Tepoca, Sonora, Coll. E. Y. Dawson (holotype: EYD381d-40, AHFH-63, now UC).

Spyridia cf. filamentosa (Figure 141A): Intertidal rocks fronting 

Laboratorio de Biología Marina, Playa Las Conchas (Playa 

Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and 

K. E. Bucher (JN-3140, US Alg. Coll.-160963).

Spyridia cf. filamentosa (Figure 141B): Mudflats, Bahía La 

Choya (Bahía Cholla), vicinity of Puerto Peñasco, Sonora, 

Coll. J. N. Norris (JN-4060, US Alg. Coll.-160981).

Spyridia cf. filamentosa (Figure 141C, D): Epiphytic, intertidal, in front of Laboratorio de Biología Marina, Playa Las 

Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. 

J. N. Norris (JN-4075, US Alg. Coll. microscope slide 

4836).

Spyridia cf. filamentosa (Figure 141E, F): Intertidal, tidal platform, Playa Hermosa (~0.4 km west of Playa Hermosa 

Hotel), vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN-4019, US Alg. Coll. microscope 

slide 4834).

Anotrichium furcellatum (Figure 142): Growing on shell, Islas 

de Los Gemelos, Bahía de Los Ángeles, Baja California, 

Coll. H. Sleeper and M. Helvey (JN-4487, US Alg. Coll. 

microscope slide 4969).

Anotrichium secundum (Figure 143A): Beach drift, Desemboque 

de San Ignacio, Sonora, Coll. R. E. Schultes, R. S. Felger, 

and A. T. Weil (JN-5187, US Alg. Coll. microscope slide 

4952).

Anotrichium secundum (Figure 143B): Epizoic on sponge, intertidal, Playa Hermosa (~0.4 km west of Playa Hermosa 

Hotel), Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. 

Bucher (JN-4032, US Alg. Coll. microscope slide 4961).

Griffithsia pacifica (Figure 144A): Epiphytic on Gelidium, beach 

drift, Desemboque de San Ignacio (Seri village), Sonora, 

Coll. R. E. Schultes, R. S. Felger, and A. T. Weil (JN-5159, 

US Alg. Coll. microscope slide 4980). 

Griffithsia pacifica (Figure 144B): Beach drift, Desemboque de 

San Ignacio (Seri village), Sonora, Coll. R. E. Schultes, R. S. 

Felger, and A. T. Weil (JN-5148, US Alg. Coll. microscope 

slide 4955).

Lejolisia hoshawii (Figure 145): Epiphytic on Sargassum in the 

drift, Playa Hermosa, Puerto Peñasco, Sonora, Coll. A. E. 

Dennis (type illustrations EYD-27530, US Alg. Coll. microscope slide 989).

Tiffaniella saccorhiza (Figure 146A, B): Bahía de Los Ángeles, 

Baja California, Coll. E. Y. Dawson (EYD-46-1330, US Alg. 

Coll. microscope slide 917).

Pleonosporium globliferum (Figure 147A, C): Dive 1.5–4.6 m 

depths, ~0.8 km south of shipwreck, Cabeza Ballena, Baja 

California Sur, Coll. J. N. Norris and K. E. Bucher (JN4147, US Alg. Coll. microscope slide 4682).

Pleonosporium globliferum (Figure 147B): Epiphytic on Dictyopteris undulata, Punta Los Frailes, Baja California Sur, 

Coll. V. Paul (JN-7175a, US Alg. Coll. microscope slide 

4673).

Pleonosporium mexicanum (Figure 148): Lowermost intertidal 

on small reef, 3 km north of Belmar Hotel, Playa de Olas 

Atlas, vicinity of Mazatlán, Sinaloa (holotype: EYD-3610,

US Alg. Coll. microscope slide 398).

Pleonosporium vancouverianum (Figure 149): Dive 10.6–30 m 

depths, Islas de Los Gemelos, Bahía de Los Ángeles, Baja 

California, Coll. J. N. Norris (JN-4745, US Alg. Coll. microscope slides 4690, 4689). 

Gelidium crinale (Figure 150F): Intertidal, Punta Estrella, ~3.2 

km south of San Felipe, Baja California, Coll. J. N. Norris 

and G. Boehlert (JN-3310, US Alg. Coll.-159270).

Gelidium crinale (Figure 150G): Intertidal, on tidal platforms, 

Playa Hermosa, vicinity of Puerto Peñasco, Sonora, Coll. J. 

N. Norris and K. E. Bucher (JN-3483, US Alg. Coll.-159274).

Gelidium decompositum (Figure 151): Rocky intertidal, Puerto 

Calamajue, Baja California, Coll. J. N. Norris and K. E. 

Bucher (JN-4611a, US Alg. Coll.-159296). 

Gelidium johnstonii (Figure 152A): 3.0–7.6 m depths, dive off 

SE end of Isla San Esteban, Islas de la Cintura, Coll. J. N. 

Norris and K. E. Bucher (JN-5539, US Alg. Coll.-159337). 

Gelidium johnstonii (Figure 152B): Low intertidal, tidal platform 

fronting Laboratorio de Biología Marina, Playa Las Conchas 

(Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris 

and K. E. Bucher (JN-3796, US Alg. Coll.-159339).

Gelidium mcnabbianum (Figure 153A, B): Rocky shore, fronting Laboratorio de Biología Marina, Playa Las Conchas 
NUMBER 96 • 491

(Playa Estación), Puerto Peñasco, Coll. E. Y. Dawson (EYD27340, US Alg. Coll.-40743). 

Gelidium pusillum (Figure 153C): On tidal platform, Playa Hermosa, vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris 

and K. E. Bucher (JN-3482, US Alg. Coll.-159272).

Pterocladia sonorense (Figure 156): On intertidal rocks, tidal 

platform fronting Laboratorio de Biología Marina, Playa 

Las Conchas (Playa Estación), Puerto Peñasco, Sonora, 

Coll. E. Y. Dawson (EYD-27304, US Alg. Coll.-40860).

Pterocladiella capillacea (Figure 157): Rocky intertidal, north 

side of Puerto Calamajue, Baja California, Coll. J. N. Norris 

and K. E. Bucher (JN-4611b, US Alg. Coll.-159295).

Hypnea cervicornis (Figure 158): Rocky reef Playa Tucson, 

Bahía La Choya (Bahía Cholla) on bay side of Punta Pelícano, vicinity of Puerto Peñasco, Sonora, Coll. E. Y. Dawson (EYD-27213, US Alg. Coll.-40586).

Dicranema rosaliae (Figure 159A): Intertidal rocks near inner 

wharf of the inner bay, Topolobampo, Sinaloa, Coll. E. Y. 

Dawson (EYD-10897, US Alg. Coll.-7173). 

Dicranema rosaliae (Figure 159C): Tidal platform in sand-covered areas, Playa Hermosa, Puerto Peñasco, Sonora, Coll. 

J. N. Norris and K. E. Bucher (JN-3263, US Alg. Coll. 

microscope slide 4534).

Dudresnaya colombiana (Figure 160A, C): 1–10 m depths, 

south end of Isla Estanque, Coll. J. N. Norris and K. E. 

Bucher (JN-5480: A, US Alg. Coll.-8760; C, US Alg. Coll. 

microscope slide 3769).

Dudresnaya colombiana (Figure 160B): 15–23 m depths, east 

end of Isla Mejia, Isla Ángel de la Guarda, Coll. J. N. Norris, J. Paul, and K. Robertson (JN-5680, US Alg. Coll. 

microscope slide 3767).

Chondracanthus acicularis (Figure 161): Rocky reef, Playa 

Tucson, on Bahía La Choya (Bahía Cholla) side of Punta 

Pelícano, vicinity of Puerto Peñasco, Sonora, Coll. E. Y. 

Dawson (EYD-27263, US Alg. Coll.-40576).

Chondracanthus squarrulosus (Figure 162A, B): Intertidal platform, Playa Hermosa, Puerto Peñasco, Sonora, Coll. J. N. 

Norris and J. Kudenov (JN-3690: A, US Alg. Coll.-159405; 

B, US Alg. Coll.-159404). 

Chondracanthus squarrulosus (Figure 162C): 3.3 m depth, Puertecitos, Baja California, Coll. J. N. Norris and G. Boehlert 

(JN-3298, US Alg. Coll.-159444).

Chondracanthus squarrulosus (Figure 162D): Punta La Gringa, 

Bahía de los Ángeles, Baja California, Coll. J. N. Norris and 

K. E. Bucher (JN-3026, US Alg. Coll.-159478).

Chondracanthus squarrulosus (Figure 162E): In sandy pockets 

among rocks, 3.3 m depth, La Mona, Bahía de Los Ángeles, 

Baja California, Coll. J. N. Norris (JN-2982, US Alg. Coll.-

159475).

Chondracanthus tepidus (Figure 163): Dive 1.0–7.6 m depths, 

Punta La Gringa, Bahía de Los Ángeles, Baja California, 

Coll. J. N. Norris and K. E. Bucher (JN-5451, US Alg. Coll.-

159488).

Chondracanthus zertuchei (Figure 164): Intertidal, Bahía San 

Francisquito, Baja California, Coll. J. N. Norris (holotype: 

JN-3227, US Alg. Coll.-159436).

Mazzaella diffusa (Figure 165): Dive 15–24 m depths, Isla La 

Ventana, Bahía de Los Ángeles, Baja California, Coll. J. N. 

Norris, M. H. Hommersand, M. Yoshizaki, and G. Boehlert 

(JN-2999: A, US Alg. Coll.-160802; B, US Alg. Coll. microscope slide 5340).

Mazzaella digitata (Figure 166): Cobble shore at mouth of two 

small estuaries on north side of island, Isla Rasa (Islas de la 

Cintura), Coll. E. Y. Dawson (EYD-1045: A, US Alg. Coll.-

12964; B, US Alg. Coll. microscope slide 893).

Mazzaella hancockii (Figure 167): Dive 3–7.6 m depths, southeast side of Isla San Esteban, Coll. J. N. Norris (JN-5563; 

US Alg. Coll.-160803).

Kallymenia baldwinii (Figure 168A): Attached to rock, about 

20 m depth, Bahía Santa Inez, Bahía Concepción, Baja California Sur, Coll. W. Baldwin (holotype: EYD-25819; US 

Alg. Coll.-40928). 

Kallymenia bleckii (Figure 168B): 15 m depth, off Punta Púlpito 

(~12.5 km north of Punta San Basilio), Baja California Sur, 

Coll. John Bleck (holotype: EYD-25919; US Alg. Coll.-40927).

Kallymenia pertusa (Figure 169): Dive 15–23 m depths, off east 

end of Isla Mejía, northern end of Isla Ángel de la Guarda, 

Coll. J. N. Norris, J. Paul, and K. Robertson (JN-5667, US 

Alg. Coll.-217346).

Pugetia mexicana (Figure 170A): Dive 15–22 m depths, off east 

end of Isla Mejía, northern end of Isla Ángel de la Guarda, 

Coll. J. N. Norris, J. Paul, and K. Robertson (JN-5668, US 

Alg. Coll.-217349). 

Pugetia mexicana (Figure 170B): Dive off small islet, 4.6–26 m 

depths, Puerto Refugio, Isla Ángel de la Guarda, Coll. J. N. 

Norris (JN-5362, US Alg. Coll.-160774).

Ahnfeltiopsis hancockii (Figure 171A): Intertidal rocky shore and 

cobble beach, Punta San Felipe (near San Felipe), Baja California, Coll. E. Y. Dawson (EYD-405, US Alg. Coll.-208111).

Ahnfeltiopsis hancockii (Figure 171B): Bahía San Francisquito, 

Baja California, Coll. J. N. Norris (JN-3228, US Alg. Coll.-

159896).
492 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Ahnfeltiopsis serenei (Figure 172): Isla San Benedicto, Islas Revillagigedo, Pacific Mexico (EYD-12058, AHFH, now UC).

Gymnogongrus johnstonii (Figure 173A): Intertidal to 7.6 m 

depth, off northeast end of island, Puerto Refugio, Isla 

Ángel de la Guarda, Coll. J. N. Norris and K. E. Bucher 

(JN-6205, US Alg. Coll.-159912).

Gymnogongrus johnstonii (Figure 173B): Intertidal, rocky shoreline, northeast end of island, Puerto Refugio, Isla Ángel de la 

Guarda, Coll. K. E. Bucher (JN-5736, US Alg. Coll.-159906).

Petroglossum parvum (Figure 174): 13–18 m depths, off Isla Salsipuedes (Islas de San Lorenzo), Islas de la Cintura, Coll. 

E. Y. Dawson (EYD-26138: A, B, US Alg. Coll.-78080; C, 

D, US Alg. Coll. microscope slide 783).

Sarcodiotheca dichotoma (Figure 175A, B): Dive to 18 m depth, 

rocky bottom, Isla la Ventana, Bahía de Los Ángeles, Baja 

California, Coll. J. N. Norris, M. Helvey, and H. L. Sleeper 

(JN-4432, US Alg. Coll.-160847). 

Sarcodiotheca dichotoma (Figure 175C): Drift, Desemboque de 

San Ignacio (Seri village), Sonora, Coll. J. N. Norris, K. E. 

Bucher, and D. Coon (JN-6554, US Alg. Coll.-160887). 

Sarcodiotheca furcata (Figure 176): Dive to 9 m depth, Puerto 

Refugio, Isla Ángel de la Guarda, Coll. J. N. Norris and 

K. E. Bucher (JN-5328, US Alg. Coll.-160855). 

Sarcodiotheca furcata (Figure 177A): Dive off small islet, 4.6–26 

m depths, Puerto Refugio, Isla Ángel de la Guarda, Coll. 

J. N. Norris and K. E. Bucher (JN-5349, US Alg. Coll.-

160859). 

Sarcodiotheca furcata (Figure 177B): Dive 15–22 m depths, off 

west side of rocky shoreline of Roca Blanca, Puerto Refugio, 

Isla Ángel de la Guarda, Coll. J. N. Norris (JN-5798, US 

Alg. Coll.-160864). 

Sarcodiotheca gaudichaudii (Figure 178A, B): 1–7.6 m depths, 

Punta la Gringa, Bahía de Los Ángeles, Baja California, 

Coll. J. N. Norris and K. E. Bucher (A, JN-5439a, US Alg. 

Coll.-160874; B, JN-5439b (♂), US Alg. Coll.-160875).

Sarcodiotheca gaudichaudii (Figure 178C): Drift, Desemboque 

de San Ignacio, Sonora, Coll. J. N. Norris, K. E. Bucher, and 

D. Coon (JN-6555, US Alg. Coll.-160877).

Sarcodiotheca taylorii (Figure 179): Dive 7.6–18 m depths, rocky 

substrate, Isla la Ventana, Bahía de Los Ángeles, Baja California, Coll. J. N. Norris, M. Helvey, and H. L. Sleeper (JN4460: A, US Alg. Coll.-160878; B, US Alg. Coll.-160879).

Tacanoosca uncinata (Figure 180A, D): Beach drift at high tide, 

Punta Colorado, near Guaymas, Sonora, Coll. E. Y. Dawson 

(A, EYD-1800 (♂), US Alg. Coll.-7181; D, EYD-1800 (♀), 

US Alg. Coll.-7181).

Tacanoosca uncinata (Figure 180B): On rock, 6 m depth, Punta 

Willard, Bahía San Luís Gonzaga, Baja California, Coll. 

J. N. Norris and K. E. Bucher (JN-5415, US Alg. Coll.-

210494). 

Tacanoosca uncinata (Figure 180C): 3.0–4.6 m depths, Bahia 

San Francisquito, Baja California, Coll. J. N. Norris (JN238, US Alg. Coll.-89992).

Weeksia coccinea (Figure 181A): Drift, Desemboque de San Ignacio (Seri village), Sonora, Coll. J. N. Norris, K. E. Bucher, 

and D. Coon (JN-6546, US Alg. Coll.-159943).

Weeksia templetonii (Figure 182): Dive 3–15 m depths, north 

end of Isla Coronado, Bahía de Los Ángeles, Baja California, Coll. H. Sleeper and M. Helvey (JN-4349, US Alg. 

Coll.-159945).

Cruoriella fissurata (Figure 183): On intertidal rocks, Cabeza 

Ballena, Baja California Sur (holotype: EYD-6830a; AHFH, 

now UC).

Cruoriella mexicana (Figure 184A): Growing on shells, 13–15 

m depths, off South Coronado Island, Islas Los Coronados, 

Baja California, Pacific Mexico (holotype: EYD-4283c, 

Cruoriopsis mexicana; AHFH, now UC). 

Cruoriella mexicana (Figure 184B): Growing on the articulate 

coralline Bossiella, dredged at the type locality (off Isla Coronado Sur, Islas Los Coronados, off northern Baja California) 

along with the type (paratype: EYD-4280, AHFH, now UC).

Metapeyssonnelia mexicana (Figure 185): Playa Las Conchas 

(Playa Estación), Puerto Peñasco, Sonora, Coll. G. J. Hollenberg (GJH-67-54, US Alg. Coll. microscope slide 3109).

Peyssonnelia mexicana (Figure 186A): Binners Cove, Isla Socorro, Islas Revillagigedo, Pacific Mexico, Coll. E. Y. Dawson (EYD-12137, US Alg. Coll.-12357).

Peyssonnelia mexicana (Figure 186B–D): Dredged from 9–22 

m, Isla Las Ánimas (Isla San Lorenzo del Norte), Islas de 

San Lorenzo, Coll. E. Y. Dawson (B, EYD-26098, US Alg. 

Coll. microscope slide 800; C, D, EYD-26099, US Alg. Coll. 

microscope slide 799).

Peyssonnelia orientalis (Figure 187A, B): Northeast side of cove, 

Isla San Pedro Nolasco, Coll. N. P. Yensen (NPY 740320-3, 

=JN-5214, US Alg. Coll. microscope slide 4564).

Peyssonnelia orientalis (Figure 187C): Punta Palmilla, Baja 

California Sur, Coll. E. Y. Dawson (EYD-3245, AHFH, 

now UC). 

Gracilaria ascidiicola (Figure 188): 3.6–7.3 m depths, innermost bay, Puerto Escondido, Baja California Sur, Coll. E. Y. 

Dawson (EYD-7149: A, US Alg. Coll.-5690; B, isotype: US 

Alg. Coll.-41708).
NUMBER 96 • 493

Gracilaria crispata (Figure 189A): Intertidal rock platform with 

sand areas, Playa Hermosa, Puerto Peñasco, Sonora, Coll. 

J. N. Norris and K. E. Bucher (JN-3258, US Alg. Coll.-

159559). 

Gracilaria crispata (Figure 189B): Intertidal rock platform, 

Playa Las Conchas (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN-5866, US Alg. 

Coll.-159568).

Gracilaria crispata (Figure 190A–D): On cobbles, rocky intertidal shore on south side of bay, Bahía Bocochibampo, Sonora (EYD-1713 (♀), AHFH, now UC).

Gracilaria rubrimembra (Figure 190E–G): Intertidal, on flat, 

igneous reef with tide pools, south side of bay (near entrance 

to Puerto San Carlos), Ensenada de San Francisco, Sonora 

(E, holotype: EYD-1918 (♀), AHFH-4522, now UC; F, G, 

isotypes: EYD-1918, AHFH, now UC.

Gracilaria veleroae (Figure 190H): Netted in fish seine, shallow 

water of innermost bay (locally known as “Bahía Santa 

Lucia”) near center of town, Acapulco, Guerrero, Pacific 

Mexico (EYD-3916 (♂), AHFH, now UC).

Gracilaria pachydermatica (Figure 191A): Growing on granite rock, mid to low intertidal tide pools, Punta Pelícano, 

Sonora, Coll. J. N. Norris (JN-3953, US Alg. Coll.-159595).

Gracilaria pachydermatica (Figure 191B): On upper intertidal 

rocks, Isla Tortuga (northeast of Puerto Santa Rosalía), off 

Baja California Sur, Coll. I. M. Johnston (I.M.Johnston-122,

holotype: CAS-1355, now UC).

Gracilaria pachydermatica (Figure 191C): Intertidal, rocky 

shore, south side of bay Ensenada de San Francisco, near 

Guaymas, Sonora, Coll. E. Y. Dawson (EYD-1822 (♂),

AHFH, now UC).

Gracilaria pachydermatica (Figure 191D): Bahía Carrizal, near 

Cabo Arco (vicinity of Guaymas), Sonora, Coll. E. Y. Dawson (EYD-1682 (♀), AHFH, now UC).

Gracilaria pachydermatica (Figure 191E): On flat igneous reef 

with tide pools, south side of bay, Ensenada de San Francisco (near entrance to Puerto San Carlos), Sonora, Coll. 

E. Y. Dawson (EYD-1909, AHFH, now UC).

Gracilaria pinnata (Figure 192): 6–9 m depths, northwest of 

rock window on shore, Puerto Refugio, Isla Ángel de la 

Guarda, Coll. J. N. Norris and K. E. Bucher (JN-5334, US 

Alg. Coll.-159632). 

Gracilaria ramisecunda (Figure 193): Type collection (♀, ♂, 

and tetrasporophyte), in low intertidal tide pools on granitic reef, Cabeza Ballena (headland ~8 km east of Cabo San 

Lucas), Baja California Sur, Coll. E. Y. Dawson (holotype: 

EYD-3314, AHFH-12870, now UC).

Gracilaria rubrimembra (Figure 194): 6 m depth, Punta La 

Gringa, Bahía de Los Ángeles, Baja California, Coll. J. N. 

Norris and G. Boehlert (JN-3032: A, US Alg. Coll.-159638; 

B, US Alg. Coll.-159637).

Gracilaria spinigera (Figure 195): Drift along shore Ensenada 

de San Francisco, near Bahía San Carlos, Sonora, Coll. E. Y. 

Dawson (EYD-10986, US Alg. Coll.-7536). 

Gracilaria spinigera (Figure 196A): Ensenada de San Francisco 

(between Bahía San Carlos and Guaymas), Sonora, Coll. 

E. Y. Dawson (EYD-574-40, AHFH, now UC). 

Gracilaria spinigera (Figure 196B, D, E): Near Guaymas (EYD1659, AHFH, now UC). 

Gracilaria spinigera (Figure 196C): From type collection, Ensenada de San Francisco (between Bahía San Carlos and 

Guaymas), Sonora, Coll. E. Y. Dawson (holotype: EYD1903 (♂); AHFH-4949, now UC).

Gracilaria subsecundata (Figure 197A, B): Sand-mud tidal 

flats, 1.8–3.0 m depths on rock reef, Bahía La Choya 

(Bahía Cholla), vicinity of Puerto Peñasco, Sonora, Coll. 

J. N. Norris and K. E. Bucher (JN-4990, US Alg. Coll.-

159647).

Gracilaria veleroae (Figure 197C): Dredged 4.0–30 m, off Isla 

Tiburón, near Isla Turner, Coll. E. Y. Dawson (holotype: 

EYD-141a-40, AHFH-37, now UC).

Gracilaria tepocensis (Figure 198A): 4.5–9.5 m depths, dive off 

small islet, Puerto Refugio, Isla Ángel de la Guarda, Coll. 

J. N. Norris and K. E. Bucher (JN-5356, US Alg. Coll.-

156380). 

Gracilaria turgida (Figure 198B): In shallow tidal channels near 

mouth of mangrove estuary, Estero de Bahía de Las Ánimas, 

Coll. J. N. Norris (JN-3212, US Alg. Coll.-159687).

Gracilaria vivesii (Figure 199A): Dive 9.0–23 m depths, off west 

side of Roca Blanca, Puerto Refugio, Isla Ángel de la Guarda, 

Coll. J. N. Norris (JN-5252, US Alg. Coll.-159675). 

Gracilaria vivesii (Figure 199B): Dive 15–23 m depths, north 

of Punta La Gringa, Bahía de Los Ángeles, Baja California, 

Coll. F. Aguilar (JN-2966, US Alg. Coll.-159659). 

Gracilaria vivesii (Figure 199C): Intertidal to 7.6 m depth, 

Puerto Refugio, shore on NE end of Isla Ángel de la Guarda, 

Islas de la Cintura, Coll. J. N. Norris and K. E. Bucher (JN6198, US Alg. Coll.-159683).

Gracilariopsis animasensis, sp. nov. (Figure 200A): About 0.3 

m depth, in shallow tidal channel near mouth of mangrove 

estuary, Estero de Bahía de Las Ánimas, Coll. J. N. Norris and K. E. Bucher (holotype: JN-3215, US Alg. Coll.-

89276).

Gracilariopsis animasensis, sp. nov. (Figure 200B–D): Ensenada 

San Francisco (between Bahía San Carlos and Guaymas), 

Sonora (B, EYD-1814, AD-A6283; C, AD microscope slide 

21062; D, AD microscope slide 21061).
494 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Gracilariopsis animasensis, sp. nov. (Figure 201): Lake Butler, 

Robe, South Australia, Coll. H. B. S. Womersley (A, B, ADA64282c; C, AD-A63430, AD microscope slide 14314).

Gracilariopsis animasensis, sp. nov. (Figure 202): Lake Butler, 

Robe, South Australia, Coll. H. B. S. Womersley (A, ADA63430, AD microscope slide 14316; B, C, AD-A63430, 

microscope slide 14317; D, AD-A63430, microscope slide 

14320; E, AD-A63430, microscope slide 14319).

Cryptonemia angustata (Figure 203): Subtidal, Islas de Los 

Gemelos, Bahía de Los Ángeles, Baja California, Coll. 

H. Sleeper and M. Helvey (JN-4500, US Alg. Coll.-158994).

Cryptonemia guaymasensis (Figure 204A, B): Rocky shore 

fronting Laboratorio de Biología Marina, Playa Las Conches 

(Playa Estación), Punta Peñasco, Sonora, Coll. A. E. Dennis 

(EYD-27492, US Alg. Coll.-40772).

Cryptonemia opuntioides (Figure 204C): Dredged 12–16 m 

depths, off Isla Salsipuedes (Islas de San Lorenzo), Islas de 

la Cintura, Baja California (holotype: EYD-26126, US Alg. 

Coll. microscope slide 786). 

Cryptonemia obovata (Figure 205A): About 13.7 m depth, 

muddy bottom, attached to seashells, Canal de Infiernillo, 

midway between Isla Tiburón and west of Campo Viboras, 

Sonora, Coll. G. L. Kooyman and E. Senate (JN-4729, US 

Alg. Coll.-158996).

Cryptonemia obovata (Figure 205B): Dredged 9–36 m depths, 

Isla San Esteban, Coll. L. Pinkas, E. Smith, and D. Miller 

(California Department of Fish and Game; M/V Alaska expedition) (EYD-21577, US Alg. Coll.-7069). 

Grateloupia catenata (Figure 206): Puerto Lobos, Sonora, Coll. 

J. N. Norris and M. Helvey (JN-6058: A, US Alg. Coll.-

159869; B, US Alg. Coll. microscope slide 8684).

Grateloupia hancockii (Figure 207A): Intertidal, south end of 

Isla Estanque, Coll. J. N. Norris and K. E. Bucher (JN-5597, 

US Alg. Coll.-159781). 

Grateloupia hancockii (Figure 207B): On rocks in mud-sand flats, 

Bahía La Choya (Bahía Cholla), vicinity of Puerto Peñasco, 

Sonora, Coll. R. B. Searles (JN-5894, US Alg. Coll.-159782).

Grateloupia howei (Figure 208A): 4.6 m depth, southeast side 

of Isla San Esteban, Coll. K. E. Bucher (JN-5519, US Alg. 

Coll.-159785).

Grateloupia howei (Figure 208B): Low intertidal, rock outcropping cobblestone beach, NW side of Punta Robinson (Cabo 

Lobos), Puerto Libertad, Sonora, Coll. J. N. Norris (JN5920. US Alg. Coll.-159790). 

Grateloupia prolongata (Figure 209A): Beach drift, Desemboque de San Ignacio, Sonora, Coll. R. E. Schultes, R. S. 

Felger, and A. T. Weil (JN-5167, US Alg. Coll.-159794).

Grateloupia prolongata (Figure 209B): Off sand islet, 4.5–10.6 

m depths, Puerto Refugio, Isla Ángel de la Guarda, Coll. 

J. N. Norris (JN-5351, US Alg. Coll.-159796).

Grateloupia prolongata (Figure 209C): Dive to 4.6–6 m depths, 

rock outcropping, north side of point, Punta Lobos (vicinity 

of Puerto Lobos), Sonora, Coll. J. N. Norris (JN-5898, US 

Alg. Coll.-159804).

Grateloupia versicolor (Figure 210): 3.0–7.6 m depths, off 

southeast side of Isla San Esteban, Coll. J. N. Norris (JN5720, US Alg. Coll.-159814).

Grateloupia violacea (Figure 211): 2.4–6 m depths, Punta La 

Gringa, Bahía de Los Ángeles, Baja California, Coll. J. N. 

Norris, M. H. Hommersand, M. Yoshizaki, and G. Boehlert 

(A, JN-3053, US Alg. Coll.-159831; B, JN-3053-III, US 

Alg. Coll. microscope slide 4332; C, JN-3053-IX, US Alg. 

Coll. microscope slide 4521). 

Halymenia actinophysa (Figure 212A): Beach drift, Desemboque de San Ignacio, Sonora, Coll. R. E. Schultes, R. S. 

Felger, and A. T. Weil (JN-5137, US Alg. Coll.-159936). 

Halymenia actinophysa (Figure 212B–D): Subtidal, Islas de 

Los Gemelos, Bahía de Los Ángeles, Baja California, Coll. 

H. Sleeper and M. Helvey (JN-4501c, US Alg. Coll. microscope slide 4399).

Halymenia megaspora (Figure 213): Dredged 7.3–18.2 m [4–10 

fathoms], from bottom of free-living rhodoliths (species of 

Lithothamnion), about mid channel, Canal de San Lorenzo, 

between Isla Espíritu Santo and Gulf coast of Baja California Sur, Coll. E. Y. Dawson (EYD-6904A; paratype: US Alg. 

Coll.-206130).

Prionitis abbreviata var. abbreviata (Figure 214A): 3–5 m 

depths, dive off Campo Dolar, Cabo Tepopa, Sonora, Coll. 

J. N. Norris, D. P. Cheney, and C. J. Dawes (JN-7059, US 

Alg. Coll.-160707). 

Prionitis acroidalea (Figure 214B): Lower littoral, rocky reef at 

Bahía Agua Dulce, Isla Tiburón, Coll. E. Y. Dawson (EYD961, US Alg. Coll.-12842). 

Prionitis abbreviata var. guaymasensis (Figure 214C): Rocky 

shore in front of Laboratorio de Biología Marina, Playa Las 

Conches (Playa Estación), Puerto Peñasco, Sonora, Coll. 

E. Y. Dawson (EYD-27341, US Alg. Coll.-40742). 

Prionitis abbreviata var. guaymasensis (Figure 214D): Mid intertidal, Cumpleaños Tide Pool, Playa Las Conches (Playa 

Estación), Puerto Peñasco, Sonora, Coll. K. E. Bucher (JN4051, US Alg. Coll.-160679). 

Tsengia abbottiana (Figure 215): 15–23 m depths, on rock-shell bottom, dive off southeast end of Isla Mejía, in narrow channel 

between Isla Mejía and Isla Ángel de la Guarda, Coll. J. N. Norris (JN-5677: A, holotype: US Alg. Coll.-55677; B, C, squash 

preparation of type, US Alg. Coll. microscope slide 1071).
NUMBER 96 • 495

Predaea japonica (Figure 217A): 9 m depth, off NW side of the 

rock window on shore, Puerto Refugio, Isla Ángel de la 

Guarda, Coll. J. N. Norris and K. E. Bucher (JN-5300; US 

Alg. Coll.-160633). 

Predaea japonica (Figure 217B): Subtidal, Isla Estanque, Coll. 

J. N. Norris and K. Bucher, s.n. (US Alg. Coll. microscope 

slide 5296). 

Predaea japonica (Figure 217C): Dive 23 m depth, off west side 

of Roca Blanca, Puerto Refugio, Isla Ángel de la Guarda, 

Coll. J. N. Norris (JN-5295, US Alg. Coll. microscope slide 

5298).

Schizymenia pacifica (Figure 218A): Intertidal, NE side, rocky 

shoreline, Puerto Refugio, Isla Ángel de la Guarda, Coll. 

J. N. Norris (JN-5759, US Alg. Coll.-160898). 

Schizymenia pacifica (Figure 218B, C): Intertidal, rocky shoreline, 

northeast end of Puerto Refugio, Isla Ángel de la Guarda, Coll. 

K. Bucher (B, JN-5747c, US Alg. Coll. microscope slide 4524; 

C, JN-5747, US Alg. Coll. microscope slide 4526).

Plocamium katinae, sp. nov. (Figure 219A): Intertidal rock platform and Cumpleaños Tide Pool, Playa Las Conches (Playa 

Estación), Puerto Peñasco, Coll. J. N. Norris and K. E. Bucher (holotype: JN-3632a, US Alg. Coll.-160510).

Plocamium katinae, sp. nov. (Figure 219B): Intertidal rock platform and Cumpleaños Tide Pool, Playa Las Conches (Playa 

Estación), Puerto Peñasco, Coll. J. N. Norris and W. Fenical 

(JN-4163, US Alg. Coll.-217348).

Plocamium katinae, sp. nov. (Figure 219C): 4.6–6.0 m depths, 

off north side of point, Punta Lobos (vicinity of Puerto 

Lobos), Sonora, Coll. J. N. Norris (JN-5916, US Alg. Coll.-

160531; left specimen, US Alg. Coll. microscope slide 8682, 

and right specimen, US Alg. Coll. microscope slide 8683).

Plocamium katinae, sp. nov. (Figure 219D, E): Dive 4.5–6 m 

depths, Punta Lobos, north side of point, Coll. J. N. Norris 

(JN-5916, US Alg. Coll. microscope slides 8682, 8683).

Sebdenia flabellata (Figure 220A): 10.1 m depth, dive off the 

south end of Isla Estanque, Islas de la Cintura, Coll. J. N. 

Norris and K. E. Bucher (JN-5490; US Alg. Coll.-217352).

Sebdenia flabellata (Figure 220B): 7.6–18 m depth, rocky substrate, Isla la Ventana, Bahía de Los Ángeles, Baja California, 

Coll. J. N. Norris, M. Helvey, and H. Sleeper (JN-4430, US 

Alg. Coll. microscope slide 4503).

Sebdenia flabellata (Figure 220C): On rocks, 9 m depth, Caleta 

Santa María (north of Santa Rosalía), Baja California Sur, 

Coll. D. G. Lindquist (sta. no. DGL-720811-1) (JN-3398, 

US Alg. Coll. microscope slide 4501).

Champia disticha (Figure 221A): Epiphytic on Laurencia, mid 

intertidal, Isla San Esteban, Coll. E. Y. Dawson (holotype: 

EYD-441; AHFH-51, now UC).

Champia caespitosa (Figure 221B): Epiphytic on articulated coralline, mid intertidal, Isla Estanque (holotype: EYD-407-

40; AHFH-52, now UC).

Gastroclonium compressum (Figure 221C): Intertidal rock platform, Playa Las Conches (Playa Estación), Puerto Peñasco, 

Sonora, Coll. J. N. Norris (JN-5234, US Alg. Coll.-158972).

Champia cf. parvula (Figure 222A): Intertidal to 9 m depth, 

dive NW of the rock window on shore, Puerto Refugio, Isla 

Ángel de la Guarda, Coll. J. N. Norris and K. E. Bucher (JN5311, US Alg. Coll.-158921). 

Champia cf. parvula (Figure 222B–D): Intertidal rock platform, 

Playa Hermosa, (~0.4 km west of Playa Hermosa Hotel), 

vicinity of Puerto Peñasco, Sonora, Coll. J. N. Norris and 

K. E. Bucher (JN-4001, US Alg. Coll. microscope slide 

4583).

Gastroclonium pacificum (Figure 223): Rocky reefs with large 

tide pools, Ensenada de San Francisco, near Guaymas, 

Sonora, Coll. E. Y. Dawson (EYD-1808, US Alg. Coll.-

207564).

Gloiocladia hoshawii (Figure 224A): 15 m depth, Isla San Pedro 

Nolasco, near Guaymas, Sonora, Coll. R. W. Hoshaw and 

E. Y. Dawson, s.n. (holotype: US Alg. Coll.-40926). 

Gloiocladia hoshawii (Figure 224B–D): 21 m depth, Islas de Los 

Gemelos, Bahía de Los Ángeles, Baja California, Coll. J. N. 

Norris (JN-3008: B, US Alg. Coll.-159134; C, US Alg. Coll. 

microscope slide 4595; D, US Alg. Coll. microscope slide 

4596).

Gloiocladia mollis (Figure 225): 9–36 m depths, Isla San Esteban, Coll. L. Pinkas, E. Smith, and D. Miller (California 

Department of Fish and Game; M/V Alaska expedition) 

(EYD-21579, US Alg. Coll.-51351).

Gloiocladia sefferi (Figure 226A, C): Dive 3–15 m depths, off 

north end of Isla Coronado, Bahía de Los Ángeles, Baja 

California, Coll. H. Sleeper and M. Helvey (JN-4336: A, US 

Alg. Coll.-159135; C, US Alg. Coll. microscope slide 4233).

Gloiocladia sefferi (Figure 226B): 9–36 m depths, Isla San Esteban, Coll. L. Pinkas, E. Smith, and D. Miller (California 

Department of Fish and Game; M/V Alaska expedition) 

(EYD-21558, US Alg. Coll.-7202). 

Gloioderma conjuncta (Figure 227A): Bahía San Carlos, Sonora, 

Coll. D. E. Bean, s.n. (US Alg. Coll.-94253). 

Gloioderma conjuncta (Figure 227B): Dive 10 m depth, off west 

side of Roca Blanca, Puerto Refugio, Isla Ángel de la Guarda, 

Coll. J. N. Norris (JN-5276, US Alg. Coll.-159529).

Ceratodictyon variabile (Figure 228): Rocky intertidal (near 

transect line), Playa Las Conches (Playa Estación), Puerto 

Peñasco, Sonora, Coll. J. N. Norris (JN-6087, US Alg. Coll.-

159333).

Lomentaria catenata (Figure 229): On rocks, dive to 4.6–6 m 

depths, north side of point, Punta Lobos (vicinity of Puerto 
496 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Lobos), Sonora, Coll. J. N. Norris (JN-5899: A, US Alg. 

Coll.-160463; B, US Alg. Coll.-160462).

Lomentaria hakodatensis (Figure 230): On rocks, inner bay, 

Bahía de Topolobampo, Sinaloa, Coll. E. Y. Dawson (EYD10896, US Alg. Coll.-12228).

Botryocladia datilensis (Figure 231A): 15–24 m depths, rocky 

substrate, Isla la Ventana, Bahía de Los Ángeles, Baja California, Coll. J. N. Norris, M. Yoshizaki, G. Boehlert, and 

M. H. Hommersand (JN-2993, US Alg. Coll.-158661).

Botryocladia datilensis (Figure 231B–D): 7.6–24 m depths, 

rocky substrate, Isla la Ventana, Bahía de Los Ángeles, Baja 

California, Coll. J. N. Norris, M. Helvey, and H. Sleeper 

(JN-4429, US Alg. Coll. microscope slide 4589).

Botryocladia guaymasensis (Figure 232A): Rocky intertidal and 

Cumpleaños Tide Pool, Playa Las Conches (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris (JN-6083b, US 

Alg. Coll.-158697). 

Botryocladia guaymasensis (Figure 232B): Rocky intertidal, 

Playa Las Conches (Playa Estación), Puerto Peñasco, Sonora, Coll. J. N. Norris and K. E. Bucher (JN-5858, US Alg. 

Coll.-158696).

Botryocladia guaymasensis (Figure 232C): Rocky reef, off west 

side of sand-cobble beach, 1.5–4.6 m depths, Punta Robinson (~2.4 km east of Puerto Libertad), Sonora, Coll. J. N. 

Norris and K. E. Bucher (JN-4847, US Alg. Coll. microscope slide 4588).

Botryocladia uvarioides (Figure 233A): Mid intertidal rocks, 

west of Casa Garcia, Playa Las Conches (Playa Estación), 

Puerto Peñasco, Sonora, Coll. J. N. Norris and K. Bucher 

(JN-3145, US Alg. Coll.-217353). 

Botryocladia uvarioides (Figure 233B): Dredged 40 m depth, off 

San Jose del Cabo, Baja California Sur, Coll. J. T. Howell 

(syntypes: JTH-727 and JTH-598; CAS, now UC; and 

AHFH-49, now UC).

Irvinea hancockii (Figure 234): 10.6 m depth, south end of Isla 

Estanque, Coll. J. N. Norris and K. E. Bucher (JN-5600, US 

Alg. Coll.-217355).

Rhodymenia dawsonii (Figure 235A, B): 0.3–1.8 m depths, Isla 

Cholla, off Isla Carmen, Coll. E. Y. Dawson (EYD-18658, 

US Alg. Coll.-13019).

Rhodymenia divaricata (Figure 235C): On mud bottom, dredged 

from about 3.6–5.5 m, Bahía Guaymas, Sonora, Coll. E. Y. 

Dawson (holotype: EYD-53-40; AHFH-1, now UC).

Rhodymenia hancockii (Figure 236A): Intertidal rocks to 1.8 m 

depth, in front of Laboratorio de Biología Marina, Playa 

Las Conches (Playa Estación), Puerto Peñasco, Sonora, 

Coll. J. N. Norris (JN-2938, US Alg. Coll.-160805).

Rhodymenia hancockii (Figure 236B): 6 m depth, off west side 

of small cove Punta Cirio (south of Puerto Libertad), Sonora, Coll. J. N. Norris, K. E. Bucher, and D. Moore (JN4875, US Alg. Coll.-160814).
References

Abbott, I. A. 1945. The Genus Liagora (Rhodophyceae) in Hawaii. Occasional Papers of Bernice Bishop Museum

18(10): 145–169.

Abbott, I. A. 1947. Brackish-Water Algae from the Hawaiian Islands. Pacific Science 1: 193–214.

Abbott, I. A. 1962. Some Liagora-Inhabiting Species of Acrochaetium. Occasional Papers of Bernice Bishop Museum 23: 77–120. 

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Index of Scientific Names

Names of all taxa of marine red algae recognized in the northern Gulf of California 

are shown in bold type. All other taxa listed (non-bold) are either synonyms, have distribution that does not include the northern Gulf, or are otherwise discussed or mentioned 

in the text. Higher taxa (e.g., orders and families) are in Small capital letters. Genera 

and species are in italics. 

Page numbers in bold type refer to the start of the taxa descriptions. Numbers in 

italic type refer to pages with figures of the named taxa. All other page numbers refer to 

basionyms or synonyms or to discussion or mention of the taxa elsewhere in the text. 

Acrocarpus gracilis, 456

Acrochaetiaceae, 38, 39, 475, 477

Acrochaetiales, 38, 39, 74, 475, 477

Acrochaetium, 12, 38, 39, 40, 43, 60, 62, 68, 69, 429

Acrochaetium arcuatum, 40, 40

Acrochaetium bornetii, 39, 40, 41

Acrochaetium corymbiferum, 40

Acrochaetium crassipes, 40, 41, 41, 42, 480

Acrochaetium daviesii, 45

Acrochaetium desmarestiae, 48

Acrochaetium grateloupiae, 150

Acrochaetium hancockii, 45

Acrochaetium-like, 12, 38, 39, 60, 62, 68, 69, 429

Acrochaetium microscopicum, 39, 41, 42

Acrochaetium pacificum, 46, 47, 50

Acrochaetium pectinatum, 44

Acrochaetium porphyrae, 39, 40, 42, 43

Acrochaetium plumosum, 47

Acrochaetium punctatum, 46, 47, 48

Acrochaetium savianum, 41, 48

Acrochaetium scinaiae, 46, 47, 48

Acrochaetium secundatum, 39, 40, 43, 480

Acrochaetium seriaspora, 39, 40, 43, 475, 477, 480

Acrochaetium sinicolum, 49

Acrochaetium subimmersum, 75, 76

Acrochaetium tenuissimum, 49

Acrochaetium variabile, 47, 50

Acrochaetium virgatulum f. tenuissimum, 49

Acropeltis, 305
544 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Acrosymphyton, 

Acrosymphyton caribaeum, 

147

Adelophycus, 429

Aeodes, 

Aeodes gardneri, 364, 421

Agardhiella, 188, 353, 354, 396

Agardhiella coulteri, 353, 358

Agardhiella gaudichaudii, 358

Agardhiella mexicana, 353,

354, 358, 478

Agardhiella subulata, 353, 358

Agardhiella tenera, 353, 358

Aglaophenia, 48

Aglaothamnion, 150

Aglaothamnion endovagum, 

150, 151

Ahnfeltia, 141

Ahnfeltia gigartinoides, 114

Ahnfeltia plicata, 141

Ahnfeltia svensonii, 141,

142, 483

Ahnfeltiaceae, 141

Ahnfeltiales, 141

Ahnfeltiophycidae, 34, 141

Ahnfeltiopsis, 346

Ahnfeltiopsis divaricata, 346,

347, 350

Ahnfeltiopsis gigartinoides, 

114

Ahnfeltiopsis hancockii, 346, 

347, 347, 348, 475, 491

Ahnfeltiopsis leptophylla, 

346, 348

Ahnfeltiopsis serenei, 346, 

348, 348, 349, 492

Alysium, 52

Amphiroa, 15, 21, 77, 79, 84, 

92, 93, 98, 101, 132, 133, 

188, 190, 192, 248, 270, 

443, 444, 484

Amphiroa annulata, 98, 99, 

100

Amphiroa annulata var. 

pinnata, 100

Amphiroa beauvoisii, 93, 94,

95, 97, 100, 481

Amphiroa brevianceps, 93, 

95, 96, 98

Amphiroa compressa, 93

Amphiroa compressa var. 

tenuis, 93

Amphiroa crosslandii, 94

Amphiroa currae, 93

Amphiroa dimorpha, 97

Amphiroa dimorpha var. 

digitiformis, 97

Amphiroa drouetii, 94, 95

Amphiroa foliacea, 93

Amphiroa franciscana, 95

Amphiroa franciscana var. 

robusta, 94

Amphiroa linearis, 94

Amphiroa magdalenensis, 

93, 96

Amphiroa mexicana, 93, 

96, 97

Amphiroa misakiensis, 93, 

96, 97, 97, 482

Amphiroa peninsularis, 94, 96

Amphiroa polymorpha, 93

Amphiroa pusilla, 94, 97

Amphiroa rigida, 94, 98, 99, 

100

Amphiroa rigida var. 

antillana, 98

Amphiroa sect. 

Chielosporum, 84

Amphiroa subcylindrica, 100, 

101, 482

Amphiroa taylorii, 94, 98, 99

Amphiroa valonioides, 93, 

98, 99, 99, 100, 482

Amphiroa vanbosseae, 93, 

100, 101, 482

Amphiroa zonata, 94, 95, 97

Amplisiphonia, 238, 284, 285

Amplisiphonia? pacifica, 

285, 285, 286, 490

Anatheca, 

Anatheca dichotoma, 354

Anatheca elongata, 358

Anatheca furcata, 354

Anisocladella, 

Anisocladella pacifica, 222

Anotrichium, 16, 21, 291, 295

Anotrichium anthericephalum, 292

Anotrichium furcellatum, 

292, 293, 490

Anotrichium multiramosum, 

292, 293

Anotrichium multiramosum 

var. minor, 293

Anotrichium secundum, 16, 

291, 293, 294, 295, 479, 

490

Anotrichium tenue, 293, 294, 

295

Anotrichium tenue var. 

secundatum, 293

Anotrichium tenue var. 

thyrsigerum, 294

Antithamnion, 157, 158

Antithamnion antillanum, 

158

Antithamnion breviramosus, 

163

Antithamnion crouanioides, 

167

Antithamnion decipiens, 158,

159, 484

Antithamnion defectum, 158, 

159, 160, 161, 484

Antithamnion dendroideum, 

160

Antithamnion densum, 161

Antithamnion elegans, 163

Antithamnion fragilissimum, 

158

Antithamnion floccosum 

f. pacificum, 167

Antithamnion gardneri, 165

Antithamnion glanduliferum, 

165, 166

Antithamnion hubbsii, 158

Antithamnion kylinii, 158, 

161, 162, 484

Antithamnion lherminieri, 158

Antithamnion mcnabbii, 155, 

157, 158

Antithamnion miharae, 165

Antithamnion nematocladellum, 161

Antithamnion ogdeniae, 158

Antithamnion orbignianum, 

201

Antithamnion pacificum, 167

Antithamnion plumulum var. 

plumulum, 158

Antithamnion pseudocorticatum, 158, 167

Antithamnion pygmaeum, 159

Antithamnion secundatum, 

159, 161

Antithamnion setaceum, 159

Antithamnion sparsum, 161

Antithamnion spirographidis, 

165

Antithamnion sublittorale, 166

Antithamnion tenuissimum, 

165

Antithamnion veleroae, 166

Antithamnionella, 157, 161, 

163, 165, 166

Antithamnionella breviramosa, 163, 164, 165, 484

Antithamnionella elegans, 163

Antithamnionella glandulifera, 165

Antithamnionella latiaxis, 155

Antithamnionella miharae, 

165

Antithamnionella mcnabbii, 

155, 157

Antithamnionella pacifica, 

167

Antithamnionella cf. 

spirographidis, 163, 165, 

165, 166, 484

Antithamnionella spirographidis, 165, 166

Antithamnionella sublittoralis, 163, 166

Antithamnionella ternifolia, 

166

Apiarium, 219

Apoglossum, 214, 215

Apoglossum gregarium, 215,

215, 216, 487

Apoglossum punctatum, 222, 

223, 487

Apophlaea, 35

Archaeplastida, 12, 13

Ascomycota, 35

Asparagopsis, 28, 39, 42, 43, 

143, 144, 146, 480

Asparagopsis armata, 145, 

146

Asparagopsis delilei, 144

Asparagopsis hamifera, 147

Asparagopsis sanfordiana, 

144, 145, 146

Asparagopsis sanfordiana f. 

amplissima, 144, 145, 146

Asparagopsis taxiformis, 43, 

143, 144, 145, 146, 483

Falkenbergia hillebrandiiphase of, 146, 483

Falkenbergia-phase of, 143, 

144, 146, 146, 484

Asterocytis, 14

Asterocytis ornata, 14

Asterocytis ramosa, 14

Audouinella, 39, 43, 47, 50

Audouinella arcuata, 40

Audouinella crassipes, 41, 42

Audouinella daviesii, 45

Audouinella microscopica, 42

Audouinella pacifica, 47

Audouinella plumosa var. 

variabilis, 50

Audouinella porphyrae, 42

Audouinella saviana, 48

Audouinella secundata, 43

Audouinella seriaspora, 43

Audouinella subimmersa, 75

Audouinella tenuissima, 49

Audouinella variabilis, 50

Bakothamnion, 

Bakothamnion curassavicum, 

167, 168

Balliales, 37 

Balliella, 157, 167

Balliella crouanioides, 167

Balliella pseudocorticata, 

158, 167, 168

Bangia, 12, 26, 27, 28, 29, 

33, 34

Bangia alsidii, 15

Bangia atropurpurea, 28, 29

Bangia ciliaris, 19, 24

Bangia elegans, 15

Bangia enteromorphoides, 

27, 28, 480

Bangia fuscopurpurea, 28, 29

Bangia-like, 29

Bangia maxima, 29

Bangia-phase, 27

Bangia vermicularis?, 27, 28, 

29, 480

Conchocelis-phase of, 26, 

27, 33

Bangiaceae, 26, 27, 477

Bangiadulcis, 28, 29

Bangiadulcis atropurpurea, 

28, 29

Bangiales, 26, 27, 477

Bangiomorpha, 12
NUMBER 96 • 545

Bangiophyceae, 12, 13, 25, 

26, 34

Bangiophycidae, 12, 26

Beringia, 342

Betaphycus, 361

Binghamia, 457

Binghamiopsis, 457

Blidinga minima var. vexata, 35

Boergeseniella, 282

Bonnemaisonia, 143, 146, 147

Bonnemaisonia asparagopsis, 

147

Bonnemaisonia californica, 

147

Bonnemaisonia clavata, 147

Bonnemaisonia geniculata, 

147

Bonnemaisonia hamifera, 

143, 147, 148, 483, 484

Bonnemaisonia intricata, 147

Bonnemaisonia nootkana, 147

Bonnemaisoniaceae, 143

Bonnemaisoniales, 142, 143

Boreophyllum, 30

Bossiella, 79, 492

Bossiella californica, 80

Bossiella frondescens, 83

Bossiella orbigniana, 79

Bostrychia, 219, 238, 239, 240

Bostrychia moritziana, 239, 

240

Bostrychia radicans, 239, 240

Bostrychia radicans f. moniliforme, 239

Bostrychia rivularis, 240

Botryocladia, 15, 21, 460, 461,

462, 465, 486

Botryocladia adhaerens, 461

Botryocladia ardreana, 465

Botryocladia chiajeana, 461

Botryocladia datilensis, ii, 

461, 462, 462, 476, 478, 

496

Botryocladia guaymasensis, 

461, 462, 463, 478, 496

Botryocladia hancockii, 465

Botryocladia occidentalis, 461

Botryocladia pseudodichotoma, 462, 463, 464

Botryocladia pseudodichotoma var. datilensis, 462, 

463

Botryocladia uvarioides, 461, 

462, 463, 464, 496

Branchioglossum, 15, 214, 216

Branchioglossum battstroemii, 

218

Branchioglossum bipinnatifidum, 216, 217, 218, 487

Branchioglossum macdougalii, 

218

Branchioglossum undulatum, 

216, 218, 219, 487

Branchioglossum woodii, 

216, 218

Bryocladia,

Bryocladia dictyurus, 284

Bryopsis, 15, 48

Callithamniaceae, 149, 150, 

477

Callithamniaceae tribus

­Callithamnieae, 150

Callithamniaceae tribus

Crouanieae, 153

Callithamnion, 150, 151, 485

Callithamnion bisporum var. 

australe, 151, 152, 477, 

484

Callithamnion bisporum var. 

bisporum, 151

Callithamnion breviramosum, 

153

Callithamnion crispellum, 

212

Callithamnion daviesii, 45

Callithamnion daviesii var. 

secundatum, 43

Callithamnion decipiens, 158

Callithamnion densum, 161

Callithamnion endovagum, 

150

Callithamnion fragilissimum, 

158

Callithamnion floccosum var. 

pacificum, 166

Callithamnion marshallense, 

151, 152

Callithamnion microscopicum, 42

Callithamnion orbignianum, 

201

Callithamnion paschale, 151, 

152

Callithamnion ramosissimum, 151, 152, 153

Callithamnion rigidum, 153

Callithamnion rupicola, 151, 

153, 302

Callithamnion savianum, 48

Callithamnion secundatum, 43

Callithamnion sp., 150 

Callithamnion squarrulosum,

300

Callithamnion thyrsigerum, 

294

Callithamnion uncinatum, 

153, 302

Callithamnion vancouverianum, 303

Callithamnion varispiralis, 

153

Callithamnion veleroae, 152

Callophyllis, 

Callophyllis johnstonii, 347, 

350

Callophyllis violacea, 344

Callymenia, 

Callymenia angustata, 406

Callymenia guaymasensis, 408

Callymenia oblongifructa, 

345

Callymenia veleroae, 410

Caloglossa, 214, 218, 219, 220, 

473

Caloglossa apomeiotica, 220, 

220, 221, 487

Caloglossa leprieurii, 220, 

221

Caloglossa leprieurii?, 220, 

221

Calosiphonia, 

Calosiphonia caribaeum, 147

Caretta caretta, 264

Carpopeltis, 

Carpopeltis cornea, 425

Carradoria, 262

Carradoriella, 262

Carradoriella virgata, 262

Catenella, 219

Caulacanthaceae, 319

Caulacanthus, 319, 320

Caulacanthus indicus, 320

Caulacanthus okamurae, 320

Caulacanthus sp., 320

Caulacanthus ustulatus, 320

Centroceras, 157, 168, 169, 

176, 193, 194, 195, 443

Centroceras bellum, 194, 195

Centroceras clavulatum, 168,

169, 171

Centroceras clavulatum var. 

inerme, 169

Centroceras gasparrinii, 168, 

169, 170, 171, 484

Centroceras inerme, 169

Ceramiaceae, 149, 157, 288, 478

Ceramiaceae tribus Antithamnieae, 158

Ceramiaceae tribus Ceramieae, 

168

Ceramiaceae tribus Delesseriopseae, 167

Ceramiaceae tribus Dohrnielleae, 161, 166

Ceramiaceae tribus Pterothamnieae, 199

Ceramiaceae tribus Spermothamnieae, 296

Ceramiales, 34, 142, 149, 471, 

477, 473, 475, 476, 477, 

478

Ceramiella, 

Ceramiella bella, 194

Ceramiella procumbens, 189

Ceramithamnion, 

Ceramithamnion codii, 191

Ceramium, 157, 171, 177, 182, 

186, 188, 290

Ceramium aciculare, 329

Ceramium aduncum, 172, 

173, 173, 174, 177, 178, 

484, 485

Ceramium affine var. affine,

172, 174, 175, 484

Ceramium affine var. 

originale, 174

Ceramium affine var. peninsularis, 174, 175, 484

Ceramium avalonae, 176, 178

Ceramium bicorne, 191

Ceramium camouii, 172, 175

Ceramium caudatum, 49, 

172, 176, 176, 177, 178, 

485

Ceramium clarionense, 173, 

174, 177, 178, 485

Ceramium clarionensis, 178

Ceramium clavulatum, 168

Ceramium clavulatum var. 

inerme, 169

Ceramium codicola, 172, 

178, 179, 184

Ceramium codii, 171, 191

Ceramium codiophilum, 178

Ceramium daviesii, 45

Ceramium dawsonii, 198

Ceramium equisetoides, 172, 

179, 180, 181, 485

Ceramium fastigiatum var. 

pubescens, 184

Ceramium fimbriatum, 195

Ceramium flaccidum, 198

Ceramium gasparrinii, 169

Ceramium giacconei, 171

Ceramium gracillimum var. 

byssoideum, 196, 198

Ceramium hamatispinum, 

172, 179, 180, 181, 485

Ceramium horridulum, 172, 

179, 181, 182, 186, 485

Ceramium horridum, 179

Ceramium howellii, 172, 

182, 182, 183, 485

Ceramium interruptum, 171, 

183, 183, 184, 192, 485

Ceramium johnstonii, 192

Ceramium macilentum, 184, 

185

Ceramium masonii, 198

Ceramium mazatlanense, 

172, 184, 185, 485

Ceramium monacanthum, 171

Ceramium mucronatum, 171

Ceramium obesum, 171, 172, 

185, 186, 478, 485

Ceramium pacificum, 172, 

179, 182, 185, 186

Ceramium paniculatum, 172, 

187, 187, 188, 485

Ceramium pennatum, 280

Ceramium periconicum, 171, 

172, 188, 189, 478, 485

Ceramium personatum, 171

Ceramium procumbens, 172, 

189, 190, 485

Ceramium recticorticum, 198, 

199

Ceramium rubrum var. 

pacificum, 185
546 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Ceramium (continued)

Ceramium secundatum, 43

Ceramium serpens, 186, 172, 

190, 191, 485

Ceramium sertularioides, 266

Ceramium sinicola var. 

interruptum, 183, 184, 

192

Ceramium sinicola var. johnstonii, 172, 192, 478

Ceramium sinicola var. sinicola, 171, 178, 182, 184, 

191, 191, 192, 485

Ceramium sp., 179, 192

Ceramium sp. nov.?, 173

Ceramium taylorii, 199

Ceramium vagabundum, 192

Ceramium vagans, 172, 192,

193

Ceramium washingtoniense, 

186

Ceramium zacae, 172, 193

Ceratodictyon, 304, 376, 455

Ceratodictyon spongiosum, 

457

Ceratodictyon tenuis, 304, 

455, 456, 457, 476

Ceratodictyon variabile, 371, 

455, 456, 456, 457, 495

Chaetangiaceae, 51

Chaetomorpha, 19, 21, 22, 25, 

42, 48, 139, 199

Champia, 442, 443, 444, 445, 

447, 473

Champia caespitosa, 443, 

444, 445, 495

Champia disticha, 443, 444,

444, 445, 478, 495

Champia cf. parvula, 443,

445, 446, 495

Champia parvula, 443, 444, 

445

Champia vieillardii, 445

Champiaceae, 442, 478

Chantransia, 38

Chantransia corymbifera, 40

Chantransia crassipes, 41

Chantransia daviesii, 45

Chantransia microscopica, 42

Chantransia pacifica, 47

Chantransia saviana, 48

Chantransia secundata, 43

Chantransia tenuissima, 49

Chantransia virgatula f. 

tenuissima, 49

Chantransiaceae, 38

Cheilosporum, 84, 85, 132

Chelonia mydas agassizii, 165, 

264

Chondracanthus, 9, 329, 415

Chondracanthus acicularis, 

329, 330, 491

Chondracanthus canaliculatus, 334

Chondracanthus chauvinii, 331

Chondracanthus intermedius,

329, 330, 334

Chondracanthus johnstonii, 

329, 331

Chondracanthus macdougalii, 

329, 331

Chondranthus okamurae, 

330, 331, 334

Chondracanthus pectinatus, 

331, 333

Chondracanthus squarrulosus, 9, 329, 331, 332, 333, 

478, 491

Chondracanthus teedei, 333

Chondracanthus tenellus, 330

Chondracanthus tepidus, 

329, 333, 333, 491

Chondracanthus zertuchei, 

329, 330, 331, 333, 334, 

475, 478, 491

Chondria, 239, 240, 242

Chondria acrorhizophora, 

240, 241, 241, 242, 488

Chondria arcuata, 240

Chondria californica, 241, 

242

Chondria californica f. 

concrescens, 242

Chondria californica f. 

cuscutoides, 242, 242

Chondria clarionensis, 241, 

242

Chondria concrescens, 242

Chondria cuscutoides, 242

Chondria dasyphylla, 242, 

242, 243

Chondria decipiens, 480

Chondria furcata, 449

Chondria glandulifera, 255

Chondria obtusa var. paniculata, 255, 259

Chondria oppositiclada, 252, 

253

Chondria pacifica, 243

Chondria parvula, 445

Chondria pellucida, 243

Chondria repens, 240, 242

Chondria species A, 240, 

242, 242, 243, 478

Chondria telmoensis, 243

Chondria tenuissima f. 

californica, 241

Chondrophycus, 239, 249, 255

Chondrophycus glanduliferus, 

255, 261

Chondrophycus paniculatus, 

259, 260

Chondrophycus subgen. 

Chondrophycus, 249

Chondrophycus subgen. 

Kangjaewonia, 249

Chondrophycus subgen. 

Palisada, 258

Chondrophycus subgen. 

Yuzurua, 249

Chondrophycus thuyoides, 

260

Chondrosiphonaceae, 453

Chondrothamnion, 457

Chondrus, 

Chondrus affinis, 336, 337

Choreocolacaceae, 404

Choreonema, 78, 132

Choreonema thuretii, 132

Chromastrum, 

Chromastrum arcuatum, 40

Chromastrum crassipes, 41

Chromastrum microscopicum, 42

Chromastrum porphyrae, 42

Chromastrum secundatum, 43

Chromastrum seriasporum, 43

Chromastrum tenuissimum, 49

Chroodactylon, 14

Chroodactylon ornatum, 14

Chroodactylon ramosum, 14

Chrootheceaceae, 13

Chrootheceales, 13

Chrysymenia, 461

Chrysymenia chiajeana, 461

Chrysymenia pseudodichotoma, 463

Chrysymenia sect. Botryocladia, 461

Chylocladia, 447

Cladophora, 15, 16, 23, 25, 41, 

42, 479, 480

Cladophora vagabunda, 192

Clarionea, 430

Clarionea masonii, 432

Clymene, 27

Codium, 153, 172, 174, 177, 

178, 179, 184, 192, 268, 

270, 271, 298, 301

Codium fragile, 193

Codium simulans, 174, 485

Coeloseira, 445

Coeloseira compressa, 447

Coeloseira pacifica, 447, 448

Coeloseira parva, 448

Coelothrix, 457

Colaconema, 39, 44, 47

Colaconema daviesii, 44, 45

Colaconema desmarestiae, 49

Colaconema hancockii, 45,

46, 47, 476, 477, 480

Colaconema pacificum, 45, 

46, 47, 48, 50

Colaconema pectinatum, 44

Colaconema plumosum var. 

variabile, 50

Colaconema plumosum, 

47, 50

Colaconema porphyrae, 42

Colaconema punctatum, 43, 

44, 46, 47, 48, 476, 477, 

480

Colaconema savianum, 44, 48

Colaconema scinaiae, 44, 46, 

47, 48, 49, 476

“Colaconema secundata”, 43

Colaconema secundatum, 

43, 49

Colaconema sinicola, 44, 46, 

47, 49, 476, 480

Colaconema subimmersum, 75

Colaconema tenuissimum, 

43, 45, 46, 47, 49

Colaconema variabile, 45, 

46, 47, 48, 50, 476

Colaconemataceae, 38, 39, 44, 

476, 477

Colaconematales, 37, 38, 44,

476, 477

Colpomenia, 20

Colpomenia tuberculata, 8, 9, 

22, 479

Colpomenia phaeodactyla, 9

Compsopogonophyceae, 13, 

16, 17

Conchocelis, 33, 480

Conchocelis-like, 33

Conchocelis-phase, 26, 27, 

29, 30, 31, 33, 33, 34

Conchocelis-phase of Pyropia, 33, 33, 34, 480

Conchocelis rosea, 33

Conferva,

Conferva atropurpurea, 28

Conferva carnea, 21

Conferva ceramicola, 21

Conferva daviesii, 45

Conferva floridula, 75

Conferva griffithsiana, 290

Conferva ornata, 14

Conferva pennata, 280

Conferva simplex, 243

Conferva stricta, 274

Conferva urceolata, 274

Conferva vagabunda, 192

Corallina, 8, 9, 21, 77, 79, 80,

81, 82, 83, 85, 92, 93, 

114, 119, 120, 132, 133, 

188, 444, 482

Corallina aculeata, 84

Corallina adhaerens, 86

Corallina chilensis, 80

Corallina confusa, 84

Corallina cylindrica, 60

Corallina decussatodichotoma, 89

Corallina frondescens, 83

Corallina gracilis, 85

Corallina gracilis f. densa, 84

Corallina gracilis var. 

lycopodioides, 84

Corallina gracilis var.

verticillata, 85

Corallina gracilis var.

verticillatum, 85

“Corallina (Jania) tenella”, 91

Corallina lapidescens, 57

Corallina marginata, 53

Corallina membranacea, 139

Corallina oblongata, 62
NUMBER 96 • 547

Corallina officinalis f. robusta, 

81

Corallina officinalis var. 

chilensis, 80, 81, 481

Corallina pilifera, 121

Corallina pilulifera, 83

Corallina pinnatifolia, 81, 82

Corallina pinnatifolia var. 

digitata, 80, 82, 83, 481

Corallina pinnatifolia var. 

pinnatifolia, 80, 81, 82, 

83, 481

Corallina polysticha, 80, 82, 

83, 481

Corallina rosea, 85

Corallina rubens, 89, 92

Corallina rugosa, 57

Corallina subulata, 85

Corallina tenella, 91

Corallina vancouveriensis, 

80, 81, 82, 83, 84, 481

Corallina vancouveriensis var.

aculeata, 84

Corallina vancouveriensis var.

densa, 84

Corallina vancouveriensis var. 

lycopodioides, 84

“Corallina X”, 84

Corallinaceae, 34, 77, 78, 471, 

476, 477

Corallinaceae subfam. 

Amphiroideae, 77, 92, 101

Corallinaceae subfam. 

Corallinoideae, 77, 79,

84, 92

 Corallinaceae subfam. 

­Hydrolithoideae, 78, 115

Corallinaceae subfam.

­Lithophylloideae, 77, 92, 

101, 102

Corallinaceae subfam.

Lithothamnioideae, 133

 Corallinaceae subfam.

Mastophoroideae, 78, 103, 

118

Corallinaceae subfam.

Melobesioideae, 133

Corallinaceae subfam. Neogoniolithoideae, 77, 127

Corallinaceae subfam. Porolithoideae, 78, 129

Corallinales, 11, 12, 76, 77, 

131, 473, 476, 477

Corallinoideae tribus Corallineae, 79

Corallinoideae tribus Janieae,

79, 84, 132

Corallinophycidae, 34, 76

Corallophila, 157, 193, 194

Corallophila bella, 194, 194, 

195, 485

Corallopsis excavata, 457

Cordylecladia, 

Cordylecladia andersonii, 

383, 397

Cordylecladia lemaneiformis, 

398

Corynecladia, 249

Crassitegula, 440

Crossocarpaceae, 319, 338, 

344, 473

Crouania, 150, 153, 154

Crouania attenuata, 154, 

154, 484

Crouania pleonospora, 154

Crouaniella, 155

Crouaniella mcnabbii, 155

Crouanophycus, 150, 155

Crouanophycus latiaxis, 155

Crouanophycus mcnabbii, 

155, 156, 157, 158, 484

Cruoriella, 366, 367, 369, 371, 

372

Cruoriella armorica, 367

Cruoriella fissurata, 367,

368, 492

Cruoriella hancockii, 371

Cruoriella japonica, 369, 371

Cruoriella martii, 367

Cruoriella mexicana, 367, 368,

368, 369, 371, 372, 492

Cruoriopsis, 367, 369

Cruoriopsis crucialis, 367

Cruoriopsis japonica, 368, 

369, 371

Cruoriopsis mexicana, 368, 

368, 369, 492

Cryptonemia, 406, 408, 410

Cryptonemia angustata, 406, 

407, 410, 494

Cryptonemia borealis, 407

Cryptonemia decolorata, 406

Cryptonemia guaymasensis, 

406, 408, 408, 409, 494

Cryptonemia limensis, 408, 

409

Cryptonemia obovata, 406, 

407, 409, 409, 410, 494

Cryptonemia opuntioides, 

406, 408, 410, 478, 494

Cryptonemia veleroae, 406, 

407, 410, 478

Cryptonemiaceae, 405

Cryptonemiales, 143, 318, 405, 

426, 476, 478

Cyanidiophyceae, 13

Cyanidiophyta, 13

Cyanidiophytina, 13

Cystocloniaceae, 319, 320, 321

Cystoseira compressa, 19

Dasya, 204, 208

Dasya baillouviana, 206

Dasya baillouviana var. 

nudicaulis, 206

Dasya baillouviana var. 

stanfordiana, 204

Dasya californica, 208

Dasya eastwoodiae, 208

Dasya pedicellata, 204, 206

Dasya pedicellata var. 

nudicaulis, 206

Dasya pedicellata var. 

stanfordiana, 204 

Dasya pedicellata subsp. 

stanfordiana, 204, 205, 

206, 476, 486

Dasya pedicellata subsp. 

stanfordiana var. nudicaulis, 204, 206, 207, 476, 

478, 486

Dasya sinicola var. abyssicola, 

208, 209

Dasya sinicola var. californica, 

204, 208, 208, 209, 486

Dasya sinicola var. sinicola, 

204, 208, 208, 209, 486

Dasya spinigera, 204, 208,

209, 210, 486

Dasya stanfordiana, 204, 206

Dasyaceae, 149, 203, 204, 476, 

478

Dasyaceae subfam. Dasyoideae, 

204

Dasyaceae subfam. Heterosiphonioideae, 210

Delesseria, 

Delesseria bipinnatifida, 216, 

218

Delesseria californica, 221, 

222, 233

Delesseria filicina, 411

Delesseria leprieurii, 220, 221

Delesseria subgen. Caloglossa, 

218

Delesseria woodii, 216

Delesseriaceae, 34, 149, 212,

214, 473, 478

Dendrymenia, 

Dendrymenia hancockii, 468

Dermatolithon, 112

Dermatolithon ascripticium, 

114

Dermatolithon canescens, 113

Dermatolithon corallinae, 103

Dermatolithon dispar, 113, 

114

Dermatolithon pustulatum, 

114

Dermatolithon pustulatum f. 

ascripticium, 114

Dermatolithon veleroae, 113

Dermonema, 62

Dermonema frappieri, 63

Dermonema pulvinatum,63

Dermonema virens, 62, 63

Dichotomaria, 52, 53

Dichotomaria fragilis, 62

Dichotomaria marginata, 52, 

53, 54, 55, 56, 480

Dichotomaria spathulata, 52, 

53, 55, 55, 56, 480, 485, 

486

Dichotomaria tenera, 54

Dicranema, 325, 326

Dicranema rosaliae, 326,

326, 327, 491

Dicranemataceae, 319, 325

Dictyota, 19, 21, 25, 49, 113, 

116, 117, 120, 124, 157, 

210, 268, 480, 484, 485

Dictyota binghamiae, 124

Dictyopteris, 49, 116, 124, 210, 

484

Dictyopteris undulata, 490

Digenea, 114, 239, 242, 243, 

443

Digenea simplex, 16, 243,

244, 488

Dilsea, 

Dilsea californica, 434

Dione, 27

Dudresnaya, 327

Dudresnaya colombiana, 

327, 328, 491

Dumontiaceae, 319, 327, 364, 

366

Echinocaulon, 313

Echinocaulon acerosum, 313

Endocladia, 

Endocladia complanata, 320

Endosiphonia, 132

Epilithon, 137

Epilithon membranaceum, 

139

Epymenia, 465

Erythrocladia, 17, 18, 25

Erythrocladia endophloea, 18

Erythrocladia irregularis, 18,

18, 19, 25, 479

Erythrocladia irregularis f. 

subintegra, 25

Erythrocladia recondita, 18

Erythrocladia subintegra, 18, 

19, 25

Erythrocystis, 

Erythrocystis saccata, 254

Erythroglossum, 214, 221

Erythroglossum bipinnatifidum, 216

Erythroglossum californicum, 

221, 222, 233, 487

Erythroglossum delicatulum, 

233

Erythroglossum divaricatum, 

233

Erythroglossum obcordatum, 

222

Erythropeltidaceae, 17

Erythropeltidales, 17

Erythropeltis, 17, 19, 23

Erythropeltis discigera, 19,

23, 24

Erythropeltis subintegra, 25

Erythrophyllum, 344

Erythrophyllum delesserioides, 342, 344

Erythrotrichia, 17, 19, 20, 21

Erythrotrichia ascendens, 20
548 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Erythrotrichia (continued)

Erythrotrichia biseriata, 20, 

20, 21, 479

Erythrotrichia boryana, 24

Erythrotrichia californica, 22, 

23, 480

Erythrotrichia carnea, 20, 21, 

22, 23

Erythrotrichia carnea f. 

tenuis, 20, 21, 21, 22, 479

Erythrotrichia ceramicola, 21

Erythrotrichia ciliaris, 24

Erythrotrichia discigera, 19

Erythrotrichia irregularis, 18

Erythrotrichia parksii, 22

Erythrotrichia parksii var. 

minor, 20, 22, 22, 479

Erythrotrichia polymorpha, 25

Erythrotrichia tetraseriata, 

20, 22, 23, 480

Erythrotrichiaceae, 17

Erythrotrichopeltis, 19, 23

Erythrotrichopeltis boryana, 24

Erythrotrichopeltis ciliaris, 

19, 24

Eschara, 

Eschara fragilis, 62

Estebania, 452, 453

Estebania conjuncta, 453

Ethelia, 370

Ethelia mexicana, 369, 370

Eucheuma, 361, 473

Eucheuma johnstonii, 361, 

363

Eucheuma uncinatum, 361, 

363

Euhymenia, 

Euhymenia limensis, 409

Eurhodophycidae, 25

Eurhodophytina, 13, 25, 149

Eurotiomycetes, 35

Euthroa, 338

Falkenbergia, 143, 144, 146

Falkenbergia hillebrandii, 

143, 144, 146

Falkenbergia hillebrandiiphase of Asparagopsis, 

146, 483

Falkenbergia-phase of Asparagopsis, 144, 146, 146

Fauchea, 449, 450

Fauchea hoshawii, 450

Fauchea laciniata, 450

Fauchea mollis, 450

Fauchea repens, 449

Fauchea sefferi, 450

Faucheaceae, 442, 449, 476, 

478

Florideophyceae, 12, 13, 26, 

34, 142

Fosliella, 116, 117, 118, 121,

122, 123

Fosliella ascriptica, 114

Fosliella chamaedoris, 116

Fosliella dispar, 113

Fosliella farinosa, 116, 120

Fosliella lejolisii, 123

Fosliella minutula, 123

Fosliella nicholsii, 124

Fosliella? paschalis, 79, 116, 

119, 122

Fucus, 

Fucus acerosus, 313

Fucus acicularis, 330

Fucus acicularis var. β ustulatus, 320

Fucus baillouviana, 206

Fucus capillaceus, 317

Fucus cartilagineus, 437, 439

Fucus crinalis, 306, 307

Fucus dasyphyllus, 242

Fucus filamentosus, 290

Fucus gracilis, 382

Fucus longissimus, 396

Fucus miniatus, 363

Fucus ovatus, 447

Fucus pinnatifidus, 259

Fucus plicatus, 141

Fucus pusillus, 310

Fucus ramosissimus, 259

Fucus squamarius, 371

Fucus taxiformis, 144

Fucus valentiae, 324

Fucus verrucosus, 396

Fuscifolium, 30

Galaxaura, 20, 39, 51, 52, 53, 

56, 60, 62

Galaxaura arborea, 55, 56

Galaxaura constipata, 62

Galaxaura cylindrica, 60

Galaxaura delabida, 57

Galaxaura fastigiata, 61

Galaxaura fragilis, 62

Galaxaura lapidescens, 57

Galaxaura marginata, 53, 

55, 56

Galaxaura oblongata, 60, 

61, 62

Galaxaura ramulosa, 52, 57, 

58, 480

Galaxaura rugosa, 52, 57, 

59, 60, 480

Galaxaura sect. Eugalaxaura, 62

Galaxaura spathulata, 55

Galaxaura squalida, 57

Galaxaura subfruticulosa, 57

Galaxaura subverticillata, 57

Galaxaura ventricosa, 53

Galaxaura veprecula, 53, 56

Galaxauraceae, 50, 51, 52

Ganonema, 39, 63

Ganonema farinosum, 38, 

63, 64, 481

Gardneriella, 352

Gardneriella tubifera, 352

Gastroclonium, 199, 270, 442, 

444, 445, 447

Gastroclonium clavatum, 447

Gastroclonium compressum, 

444, 447, 495

Gastroclonium cylindricum, 

447

Gastroclonium ovale, 447

Gastroclonium ovatum, 447

Gastroclonium pacificum, 

199, 447, 448, 495

Gastroclonium parvum, 447, 

448

Gayliella, 157, 179, 195, 196, 

198, 485

Gayliella fimbriata, 195,

196, 485

Gayliella mazoyerae, 198

Gayliella recticortica, 195, 

198, 198, 199, 486

Gayliella species A, 195, 196,

197, 198, 478, 486

Gayliella taylorii, 195, 199,

200, 486

Gayliella transversalis, 198

Gelidiaceae, 304, 305, 309, 312, 

363, 404, 455, 478

Gelidiales, 12, 34, 142, 304,

305, 316, 363, 404, 473, 

476, 478

“Gelidieae”, 305

Gelidiella, 312, 314, 313

Gelidiella acerosa, 313, 314

Gelidiella adnata, 313

Gelidiella fanii, 314

Gelidiella hancockii, 306, 

313, 314, 314

Gelidiella mexicana, 306, 314

Gelidiella? refugiensis, 312

Gelidiellaceae, 304, 305, 312,

313, 363

Gelidiocolax, 404

Gelidiocolax microsphaericus, 404

Gelidiopsis, 21, 326, 371, 377, 

455, 485

Gelidiopsis gracilis, 456

Gelidiopsis tenuis, 455

Gelidiopsis variabilis, 455, 

456, 457

Gelidium, 21, 22, 28, 41, 45, 

47, 114, 138, 184, 188, 

190, 193, 268, 305, 306, 

307, 310, 315, 404, 455, 

480, 482, 484, 485, 490

Gelidium amansii, 308

Gelidium caloglossoides, 317

Gelidium capillaceum, 317

Gelidium corneum, 24, 480

Gelidium corneum var. 

capillaceum, 317

Gelidium coronadense, 306

Gelidium coulteri, 312

Gelidium crinale, 306, 307, 

311, 490

Gelidium crinale var. crinale, 

311

Gelidium crinale f. luxurians, 

315

Gelidium crinale var. luxurians, 

315

Gelidium decompositum, 

306, 307, 308, 317, 318, 

478, 490

Gelidium elegans, 309

Gelidium johnstonii, 306, 

308, 309, 489, 490

Gelidium lanceolata, 423

Gelidium mcnabbianum, 

306, 307, 309, 310, 490

Gelidium microdentatum, 306

Gelidium microphysa, 306,

307, 310

Gelidium pulchrum, 405

Gelidium purpurascens, 405

Gelidium pusillum, 306, 307, 

310, 310, 311, 316, 405, 

491

Gelidium pyramidale, 317

Gelidium refugiensis, 306, 

307, 312, 478

Gelidium sclerophyllum, 28, 

306, 307, 312

Gelidium sonorense, 316, 

317

Gelidium tsengii, 309

Gelidium variabile, 456

Gelidium variabilis, 457

Gibsmithia, 327

Gigartina, 

Gigartina acicularis, 330

Gigartina canaliculata, 334

Gigartina chauvinii, 331

Gigartina diffusa, 335

Gigartina digitata, 335

Gigartina eatoniana, 415

Gigartina gaudichaudii, 358

Gigartina hancockii, 337

Gigartina intermedia, 330, 

331, 333, 334

Gigartina johnstonii, 331

Gigartina lemaneiformis, 398

Gigartina leptorhynchos, 337

Gigartina macdougalii, 331, 

332

Gigartina papillata, 331

Gigartina pectinata, 331, 332

Gigartina spinella, 324

Gigartina teedii, 333

Gigartina tenella, 330

Gigartina tenera, 358

Gigartina tepida, 333

Gigartinaceae, 319, 328, 329, 

473, 475, 476, 478

Gigartinales, 12, 142, 143, 318,

319, 405, 455, 471, 475, 

476, 478

Ginnania, 

Ginnania undulata, 70

Gloiocladia, 449, 450, 452

Gloiocladia conjuncta, 453

Gloiocladia furcata, 449, 452
NUMBER 96 • 549

Gloiocladia hoshawii, 450,

451, 476, 478, 495

Gloiocladia laciniata, 450

Gloiocladia mollis, 450, 452, 

476, 478, 495

Gloiocladia repens, 449

Gloiocladia sefferi, 450, 452, 

476, 478, 495

Gloiocladiaceae, 449

Gloioderma, 449, 452, 453

Gloioderma australe, 452

Gloioderma conjuncta, 453,

454, 478, 495

Gloiophloea, 68

Gloiophloea confusa, 69

Gloiosiphonia, 449

Gloiosiphoniaceae, 367

Goniolithon, 

Goniolithon onkodes, 130

Goniolithon pallescens, 108

Goniolithon subgen. Hydrolithon, 115

Goniolithon yendoi, 126

Goniotrichiceae, 13

Goniotrichum, 

Goniotrichum alsidii, 15

Goniotrichum cornu-cervi, 15

Goniotrichum elegans, 15

Goniotrichum elegans var. 

alsidii, 15

Goniotrichum ramosum, 14

Gracilaria, 114, 120, 153, 268, 

271, 361, 363, 374, 375,

379, 382, 383, 386, 390, 

391, 394, 395, 396, 397, 

403, 404

Gracilaria andersonii, 382, 

383

Gracilaria ascidiicola, 375, 

376, 377, 478, 492

Gracilaria asiatica, 393

Gracilaria bursa-pastoris, 388

Gracilaria chilensis, 394

Gracilaria compressa, 388

Gracilaria confervoides, 382

Gracilaria crispata, 376, 377,

378, 379, 404, 493

Gracilaria crockeri, 392

Gracilaria cunninghamii, 

376, 378, 380, 392, 393, 

396, 404

Gracilaria galetensis, 468

Gracilaria (Gracilariopsis?) 

papenfussii, 383

Gracilaria gracilis, 382

Gracilaria guaymasensis, 382

Gracilaria hancockii, 394, 396

Gracilaria incurvata, 396

Gracilaria johnstonii, 392, 

394, 396

Gracilaria lacerata, 377

Gracilaria lemaneiformis, 

382, 383, 397, 398, 402

Gracilaria marcialana, 376, 

380, 478

Gracilaria megaspora, 403

Gracilaria pachydermatica, 

376, 380, 381, 493

Gracilaria pacifica, 375, 382,

383, 393, 394, 396

Gracilaria papenfussii, 375, 

382, 383, 393, 394, 396

Gracilaria pinnata, 360, 375, 

383, 384, 385, 388, 478, 

493

Gracilaria ramisecunda, 375, 

376, 385, 385, 493

Gracilaria rhodotricha, 393, 

403

Gracilaria rubrimembra, 

376, 379, 386, 387, 478, 

493

Gracilaria sinicola, 394

Gracilaria sjoestedtii, 383, 

397, 398, 402, 404

Gracilaria sp., 271

Gracilaria spicifera, 321

Gracilaria spinigera, 376, 

379, 386, 388, 389, 478, 

493

Gracilaria subsecundata, 

375, 383, 388, 389, 390, 

396, 478, 493

Gracilaria tenuifolia, 392

Gracilaria tenuistipitata, 394

Gracilaria tepocensis, 376, 

389, 390, 391, 392, 469, 

478, 493

Gracilaria textorii, 394, 396,

404

Gracilaria textorii var. 

cunninghamii, 378

Gracilaria turgida, 376, 380, 

391, 392, 493

Gracilaria veleroae, 376, 

379, 390, 392, 393, 493

Gracilaria vermiculophylla, 

375, 383, 393, 394, 396, 

403

Gracilaria verrucosa, 382, 

393, 394, 396

Gracilaria vivesii, 376, 380, 

392, 394, 395, 396, 478, 

493

Gracilaria vivipara, 394

Gracilariaceae, 374, 375, 404, 

455, 475, 478

Gracilariales, 12, 142, 143, 374, 

404, 471, 473, 475, 478

Gracilariophila, 374, 375, 378, 

403, 404

Gracilariophila gardneri, 

378, 404

Gracilariophila oryzoides, 404

Gracilariopsis, 374, 375, 382, 

383, 396, 397, 402, 403, 

404, 472

Gracilariopsis andersonii, 

33, 382, 383, 396, 397, 

398, 402, 403, 404

Gracilariopsis animasensis, 

382, 396, 397, 398, 399, 

400, 401, 402, 403, 475, 

493, 494

Gracilariopsis chorda, 394

Gracilariopsis lemaneiformis, 

383, 397, 398, 402, 403

Gracilariopsis longissima, 

396, 397

Gracilariopsis megaspora, 

397, 403

Gracilariopsis rhodotricha, 

393, 397, 403

Gracilariopsis sjoestedtii, 

383, 397, 398, 402

“Gracilariopsis sp. 1”, 398, 

403

“Gracilariopsis sp. Australia”, 

398

Gracilariopsis vermiculophylla, 393

Grateloupia, 75, 76, 151, 190, 

406, 410, 411, 412, 423, 

434

Grateloupia abreviata, 417

Grateloupia acroidalea, 425

Grateloupia americana, 423

Grateloupia avalonae, 412

Grateloupia catenata, 411,

412, 413, 494

Grateloupia cornea, 425

Grateloupia dactylifera, 411, 

413, 478

Grateloupia doryphora, 75, 

411, 417

Grateloupia filicina, 411, 415

Grateloupia filicina var. 

lomentaria, 411, 412

Grateloupia filicina var. porracea f. lomentaria, 411

Grateloupia hancockii, 411, 

413, 413, 494

Grateloupia howei, 411, 413,

414, 415, 494

Grateloupia johnstonii, 331

Grateloupia lanceolata, 423

Grateloupia porracea, 411, 

412

Grateloupia prolongata, 151, 

190, 411, 415, 416, 494

Grateloupia setchellii, 417

Grateloupia sternbergii var. 

versicolor, 415

Grateloupia? squarrulosa, 

331

Grateloupia turuturu, 411

Grateloupia versicolor, 411, 

415, 417, 494

Grateloupia versicolor var. 

prostrata, 417

Grateloupia violacea, 410, 

411, 417, 418, 434, 478, 

494

Grateloupiaceae, 405

Griffithsia, 25, 291, 295

Griffithsia anthericephala, 

292

Griffithsia chilensis, 295

Griffithsia furcellata, 292

Griffithsia multiramosa, 292

Griffithsia multiramosa var. 

balboensis, 292

Griffithsia multiramosa var. 

minor, 293

Griffithsia pacifica, 292, 295,

295, 490

Griffithsia secunda, 293

Griffithsia tenuis, 294, 295

Griffithsia thyrsigerum, 294, 

295

Grinnellia, 214, 222, 223

Grinnellia lanceolata, 222,

223, 487

Gymnogongrus, 138, 346, 349

Gymnogongrus? carnosus, 

349, 478

Gymnogongrus divaricatus, 

346

Gymnogongrus guadalupensis, 349, 350

Gymnogongrus hancockii, 

346, 347, 348

Gymnogongrus johnstonii, 

346, 347, 348, 349, 350,

351, 492

Gymnogongrus leptophyllus, 

348

Gymnogongrus serenei, 348, 

349

Gymnogongrus sinicola, 382

Gymnophlaeaceae, 430

Haematocelis, 434

Haematocelis-like, 434

Haematocelis-phase, 432

Haematocelis zonalis, 434

Haliptilon, 77, 79, 84, 85, 132

Haliptilon gracile var.

gracile, 85

Haliptilon gracile var. verticillatum, 85

Haliptilon roseum var. 

roseum, 85

Haliptilon roseum var. verticillatum, 85, 476

Haliptilon squamatum, 133

Haliptilon subulatum, 85

Halymenia, 18, 20, 39, 75, 76, 

365, 366, 406, 417, 418, 

419

Halymenia abyssicola, 421

Halymenia actinophysa, 364, 

419, 420, 421, 494

Halymenia agardhii, 440

Halymenia bifida, 418, 419,

478

Halymenia californica, 75, 

420, 421, 479

Halymenia coccinea, 364

Halymenia flabellata, 440
550 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Halymenia (continued)

Halymenia gardneri, 364, 

421

Halymenia megaspora, 421,

422, 478, 494

Halymenia polydactyla, 440

Halymenia refugiensis, 419

Halymenia sect. Sebdenia, 440

Halymenia templetonii, 365, 

421

Halymeniaceae, 143, 405, 406, 

478

Halymeniales, 405, 426

Hapalidiaceae, 77, 131, 132

Hapalidiaceae subfam.

Choreonematoideae, 132

Hapalidiaceae subfam.

­Melobesioideae, 77, 103, 

132, 133

Hapalidium, 137

Haplocladium, 166

Haplocladium floccosum, 166

Herposiphonia, 238, 244, 245

Herposiphonia hollenbergii, 

245

Herposiphonia littoralis, 245,

245, 488

Herposiphonia parva, 246

Herposiphonia plumula var. 

parva, 245, 246, 247, 488

Herposiphonia plumula var.

plumula, 245, 246, 247, 

488

Herposiphonia pygmaea, 246

Herposiphonia rigida, 246

Herposiphonia secunda, 245

Herposiphonia secunda f. 

tenella, 246

Herposiphonia spinosa, 245, 

247, 248, 488

Herposiphonia subdisticha, 

246, 247

Herposiphonia tenella, 245, 

246

Herposiphonia verticillata, 245

Heteroderma, 78, 103, 115, 

118, 119, 121, 123

Heteroderma chamaedoris, 

116, 120

Heteroderma corallinicola, 

103, 119, 120, 477, 482

Heteroderma gibbsii, 117, 

119, 120, 120, 121, 477, 

482, 483

Heteroderma lejolisii, 123

Heteroderma minutula, 123

Heteroderma nicholsii, 120, 

124

Heteroderma subtilissimum, 

119, 120, 121, 483

Heterosiphonia, 204, 210

Heterosiphonia crispella var. 

crispella, 212

Heterosiphonia crispella var.

laxa, 210, 211, 212, 486

Heterosiphonia erecta, 210, 

212, 213, 486

Heterosiphonia sinicola, 208

Heterosiphonia wurdemannii 

var. laxa, 210, 212

Heterosiphonia wurdemannii 

var. wurdemannii, 212

Hildenbrandia, 35, 36

Hildenbrandia canariensis

var. dawsonii, 36

Hildenbrandia dawsonii, 36

Hildenbrandia occidentalis, 37

Hildenbrandia prototypus, 

36, 36, 37, 480

Hildenbrandia rosea, 36, 37

Hildenbrandia rubra, 36, 37

Hildenbrandiaceae, 35, 473

Hildenbrandiales, 35

Hildenbrandiophycidae, 35

“Hildenbrandtia,” 35

Hincksia, 15

Holmsella, 404

Hommersandia, 

Hommersandia palmatifolia, 

344

Hooperia, 

Hooperia baileyana, 459

Hormospora, 

Hormospora ramosa, 14

Hutchinsia, 

Hutchinsia pennata, 280

Hutchinsia secunda, 245

Hutchinsia tenella, 246

Hydrolithon, 78, 79, 115, 116, 

117, 118, 119, 122, 127, 

129, 130

Hydrolithon chamaedoris, 116

Hydrolithon conicum, 123

Hydrolithon decipiens, 125

Hydrolithon discoideum, 111

Hydrolithon farinosum, 116,

117, 122, 482

Hydrolithon onkodes, 129, 

130

Hydrolithon reinboldii, 116

Hydrolithon samoënse, 116, 

117, 118, 130

Hydrolithon setchellii, 127

Hydropuntia, 383

Hymenoclonium,147

Hymenoclonium-phase, 147

Hymenoclonium serpens, 147

Hypnea, 153, 321, 325

Hypnea californica, 325

Hypnea cervicornis, 321, 

322, 322, 324, 491

Hypnea charoides, 325

Hypnea coulteri, 358

Hypnea esperi, 320, 322, 324

Hypnea evermannii, 325

Hypnea flexicaulis, 325

Hypnea johnstonii, 322, 323

Hypnea marchantae, 325

Hypnea musciformis var. 

valentiae, 324

Hypnea nidifica, 324

Hypnea nidulans, 323, 324

Hypnea pannosa, 321, 323,

324

Hypnea spicifera, 321

Hypnea spinella, 322, 324

Hypnea valentiae, 321, 324,

325

Hypnea valentiae var.

gardneri, 325

Hypnea volubilis, 321, 325

Hypneaceae, 320

Hypneocolax, 321, 325

Hypoglossum, 214, 223

Hypoglossum abyssicolum, 

224

Hypoglossum attenuatum 

var. abyssicolum, 224,

225, 487

Hypoglossum attenuatum 

var. attenuatum, 224

Hypoglossum bipinnatifidum, 

216

Hypoglossum gregarium, 

215, 216, 487

Hypoglossum leprieurii, 221

Hypoglossum sagamianum, 

223

Iridaea,

Iridaea lacera, 344

Iridaea oblongifructa, 345

Irtugovia, 157, 166

Irtugovia pacifica, 166, 167

Irvinea, 460, 461, 464, 465

Irvinea ardreana, 465

Irvinea hancockii, 461, 465,

466, 496

Isymenia, 

Isymenia flabellata, 440

Itonoa, 429, 434

Izziella, 63, 64, 65

Izziella abbottiae, 65

Izziella orientalis, 65

Janczewskia, 248

Jania, 15, 77, 79, 84, 85, 86,

88, 91, 92, 93, 121, 132, 

133, 243

Jania adhaerens, 86, 87, 88, 

89, 481

Jania capillacea, 8, 9, 86, 

88, 89

Jania crassa, 88, 91

Jania decussato-dichotoma, 

86, 87, 89

Jania huertae, 86, 89, 90, 481

Jania longiarthra, 86, 88, 90,

91, 481

Jania mexicana, 86, 88, 91, 

481

Jania pacifica, 86, 91

Jania rosea, 85

Jania rubens, 89, 92

Jania sect. Haliptylon, 84

Jania subpinnata, 86

Jania tenella var. tenella, 86, 

91, 92

Jania tenella var. zacae, 86, 92

Joculator, 

Joculator pinnatifolius, 81

Kallymenia, 39, 75, 338, 340, 

344, 473

Kallymenia angustata, 406

Kallymenia baldwinii, 339,

340, 478, 491

Kallymenia bleckii, 338, 339,

340, 478, 491

Kallymenia guaymasensis, 408

Kallymenia norrisii, 338

Kallymenia oblongifructa, 345

Kallymenia pertusa, 75, 338, 

339, 341, 478, 491

Kallymenia reniformis, 344

Kallymenia tenuifolia, 407

Kallymenia veleroae, 410

Kallymeniaceae, 319, 327, 338,

342, 344, 345, 473, 478

Kallymeniopsis, 338, 344

Kallymeniopsis lacera, 344, 

345

Kallymeniopsis oblongifructa, 339, 342, 344, 345

Kappaphycus, 361

Kintarosiphonia, 282

Kintarosiphonia fibrillosa, 282

Kylinia, 

Kylinia arcuata, 40

Kylinia crassipes, 41

Kylinia microscopicum, 42

Kylinia porphyrae, 42

Kylinia secundata, 40, 43

Kylinia seriaspora, 40, 43

Laurencia, 114, 120, 122, 138, 

184, 190, 191, 192, 239, 

249, 250, 254, 255, 256, 

259, 444, 485, 495

Laurencia aguilar-rosasorum, 

250, 251, 252, 253, 254, 

475, 478, 488

Laurencia blinksii, 256, 257

Laurencia decidua, 250

Laurencia estebaniana, 257

Laurencia fenicalii, 250, 251, 

252, 253, 254, 475, 478, 

488

Laurencia flexilis, 250

Laurencia glandulifera, 255, 

259

Laurencia hancockii, 250, 253

Laurencia intermedia, 254

Laurencia iriei, 250, 251, 

252, 253, 254, 475, 478, 

485, 488

Laurencia johnstonii, 250, 

251, 254, 488

Laurencia lajolla, 250, 254,

255
NUMBER 96 • 551

Laurencia masonii, 250

Laurencia obtusiuscula, 254

Laurencia pacifica, 250, 252, 

253, 255, 261

Laurencia paniculata, 255, 

259, 260, 261, 476

Laurencia papillosa, 259

Laurencia papillosa var. 

pacifica, 261

Laurencia pinnatifida, 256, 

259, 261

Laurencia richardsii, 250

Laurencia scrippsensis, 258

Laurencia sect. Palisadae, 

258

Laurencia sect. Pinnatifidae, 

256

Laurencia sinicola, 258

Laurencia sp., 250, 253

Laurencia sp. I, 252, 253

Laurencia sp. II, 253, 254

Laurencia sp. III, 250

Laurencia subcorymbosa, 250

Laurencia subgen. Laurencia,

249

Laurencia subgen. Chondrophycus, 249, 255

Laurencia subgen. Saitoa, 256

Laurencia thuyoides, 259, 260

Laurencia voragina, 250

Laurenciella, 249

Lejolisia, 291, 296

Lejolisia colombiana, 296, 

297

Lejolisia hoshawii, 296, 297,

297, 478, 490

Lejolisia sp. nov., 297

Leptocladia,

Leptocladia peruviana, 18

Leptophytum, 136

Leptophytum leave, 136

Leptophytum microsporum, 

135, 136

Leptosiphonia, 274

Leptosiphonia schousboei, 

274

Leptosomia, 

Leptosomia rosea, 469

Lesleigha, 440

Liagora, 39, 63, 65, 66

Liagora abbottiae, 66

Liagora californica, 66

Liagora ceranoides, 66, 66, 

67, 481

Liagora ceranoides f. 

leprosa, 67

Liagora ceranoides f. pulverulenta, 67

Liagora ceranoides var. 

pulverulenta, 67

Liagora farinosa, 38, 63

Liagora leprosa, 67

Liagora magniinvolucra, 66, 

67, 67, 477, 481

Liagora orientalis, 65

Liagora pulverulenta, 67

Liagora tanakae, 65

Liagoraceae, 38, 50, 51, 62, 63, 

473, 477

Lictoria, 

Lictoria taxiformis, 144

Litholepis, 78, 101, 102, 103

Litholepis accola, 137, 138

Litholepis caspica, 102

Litholepis sonorensis, 102, 

103, 482

Lithophylloideae tribus 

Amphiroeae, 93

Lithophyllum, 78, 102, 104, 

107, 111, 112

Lithophyllum accola, 137

Lithophyllum ascripticum, 

114

Lithophyllum australe, 134

Lithophyllum brachiatum, 

103

Lithophyllum californiense, 

103

Lithophyllum canescens, 113

Lithophyllum chamaedoris, 

116, 120

Lithophyllum corallinae, 103

Lithophyllum decipiens, 125, 

126, 127

Lithophyllum dentatum, 104

Lithophyllum decussatum, 

112

Lithophyllum diguetii, 104, 

105, 108, 110, 477, 482

Lithophyllum discoideum, 

111

Lithophyllum dispar, 113

Lithophyllum elegans, 108

Lithophyllum elegans f.

angulata, 108

Lithophyllum farlowii, 112

Lithophyllum fuegianum, 111

Lithophyllum hancockii, 104, 

106, 106, 482

Lithophyllum hapalidiodides 

f. confine, 115

Lithophyllum imitans, 104, 

106, 107, 482

Lithophyllum leave, 136

Lithophyllum lichenare, 103

Lithophyllum lithophylloides, 

103, 104, 105, 108, 110

Lithophyllum lithophylloides

f. brachiatum, 103

Lithophyllum margaritae, 

104, 105, 107, 107, 108, 

110, 477, 482

Lithophyllum neofarlowii, 

111

Lithophyllum onkodes, 130

Lithophyllum orbiculatum, 

111

Lithophyllum pallescens, 

103, 104, 105, 108, 109, 

110, 129, 482

Lithophyllum proboscideum, 

104, 110, 110, 111, 482

Lithophyllum pustulatum, 

102, 112, 114

Lithophyllum pustulatum f. 

ascripticium, 114

Lithophyllum pustulatum f.

australis, 124

Lithophyllum reinboldii, 116

Lithophyllum samoënse, 117, 

118

Lithophyllum sonorensis, 102

Lithophyllum trichotomum, 

128

Lithophyllum tumidulum f. 

dispar, 113

Lithophyllum veleroae, 104, 

105, 108, 113

Lithophyllum whidbeyense, 

125

Lithophyllum yendoi, 126

Lithophyllum zostericola f. 

mediocris, 138

Lithoporella, 

Lithoporella accola, 137

Lithothamniaceae, 131

Lithothamnion, 77, 79, 133,

134, 136, 139, 141, 494

Lithothamnion aculeiferum, 

140

Lithothamnion australe, 134,

135, 483

Lithothamnion australe f.

americana, 134

Lithothamnion californicum

f. microsporum, 135

Lithothamnion corallioides f. 

australis, 134

Lithothamnion crassiusculum, 127, 136, 140, 141

Lithothamnion decipiens, 125

Lithothamnion dentatum, 104

Lithothamnion dentatum f. 

diguetii, 104

Lithothamnion diguetii, 104

Lithothamnion elegans, 108

Lithothamnion elegans f.

angulata, 108

Lithothamnion elegans f. 

complanata, 108

Lithothamnion engelhartii, 

140

Lithothamnion fruticulosum, 

127, 140

Lithothamnion lenormandii, 

135

Lithothamnion lithophylloides, 109

Lithothamnion margaritae, 

107

Lithothamnion marginatum, 

138

Lithothamnion mediocre, 138

Lithothamnion microsporum, 

134, 135, 135, 136, 483

Lithothamnion muelleri, 134, 

136

Lithothamnion onkodes, 130

Lithothamnion orbiculatum, 

111

Lithothamnion pacificum f. 

crassiusculum, 140

Lithothamnion pallescens, 108

Lithothamnion proboscideum, 110

Lithothamnion rugosum f. 

crassiusculum,136, 140

Lithothamnion setchellii, 127

Lithothamnion trichotomum, 

128

Lithothamnion yendoi, 126

Lithothamnium, 133

Lomentaria, 453, 457, 484

Lomentaria baileyana, 459

Lomentaria catenata, 457,

458, 459, 495

Lomentaria drouetii, 411

Lomentaria hakodatensis, 

457, 459, 459, 460, 496

Lomentaria sinensis, 459

Lomentariaceae, 304, 442, 453,

455, 476

Lophocladia, 286

Lophosiphonia, 273, 278

Lophosiphonia mexicana, 

272, 273

Lophosiphonia villum, 277

Lophothalia group, 286

Lysithea, 30

Mastocarpus, 

Mastocarpus papillatus, 331

Mastophora, 118

“Mastophoreae”, 118

Mazzaella, 329, 334, 335

Mazzaella affinis, 336, 337

Mazzaella diffusa, 335, 335, 

336, 476, 478, 491

Mazzaella digitata, 335, 336,

336, 476, 478, 491

Mazzaella hancockii, 335, 

336, 337, 491

Mazzaella leptorhynchos, 337

Melobesia, 79, 133, 136, 137, 

138, 139

Melobesia accola, 137, 138

Melobesia canescens, 113

Melobesia caspica, 102

Melobesia confinis, 115

Melobesia corallinae, 103

Melobesia deformans, 132

Melobesia farinosa, 116, 117

Melobesia gibbsii, 120

Melobesia (Heteroderma) 

canescens, 113

Melobesia lejolisii, 123

Melobesia lenormandii, 135

Melobesia marginata, 137, 138

Melobesia mediocris, 137, 

138
552 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Melobesia (continued)

Melobesia membranacea, 

137, 139

Melobesia minutulum, 123

Melobesia paschalis, 122

Melobesia pustulata, 112, 

114

Melobesia polystromatica, 

137, 139

Melobesia sect. Spongites, 124

Melobesia subgen. Litholepis, 

102

Melobesia subtilissima, 119, 

120

Melobesia thuretii, 132

Melobesiaceae, 131

Membranoptera, 

Membranoptera spatulata, 

215, 216

Mesogloia, 

Mesogloia attenuata, 154

Mesophyllum, 79, 133, 134, 

139, 140

Mesophyllum crassiusculum, 

127, 134, 136, 140, 140, 

141, 483

Mesophyllum engelhartii, 

140

Metamastophora, 118

Metapeyssonnelia, 366, 367, 

369, 370, 371, 473

Metapeyssonnelia corallipeda, 

369

Metapeyssonnelia feldmannii,

369

Metapeyssonnelia mexicana, 

369, 370, 371, 492

Metapeyssonnelia milleporoides, 369

Metapeyssonnelia sp. A, 370, 

371

Metarhodophytina, 13

Micropeuce, 

Micropeuce setosus, 287

Millepora, 

Millepora decussata, 112

Minerva, 27

Miuraea, 30

Murrayella, 219

Murrayellopsis, 287, 288

Murrayellopsis dawsonii, 288

Mycosphaerella, 35

Myriogramme, 214, 224, 226

Myriogramme auricularis, 

226, 226, 478, 487

Myriogramme bombayensis, 

232, 233

Myriogramme caespitosa, 

226, 227

Myriogramme divaricata, 

226, 227, 478, 487

Myriogramme osorioi, 227

Myriogramme sp., 226, 487

Myriogramme subdichotoma, 

233

Nemaliales, 12, 38, 50, 51, 477

Nemalionales, 50, 51

Nemalion, 

Nemalion pulvinatum, 63

Nemalion virens, 62

Nemaliophyceae, 34

Nemaliophycidae, 34, 37, 38

Nemastoma, 

Nemastoma nakamurae, 426

Nemastomales, 429

Nemastomaceae, 430

Nemastomataceae, 426, 429, 430

Nemastomatales, 143, 426, 

429, 473, 478

Neoagardhiella, 

Neoagardhiella baileyi, 353, 

358

Neoagardhiella coulteri, 358

Neoagardhiella gaudichaudii, 

358

Neogoniolithon, 78, 104, 127,

128

Neogoniolithon setchellii, 127

Neogoniolithon trichotomum, 

104, 128, 128, 129, 483

Neomonospora, 

Neomonospora furcellata, 292

Neomonospora multiramosa, 

292

Neosiphonia, 238, 261, 262, 

264, 265, 268, 270, 271, 

272, 273, 274, 276

Neosiphonia bajacali, 262

Neosiphonia beaudettei, 262

Neosiphonia cheloniae, 262, 

263, 263, 264, 476, 478, 

488

Neosiphonia concinna, 262, 

265, 270, 476, 489

Neosiphonia confusa, 262, 

265, 268, 269, 271, 476, 

489

Neosiphonia eastwoodae, 

262, 264, 265, 476, 489

Neosiphonia flaccidissima, 

262, 265, 266, 267, 489

Neosiphonia flavimaria, 263

Neosiphonia harveyi, 270

Neosiphonia johnstonii, 262, 

270, 265, 271, 476, 489

Neosiphonia masonii, 262, 

265, 267, 476, 489

Neosiphonia mexicana, 262, 

272, 272, 273, 476, 489

Neosiphonia paniculata, 262, 

273, 272, 273, 274, 476, 

489

Neosiphonia savatieri, 262, 

267, 267, 268, 489

Neosiphonia sect. Multisiphonia, 262, 263, 270, 475

Neosiphonia sect. Neosiphonia, 262, 263, 270

Neosiphonia simplex, 262, 

268, 269, 270, 489

Neosiphonia sphaerocarpa, 

262, 268

Neosiphonia sphaerocarpa 

var. cheloniae, 263

Neosiphonia tongatensis, 264

Norrissia, 

Norrissia setchellii, 417

Nothogenia, 68

Osmundea, 239, 249, 255, 256, 

257

Osmundea blinksii, 256, 257

Osmundea estebaniana, 256, 

257, 257, 258, 476, 478, 

488

Osmundea pinnatifida, 256, 

259

Osmundea purepecha, 256

Osmundea ramosissima, 259

Osmundea sinicola, 256, 

257, 258, 271, 488

Padina, 21, 22, 45, 92, 113, 

116, 117, 120, 123, 124, 

174, 196, 210, 270, 482, 

483, 485, 486, 488, 489

Padina arborescens, 113

Palisada, 239, 249, 255, 258,

259, 260, 261

Palisada flagellifera, 259

Palisada intermedia, 254

Palisada paniculata, 8, 9, 

255, 259, 260, 261, 286, 

476, 488, 490

Palisada papillosa, 259

Palisada pedrochei, 255, 259, 

260, 261, 475, 488

Palisada perforata, 259

Palisada thuyoides, 259, 261

Palmariaceae, 74

Palmariales, 38, 39, 74

Parviphycus, 313

Parviphycus adnata, 313

Petroderma, 

Petroderma maculiforme, 35

Petroglossum, 345, 350

Petroglossum parvum, 350,

352, 492

Peyssonnelia, 366, 367, 369, 

370, 371

Peyssonnelia armorica, 367, 

371

Peyssonnelia conchicola, 371

Peyssonnelia dawsonii, 369, 

370

Peyssonnelia hancockii, 371

Peyssonnelia inamoena, 374

Peyssonnelia japonica, 369, 

371

Peyssonnelia mariti, 367

Peyssonnelia mexicana, 369, 

371, 372, 372, 492

Peyssonnelia orientalis, 371, 

373, 373, 374, 492

Peyssonnelia pacifica, 371

Peyssonnelia rubra, 373

Peyssonnelia rubra f. orientalis, 373

Peyssonnelia rubra var. orientalis, 373

Peyssonnelia sp., 370

Peyssonnelia squamaria, 371

Peyssonneliaceae, 366, 367

Peyssonneliales, 11, 12, 142, 

366, 471, 473

Phrix, 

Phrix gregarium, 215

Phycodrys, 214, 227, 228

Phycodrys amplissima, 228,

229, 478, 487

Phycodrys lucasana, 228, 478

Phycodrys simplex, 228, 229, 

478, 487

Phyllactidium, 

Phyllactidium confervicola, 

123

Phyllodictyon, 21

Phyllophoraceae, 319, 345,

473, 475, 478

Phyllospadix, 49, 138, 212

Phymatolithon, 136

Phymatolithon lenormandii, 

135, 136

Pihiellales, 141

Placophora, 284, 286

Placophora group, 284, 285

Plagiospora, 367

Plagiospora gracilis, 367

Plantae, 12, 13

Platoma, 428, 430, 432, 433, 

434

Platoma abbottianum, 426, 

427, 428, 429

Platoma bairdii, 426

Platoma cyclocolpum, 429

Platoma? fanii, 431, 433,

434, 478

Platoma tenue, 432

Platoma tenuis, 432

Platysiphonia, 214, 236, 237

Platysiphonia clevelandii, 

237, 238

Platysiphonia decumbens, 

237, 237, 238, 488

Platysiphonia parva, 238

Platythamnion, 199

Platythamnion heteromorphum f. reversum, 201

Platythamnion orbignianum, 

201

Platythamnion pectinatum, 

201

Platythamnion pectinatum

var. laxum, 203

Platythamnion reversum, 201

Platythamnion tepocense, 203

Pleonosporium, 291, 300

Pleonosporium abysicola, 303

Pleonosporium dasyoides, 

300
NUMBER 96 • 553

Pleonosporium globuliferum, 

300, 301, 490

Pleonosporium mexicanum, 

300, 302, 302, 490

Pleonosporium rhizoideum, 

300, 302, 303

Pleonosporium saccorhiza, 

298

Pleonosporium squarrulosum, 

300

Pleonosporium vancouverianum, 300, 303, 303, 304, 

490

Plocamiaceae, 436, 475, 478

Plocamiales, 142, 436, 475, 

478

Plocamiocolax, 436

Plocamium, 436, 437

Plocamium cartilagineum, 

436, 437, 439

Plocamium cartilagineum 

subsp. pacificum, 439

Plocamium coccineum, 437, 

439

Plocamium coccineum var. 

pacificum, 439

Plocamium katinae, 437,

438, 439, 475, 478, 495

Plocamium lyngbyanum, 437

Plocamium maggsiae, 437

Plocamium nanum, 437

Plocamium pacificum, 439

Plocamium raphelisianum, 

437

Plocamium subtile, 437

Plocamium violaceum, 439

Pneophyllum, 78, 118, 119, 

122, 123

Pneophyllum confervicolum, 

123

Pneophyllum confervicolum f. 

minutulum, 123

Pneophyllum conicum, 123

Pneophyllum fragile, 123,

124

Pneophyllum lejolisii, 123

Pneophyllum nicholsii, 120, 

123, 124

Pneophyllum subtilissima, 

120

Pollexfenia, 286

Pollexfenia? anacapensis, 286

Polygonum sect. Echinocaulon, 

313

Polyneurella, 214, 228, 229

Polyneurella hancockii var.

hancockii, 229, 230, 231, 

487

Polyneurella hancockii var.

rhizoidea, 229, 230, 478

Polyochetum, 274

Polysiphonia, 25, 41, 176, 179, 

238, 262, 272, 274, 275, 

278, 485

Polysiphonia acuminata, 271

Polysiphonia aff. paniculata, 

274

Polysiphonia bajacali, 262

Polysiphonia beaudettei, 262

Polysiphonia bifurcata, 274

Polysiphonia californica, 273

Polysiphonia carettia, 264

Polysiphonia concinna, 265, 

270

Polysiphonia confusa, 265, 

271

Polysiphonia decussata, 274

Polysiphonia delicatula, 277

Polysiphonia dendroidea, 280

Polysiphonia dictyurus, 284

Polysiphonia eastwoodae, 264

Polysiphonia fibrillosa, 271

Polysiphonia flaccidissima, 

265, 266, 267

Polysiphonia harveyi, 270

Polysiphonia hendryi, 274

Polysiphonia hillebrandii, 

144, 146

Polysiphonia hollenbergii, 

274, 275, 275, 475, 478, 

489

Polysiphonia homoia, 274

Polysiphonia inconspicua, 

271

Polysiphonia japonica, 268

Polysiphonia japonica var.

savatieri, 268

Polysiphonia johnstonii, 265, 

270, 271

Polysiphonia johnstonii var. 

concinna, 270

Polysiphonia marchantae, 

271

Polysiphonia masonii, 265, 

267

Polysiphonia minutissima, 

268

Polysiphonia mollis, 264, 265

Polysiphonia mollis var. 

tongatensis, 264

Polysiphonia nathanielii, 274

Polysiphonia pacifica var. 

delicatula, 275, 276, 276, 

277, 489

Polysiphonia pacifica var.

disticha, 277

Polysiphonia pacifica var.

gracilis, 274

Polysiphonia pacifica var.

pacifica, 274, 277

Polysiphonia paniculata, 272, 

273, 274

Polysiphonia perpusilla, 235

Polysiphonia plumula, 246

Polysiphonia richardsoni, 271

Polysiphonia savatieri, 267, 

268

Polysiphonia schousboei, 274

Polysiphonia scopulorum, 

274, 278

Polysiphonia scopulorum var. 

villum, 274, 277, 278, 489

Polysiphonia sect. Oligosiphonia, 275

Polysiphonia senticulosa, 264

Polysiphonia sertularioides, 

266, 267

Polysiphonia simplex, 268, 270

Polysiphonia sinicola, 271

Polysiphonia snyderae, 264, 

489

Polysiphonia sonorensis, 272, 

274, 278, 279, 478, 489

Polysiphonia sp., 40, 275

Polysiphonia sphaerocarpa, 

262, 268

Polysiphonia sphaerocarpa

var. cheloniae, 263

Polysiphonia stricta, 274

Polysiphonia subtilissima, 

275, 279

Polysiphonia subtilissima var. 

abbottiae, 279

Polysiphonia tongatensis, 264

Polysiphonia urceolata, 19, 

25, 274

Polysiphonia verticillata, 245

Polysiphonia villum, 277, 278

Porolithon, 78, 115, 116, 118, 

129, 130, 131

Porolithon onkodes, 129, 130

Porolithon sonorense, 8, 9,

130, 131, 483

Porphyra, 11, 26, 27, 29, 30, 

33, 39, 40, 43

Conchocelis-phase of, 26, 

30, 33

Porphyra boryana, 24, 480

Porphyra hollenbergii, 31

Porphyra leucosticta, 31

Porphyra naiadum, 31

Porphyra nereocystis, 30

Porphyra pendula, 31, 32

Porphyra perforata, 30, 480

Porphyra perforata f. 

segregata, 31

Porphyra perforata var. 

segregata, 30

Porphyra purpurea, 30

Porphyra rediviva, 30

Porphyra rosengurtii, 30

Porphyra segregata, 31

Porphyra tenera, 30

Porphyra thuretii, 31, 32

Porphyra umbilicalis, 30

Porphyraceae, 26

Porphyridiophyceae, 13

Porphyridium,

Porphyridium cruentum, 12

Porphyridium purpureum, 12

Porphyropsis, 17

Porphyrostromium, 17, 19, 23,

24, 25

Porphyrostromium boryanum, 23, 24, 24, 480

Porphyrostromium boryi, 24

Porphyrostromium ciliare, 

19, 23, 24, 24, 480

Predaea, 430, 432, 433

Predaea japonica, 431, 431, 

432, 495

Predaea masonii, 428, 431, 

432

Predaea tenuis, 432

Prionitis, 76, 163, 199, 406, 

421, 423, 424, 485

Prionitis abbreviata var. 

abbreviata, 423, 424, 494

Prionitis abbreviata var. 

guaymasensis, 423, 424,

424, 478, 494

Prionitis acroidalea, 423, 

424, 425, 494

Prionitis australis, 426

Prionitis cornea, 423, 425

Prionitis delicatula, 316, 

423, 425, 426

Prionitis filiformis var. 

delicatula, 425

Prionitis guaymasensis, 424

Prionitis kinoensis, 425

Prionitis lanceolata, 423

Prionitis mexicana, 423

Prionitis sternbergii, 415

Psammophyllum, 222

Psammophyllum californicum, 222

Pseudobangia, 27

Pseudogloiophloea, 68

Pseudogloiophloea confusa, 

68, 69

Pseudolithophyllum, 102, 104, 

111

Pseudolithophyllum decipiens, 

125

Pseudolithophyllum discoideum, 111

Pseudolithophyllum fuegianum, 111

Pseudolithophyllum margaritae, 108

Pseudolithophyllum neofarlowii, 104, 111, 112

Pseudolithophyllum orbiculatum, 111

Pseudolithophyllum samoënse, 117

Pseudolithophyllum whidbeyense, 125

Pseudolithophyllum yendoi, 

126

Pseudoscinaia, 68

Pseudoscinaia snyderae, 

68, 69

Pterochondria, 282

Pterocladia, 114, 307, 308, 

310, 315, 316, 404

Pterocladia caloglossoides, 317

Pterocladia capillacea, 307, 

316, 317, 318
554 • SMITHSONIAN CONTRIBUTIONS TO BOTANY

Pterocladia (continued)

Pterocladia complanata, 317

Pterocladia mcnabbiana, 309, 

310

Pterocladia media, 315, 316

Pterocladia mexicana, 317

Pterocladia parva, 314, 317

Pterocladia pyramidale, 308, 

317, 318

Pterocladia sonorense, 315, 

316, 316, 318, 476, 478, 

491

Pterocladiaceae, 304, 305, 

312, 314, 315, 363, 476

Pterocladiella, 122, 314, 315, 

316, 317

Pterocladiella caloglossoides, 

314, 317

Pterocladiella capillacea, 

308, 316, 317, 318, 491

Pterocladiophila, 404

Pterocladiophilaceae, 374, 404

Pterosiphonia, 239, 279, 280, 

281, 282, 285

Pterosiphonia californica, 

280, 281, 489

Pterosiphonia dendroidea, 

280, 281, 288, 489

Pterosiphonia fibrillosa, 282

Pterosiphonia pennata, 280, 

282

Pterosiphonia spp., 40

Pterosiphonia tanakae, 282

Pterosiphoniella, 239, 281, 282

Pterosiphoniella williamsii, 

282, 283, 490

Pterothamnion, 157, 158, 199,

200, 203

Pterothamnion orbignianum, 

200, 201, 201

Pterothamnion pectinatum,

201, 202, 203, 486

Pterothamnion reversum, 201

Pterothamnion tepocense, 

201, 203, 478

Pugetia, 338, 342, 473

Pugetia fragilissima, 342

Pugetia mexicana, 342, 343, 

344, 491

Pugetia palmatifolia, 344

Pyropia, 12, 26, 27, 29, 30, 31, 

33, 34

Conchocelis-phase of, 26, 29, 

31, 33, 33, 34, 480

Pyropia californica, 30

Pyropia elongata, 30

Pyropia gardneri, 30

Pyropia hollenbergii, 30, 31, 

34, 477

Pyropia lanceolata, 30

Pyropia leucosticta, 31

Pyropia nereocystis, 30

Pyropia pendula, 30, 31, 32, 

33, 477, 480

Pyropia perforata, 30, 33

Pyropia raulaguilarii, 30

Pyropia suborbiculata, 30

Pyropia tenera, 30

Pyropia thuretii, 30, 31, 32, 

33, 480

Rhabdonia, 

Rhabdonia baileyi, 358

Rhabdonia coulteri, 358

Rhizophora,

Rhizophora mangle, 193, 

221, 240, 277

Rhizophyllidaceae, 366

Rhodachlya, 12, 37

Rhodachlyaceae, 12

Rhodachlyales, 12, 37

Rhodellophyceae, 13

Rhodellophytina, 13

Rhodochortaceae, 38

Rhodochorton, 38, 75

Rhodochorton arcuatum, 40

Rhodochorton daviesii, 45

Rhodochorton hancockii, 45, 

47

Rhodochorton microscopicum, 41, 42

Rhodochorton pacificum, 47

Rhodochorton plumosum, 47

Rhodochorton porphyrae, 

40, 42

Rhodochorton sinicola, 47, 49

Rhodochorton subimmersum, 75

Rhodochorton tenuissimum, 

47, 49

Rhodochorton variabile, 47, 50

Rhodoglossum, 

Rhodoglossum affine, 337

Rhodoglossum diffusum, 335, 

336

Rhodoglossum digitatum, 

336

Rhodoglossum hancockii, 

336

Rhodogorgonales, 11, 76

Rhodomela,

Rhodomela radicans, 239

Rhodomelaceae, 149, 238, 284, 

475, 476, 478

Rhodomelaceae tribus

Bostrychieae, 239

Rhodomelaceae tribus

Brongniartelleae, 286

Rhodomelaceae tribus

­Chondrieae, 240

Rhodomelaceae tribus

­Herposiphonieae, 244, 284

Rhodomelaceae tribus

Laurencieae, 248

Rhodomelaceae tribus

Lophothalieae, 286

Rhodomelaceae tribus Polysiphonieae, 261, 284, 285

Rhodomelaceae tribus Pterosiphonieae, 279, 284, 285

Rhodonematella, 39, 74, 75

Rhodonematella subimmersa, 

39, 75

Rhodonematellaceae, 38, 39

Rhodophyceae, 15

Rhodophycophyta, 11

Rhodophysema, 74

Rhodophysemataceae, 39, 74, 75

Rhodophyta, 1, 11, 12, 13, 475, 

477, 479

Rhodophytina, 13

Rhodoplantae, 13

Rhodospermeae, 11

Rhodymenia, 460, 465, 467

Rhodymenia arborescens, 467

Rhodymenia californica, 467

Rhodymenia dawsonii, 467, 

467, 496

Rhodymenia divaricata, 467,

467, 468, 496

Rhodymenia hancockii, 467, 

468, 468, 469, 496

Rhodymenia huertae, 467, 

469, 475, 478

Rhodymenia rosea, 469

Rhodymenia? tepocensis, 

389, 469

Rhodymeniaceae, 442, 455, 

460, 475, 476, 478

Rhodymeniales, 143, 442, 475, 

476, 478

Rhodymeniophycidae, 34, 142

Rufusia, 12

Rufusiales, 13

Sahlingia, 17, 18, 19, 24, 25

Sahlingia subintegra, 18, 19, 

25, 479

Saitoa, 249, 256

Salishia, 342

Sarcodiotheca, 268, 353, 354, 

358, 363

Sarcodiotheca caribaea, 354

Sarcodiotheca dichotoma,

354, 355, 478, 492

Sarcodiotheca elongata, 358

Sarcodiotheca furcata, 354,

356, 357, 358, 492

Sarcodiotheca gaudichaudii, 

352, 353, 354, 358, 359, 

492

Sarcodiotheca linearis, 354, 

358, 360, 433

Sarcodiotheca taylorii, 354, 

360, 360, 385, 478, 492

Sarcomeniaceae, 149, 214, 236

Sarcophyllis, 

Sarcophyllis californica, 434

Sargassum, 8, 9, 15, 42, 43, 48, 

87, 116, 120, 121, 136, 

138, 139, 146, 153, 159, 

174, 218, 242, 248, 253, 

258, 268, 271, 297, 301, 

481, 484, 485, 486, 487, 

490

Sargassum liebmannii, 139

Sargassum linifolium, 117

Sargassum palmeri, 163

Sargassum sinicola, 290, 485

Sargassum sinicola var. 

camouii, 488

Scageliopsis, 155

Schizoseris, 214, 230, 232, 233

Schizoseris bombayensis, 232, 

233

Schizoseris minima, 233

Schizoseris pygmaea, 232,

232, 233, 487, 488

Schizoseris subdichotoma, 233

Schizymenia, 76, 432, 433, 434

Schizymenia apoda, 429, 432

Schizymenia? coccinea, 364

Schizymenia dubyi, 434

Schizymenia johnstonii, 417, 

434

Schizymenia pacifica, 434,

435, 436, 495

Schizymenia violacea, 417, 

434

Schizymeniaceae, 429, 430, 

432, 433, 478

Schizymenieae, 432

Scinaia, 44, 47, 48, 49, 68, 69

Scinaia articulata, 49, 72, 73

Scinaia complanata, 70

Scinaia confusa, 49, 68, 69, 

70, 481

Scinaia cottonii, 74

Scinaia forcellata, 68

Scinaia furcellata, 68

Scinaia furcellata f. complanata, 70

Scinaia furcellata var. undulata, 69, 70

Scinaia interrupta, 68, 69

Scinaia japonica, 72, 73

Scinaia johnstoniae, 49, 69, 

70, 71, 72, 73, 481

Scinaia latifrons, 47, 69, 73, 

73, 74, 481

Scinaia minima, 72, 73

Scinaia snyderae, 69, 70

Scinaia undulata, 69, 70

Scinaia tokidae, 72, 73

Scinaiaceae, 50, 51, 68

Sebdenia, 419, 440

Sebdenia actinophysa, 419

Sebdenia agardhii, 440

Sebdenia flabellata, 143, 

440, 441, 486, 495

Sebdenia limensis, 409

Sebdenia polydactyla, 440, 

441

Sebdeniaceae, 440

Sebdeniales, 143, 439, 440

Sinotubimorpha, 11, 12

Sinotubimorpha catenata, 

411, 412

Sinotubimorpha porracea, 

411, 412
NUMBER 96 • 555

Smithora, 

Smithora naiadum, 31

Solieriaceae, 304, 319, 352,

353, 363, 473, 475, 476, 

478

Sonderopelta, 366

Sorella, 214, 233

Sorella delicatula, 233

Sorella delicatula var. californica, 233

Sorella divaricata, 233

Sorella pinnata, 233, 234, 

487, 488

Spermothamnion, 

Spermothamnion phycophilum, 298

Spermothamnion saccorhiza, 

298

Spermothamnion snyderae, 

298, 300

Spermothamnion snyderiae 

var. attenuata, 298

Spermothamnion sp., 297

Sphacelaria, 15, 19, 21, 23, 24, 

40, 42

Sphacelaria pennata, 280

Sphaerococcus, 

Sphaerococcus chauvinii, 331

Sphaerococcus coronopifolius, 

123

Sphaerococcus miniatus, 363

Sphaerococcus papillatus, 331

Sphaerococcus pedicellatus, 

206

Sphaerococcus repens, 449

Sphaerococcus spinellus, 324

Sphaerococcus sternbergii, 

415

Sphaerococcus subulatus, 358

Sphaerococcus textorii, 394, 

396

Spongites, 78, 115, 118, 122, 

123, 124, 125, 127

Spongites decipiens, 125,

126, 136, 483

Spongites discoideus, 111

Spongites fruticulosa, 127, 

140

Spongites onkodes, 130

Spongites sonorensis, 130

Spongites yendoi, 125, 126,

127

Sporolithaceae, 77

Sporolithales, 76, 77

Sporolithon, 77

Spyridia, 288, 290

Spyridia filamentosa, 288, 290

Spyridia cf. filamentosa, 288,

289, 290, 490

Spyridia griffithsiana, 290

Spyridiaceae, 149, 288

Squamariaceae, 366

Stictosiphonia, 239

Stylonema, 14, 15, 16

Stylonema alsidii, 15, 16, 479

Stylonema cornu-cervi, 15, 

16, 479

Stylonema elegans, 15

Stylonemataceae, 13, 14

Stylonematales, 13

Stylonematophyceae, 13

Tacanoosca, 12, 192, 270, 353, 

360, 361, 362, 475

Tacanoosca uncinata, 8, 9, 

20, 361, 362, 363, 476, 

492

Taenioma, 214, 235

Taenioma clevelandii, 237

Taenioma dotyi, 235

Taenioma perpusillum, 235,

236, 488

Tayloriella, 238, 282, 284

Tayloriella dictyurus, 284

Taylorophycus, 

Taylorophycus laxa, 459

Tenarea, 

Tenarea ascriptica, 114

Tenarea canescens, 113

Tenarea confinis, 115

Tenarea dispar, 113

Thallophyca, 12

Thoreales, 37

Tiffaniella, 291, 296, 297, 298, 

299

Tiffaniella phycophilum, 298

Tiffaniella saccorhiza, 298,

299, 490

Tiffaniella snyderae, 288, 

298, 299, 300

Tikvahiella, 352

Titanoderma, 78, 102, 112, 113

Titanoderma ascripticium, 114

Titanoderma canescens, 113

Titanoderma capsicum, 102

Titanoderma confine, 115

Titanoderma corallinae, 103

Titanoderma dispar, 113,

114, 482

Titanoderma pustulatum var. 

confine, 113, 115

Titanoderma pustulatum 

var. pustulatum, 102, 112, 

113, 114

Titanophora, 432

Trailliella, 143, 147

Trailliella intricata, 147

Trailliella-phase, 143, 147

Trichoceras, 

Trichoceras pubescens, 184

Tricleocarpa, 39, 47, 52, 60

Tricleocarpa cylindrica, 52, 

60, 61, 481

Tricleocarpa fragilis, 52, 60, 

61, 62

Tricleocarpa oblongata, 62

Tsengia, 426, 429, 430, 434

Tsengia abbottiana, 426,

427, 428, 429, 431, 434, 

476, 494

Tsengiaceae, 143, 405, 426,

430, 473, 476

Turnerella, 

Turnerella pacifica, 434

Tylotus, 

Tylotus cunninghamii, 378

Ulva, 15

Ulva furcellata, 68

Ulva intestinalis, 48

Ulva nematoidea, 174

Ulva purpurea, 30

Valoniopsis, 25

Veleroa, 238, 286, 287, 288

Veleroa subulata, 286, 287, 

288, 490

Verrucaria, 

Verrucaria rubra, 37

Verrucaria tavaresiae, 35

Verrucariales, 35

Weeksia, 364, 365, 366

Weeksia coccinea, 364, 365, 

492

Weeksia fryeana, 364

Weeksia templetonii, 364,

365, 366, 421, 492

Weeksiaceae, 363, 364

Wengania, 12

Wildemania, 30

Wrangeliaceae, 149, 288, 291,

478

Wrangeliaceae tribus Griffithsieae, 291

Wrangeliaceae tribus Spermothamnieae, 296

Wrangeliaceae tribus Spongoclonieae, 300

“Wrangelieae”, 291

Wurdemannia, 304, 326, 353, 

363

Wurdemannia miniata, 304, 

363

Wurdemannia setacea, 363

Wurdemanniaceae, 363

Yuzurua, 249

Zanardinia, 

Zanardinia marginata, 53

Zanardinula, 

Zanardinula abbreviata, 423

Zanardinula abbreviata var.

guaymasensis, 424

Zanardinula acroidalea, 425

Zanardinula cornea, 425

Zanardinula delicatula, 425

Zanardinula filiformis f. 

delicatula, 425

Zanardinula guaymasensis, 

424

Zanardinula kinoensis, 425

Zostera, 24, 48, 267

Zostera marina, 23
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